Lies, Damned Lies, and Miscarriage Statistics

Trying to figure out your chances of miscarrying? Sadly, you are going to have a hard time finding good information. 

Many websites claim to tell you your risk of miscarriage, citing statistics that look like these:

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But problems abound with their numbers.

Problem 1: These sites rarely provide their sources, so you cannot tell whether their information is reliable.

Problem 2: These sites do not breakdown miscarriage risk by other known risk factors, like the mother’s age.

Problem 3: Nearly all these sites derive their statistics from just two small studies, one which tracked 222 women from conception through just the first 6 weeks of pregnancy, and another which tracked 697 pregnancies, but only after a fetal heartbeat had been detected–a key point, because heartbeat detection dramatically lowers the chances of a miscarriage.

The lack of good information frustrated me when I was pregnant, and I bet it frustrates you too. So I have compiled a summary of the best research on risk of miscarriage. Where possible, I break down the risk by…

Edit: I also have a new post on how morning sickness signals a lower risk.

Continue reading Lies, Damned Lies, and Miscarriage Statistics

How Egg Freezing Success Rates Change with Age

A few months back, a friend asked that I write about egg freezing:

“As a single woman in my mid-30s who has always been a strong maybe on kids (with preference for yes with right partner/financial circumstances), I’m now in a place where I feel like I need to start planning for either children and partner or freezing my eggs or SOMETHING before the options run out in the next few years… But most people online seem to be writing personal horror stories with multiple IVF fails.”

Many women face a similar quandary, wondering if they should freezing their eggs before it’s too late. Here’s what you need to know about egg freezing to make an informed decision.

Continue reading How Egg Freezing Success Rates Change with Age

Vitamin D in Breastmilk and My Daughter’s Diagnosis with Type 1 Diabetes

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Sydney, catching bubbles at her birthday party this month.

A few weeks ago, I was all set to write about the vitamin D needs of pregnant and nursing women. Increased sunscreen use and less time spent outdoors means that few women can meet their vitamin D needs through sunlight exposure alone. As a result, many pregnant women are insufficient in the vitamin.

The medical community is clearly concerned about women’s low levels of vitamin D: The American Pregnancy Association recently raised their recommended vitamin D intake for pregnant and nursing women from 400 IU to 4000 IU, a tenfold increase. The change was precipitated by a recent randomized control trial, in which supplementation with 4,000 IUs a day was shown to be safe and highly effective at reducing vitamin D deficiency among pregnant women.

I only wish these changes had come sooner.

I say this because last weekend, my daughter Sydney, who turned two this month, was diagnosed with Type 1 Diabetes–a disease that may be staved off, in part, by high levels of vitamin D during infancy.

Continue reading Vitamin D in Breastmilk and My Daughter’s Diagnosis with Type 1 Diabetes

The NEJM Peanut Study: Is It Better to Introduce Allergenic Foods Early?

By now, you’ve probably heard about the recent study, which showed that early consumption of peanuts lowers the risk of peanut allergy by as much as 86%.

 The study, led by Gideon Lack of King’s College, London, and published in the New England Journal of Medicine in February, is the first randomized clinical trial conducted on preventing peanut allergy in children. Widely hailed as a game changer, the study’s findings are already affecting the advice given to parents.

Just last week my friend’s pediatrician counseled her to “stir a little peanut butter” into her 6-month-old’s rice cereal. She barely managed to avoid gaping at him in astonishment. Just two years earlier, with her first child, he had told her to avoid introducing peanuts for the first year.

After decades of conflicting advice and vague admonitions, parents may wonder whether such a dramatic change is actually warranted. Is the evidence any better now than it was ten years ago? And if the guidelines were so mistaken before, why have confidence in them now?

And, perhaps the biggest outstanding question of all: what, if anything, does this study mean for when to introduce other highly allergenic foods, like fish, tree nuts, or eggs?

Continue reading The NEJM Peanut Study: Is It Better to Introduce Allergenic Foods Early?

The Fertility Cliff at Age 35 is a Myth

Several years ago, before I was married or had even begun dating my husband-to-be, I was chatting with a reproductive endocrinologist about when I needed to worry about my fertility going into decline. I was about to turn 30. Should I be worried? And how many quality reproductive years did I have left?

She told me most women were fine at 30 or 35. At her clinic, she said, she rarely saw women with problems related to “advanced ovarian age” before they turned 37 or 38.

I was surprised, to say the least. Like so many women, I had heard ad nauseam about “getting pregnant after 35.”

Despite all the chatter, I was not actually clear on why 35 was an important cutoff. Was it because getting pregnant was more difficult after 35? Or staying pregnant became challenging after 35? Or was that the age when the risk of chromosomal abnormalities like Down’s syndrome rose dramatically?

It turns out that none of these reasons are correct. Because in fact there is no reason; age 35 is not actually a cliff. It is not even a sharp bend in the curve, a point at which birth rates go into a steep decline. Those sharp bends come later, after 37, and again after 40.

So why has age 35 been etched into our consciousness? Continue reading The Fertility Cliff at Age 35 is a Myth

Fertility in Your 30s and 40s: 7 Things You Need to Know

One of my former colleagues became pregnant her first shot out of the barn, the first month off the pill. Her story would hardly be noteworthy, except that she was 41 at the time.

She wanted to tell other women about her experience, she confided to me. She saw it as a sign that women can have children after age 40.

I simply nodded in response, while I privately wondered if she had not just been very lucky.

But–and this is key–how lucky?

Having a baby in your 30s and early 40s–and earlier, for that matter–is always a chance event. There will be outliers. Some women will give birth naturally at 44. Some women will suffer from early menopause at age 30. But outliers tells us little about the norm.

Anyone who wants to play the conception game, especially if they are postponing childbearing, needs to put anecdotes aside and try to grasp the actual odds. Here’s what every woman needs to know:

Continue reading Fertility in Your 30s and 40s: 7 Things You Need to Know

Does Giving Birth “Reset” a Woman’s Fertility?

Do couples have an easier time getting pregnant after they have already had a child?

I’ll confess, my interest in this topic is personal. We were one of these couples. We took over a year to conceive my son, but our second was a surprise.

Back when my first was born, as we were getting ready to head home after three long days in the hospital, with round-the-clock wake ups, I made the mistake of telling our delivery nurse that we were not planning to use birth control.

She immediately launched into a lecture that we needed birth control. “Giving birth can reset your fertility,”  she stated matter-of-factly. And then added sternly that we needed to start using birth control as soon as we resumed having sex.

Although she briefly made me feel like an errant teenager, I did not take her advice very seriously.

Various reputable sources of medical information, such as WebMd, state that the prior births do not “reset” a woman’s fertility,asserting that the notion is a myth.

Two recent studies, however, suggest there might be something to this idea after all.

Kenneth Rothman of Boston University, led a prospective study, which followed 2820 Danish couples who were trying to conceive for up to 12 cycles.

Rothman then calculated how the woman’s age affected a couple’s fecundability ratio–a statistical estimate of a couple’s ability to conceive each menstrual cycle.

Couples in which the woman had given birth before–about half of the couples in their early 30s and two-thirds of those in their mid to late 30s–had much higher fecundability throughout their 30s:

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Continue reading Does Giving Birth “Reset” a Woman’s Fertility?

Giving Birth Takes Twice As Long It As It Did 50 Years Ago

My first labor was long. Really long. It lasted from Friday night to Sunday evening. Pain I had anticipated, prepared for, given myself multiple pep talks for, but the duration… It undid me.

As I recently watched a good friend go through a similar labor, some old nagging questions resurfaced: How uncommon is it for women to labor for days? What is a “normal” length of labor, if such a thing exists?

Oddly enough, the medical answers to these questions have just changed dramatically. This is because of a recently completed landmark study of nearly 100,000 labors. The study, which used medical record data collected between 2002 and 2008 from hospitalsm across the U.S., showed unequivocally that we labor much more slowly than we used to. Much, much more slowly.

In fact, our labors have slowed down so much that in 2014 the American College of Obstetricians and Gynecologists (ACOG) revised its definitions of normal and overly slow laborUntil then, the definitions were based on data from the 1950s and 1960s. These data were used to define a “normal” labor duration, how long it takes most women in active labor to reach a full 10 cm of dilation and then to push the baby out. By the same token, these data were used to defined abnormal labor: labors that lasted longer than 19 out of 20 of these labors (the 95th percentile for duration) were considered overly slow or stalled.

Continue reading Giving Birth Takes Twice As Long It As It Did 50 Years Ago

The Fetal “Gender Nub”: How To Learn Your Baby’s Gender at the First Trimester Screening

Kudos to people who can wait until the birth to find out if they are having a boy or girl. The feminist in me feels guilty about this, but I never wanted to wait that long. Pretty much the second I learned I was pregnant, I started trying to figure out if it was a boy or or girl.

The good news for people like me: ultrasounds can now detect a baby’s gender as early as 12-13 weeks gestation.

Genetic testing through CVS remains the most accurate way to determine fetal sex in the first trimester. But since this test carries a slight risk of miscarriage, many of us choose not to have it performed. (New blood-based tests that rely on cell free DNA can detect your baby’s gender as early as 9 weeks, without increasing the risk of miscarriage, but these are only about 95% accurate in the first trimester).

Until recently, forging genetic testing meant we had to wait until the second trimester screening to learn our baby genders, sometime around 18 to 20 weeks gestation. By that time, the penis, testes, and labial folds are clearly visible on an ultrasound.

The latest research, however, suggests we can learn the gender months earlier, during the ultrasound for the first trimester screen, which is performed sometime between 11 weeks 0 days to 13 weeks 6 days of gestation. The key is scheduling your scan towards the end that window.

Male and female fetuses look pretty similar throughout most of the first trimester. The genitalia are just starting to develop from their root, the “genital tubercle,” which slowly develops into either a penis or clitoris. This genital tubercle is same size in boys and girls until around 14 weeks gestation, when the penis begins to elongate.

A sonographer therefore has to rely on more subtle clues to determine gender in the first trimester. The angle of the genital tubercle is one important clue. By 12-13 weeks gestation, the angle of the penis begins to point up, towards the baby’s head, while the clitoris remains flat or points slightly down.

The ultrasound images below illustrate this. A male fetus is shown on the left, a female fetus on the right. The angle of the genital tubercle is noted with faint white lines.

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From Efrat et al. 1999

In small study of 172 pregnancies, sonographers  were able to accurately detect fetal gender using this angle from about 12 weeks on. Before then, sonographers correctly identified only 70% of fetuses. They were most prone to misclassify the boys: roughly half of the male fetuses were misclassified as girls. So at 11 weeks, when the sonographers guessed that a fetus was a boy, they were usually correct. But when they guessed it was a girl, they were often wrong.

But by 12 weeks this method’s accuracy shot up to 98%. By 13 weeks, there were no more misidentifications; 100% of their classifications were correct. In a follow-up study of 656 pregnancies, sonographers were again perfectly accurate by 13 weeks.

At this point in pregnancy, using the angle of the genital tubercle is more accurate than trying to detect the labia or testes, the method commonly used to determine gender in the second trimester. Classification by the latter method was only about 75% accurate until 14 weeks.

(Incidentally, several websites, like this post at CafeMom and this one at About Health, claim that fetal gender can be detected with nearly 100% accuracy at the 6-8 week ultrasound using “Ramzi’s Method”. I tracked these claims down. All of them appear to derive a paper written by Dr. Saad Ramzi Ismail, which was posted to obgyn.net last year (and has since been removed). In it, Dr Ismail claims that the placenta is almost always on the left side for girls and on the right side for boys. While her paper is formatted and reads like a legitimate scientific article, it was never published in an actual scientific journal. Moreover, it seems extremely unlikely that, if we could determine gender by something as simple as the location of the placenta, we would already know this and use this method all the time. So, as far as I can tell, “Ramzi’s method” is pure junk science.)

The Bottom Line

If you want to learn your baby’s gender, schedule your first trimester scan for 13 weeks gestation. The methods used to detect gender at this fetal age are pretty new, so some sonographers may be hesitant to give your their best guess. But don’t let this deter you. Ask! They are very likely to get it right.

Additional Reading

Like this post? You may also like my take on fetal sex tests based on cell free DNA. With a simple blood draw, these tests can determine fetal sex as early as 9 weeks.

References

Efrat Z. Akinfenwa O.O, and Nicolaides K. H. (1999). First-trimester determination of fetal gender by     ultrasound. Ultrasound Obstet Gynecol 13:305–307.

Efrat Z., Perri T., Ramati E., Tugendreich D., and Meizner I. (2006). Fetal gender assignment by first-trimester ultrasound. Ultrasound Obstet Gynecol.27(6):619-21.

Emerson D.S., Felker R.E., and Brown DL. (1989). The sagittal sign. An early second trimester sonographic indicator of fetal gender. J Ultrasound Med. Jun;8(6):293-7.

Introducing Solids: Is It Best to Wait Until 6 Months?

In 2005, the American Academy of Pediatrics (AAP) changed their recommendations from gradually introducing solids between 4 and 6 months of age to exclusively breastfeeding for “about the first 6 months of life. For the first 6 months “your baby”, they assert, “needs no additional foods (except Vitamin D) or fluids unless medically indicated.”

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My daughter at 9 months, eating peas and Cheerios

You might think that these recommendations were updated because of a new evidence showing substantial benefits for the baby of delaying the introduction of solids.

But, nope, this is not the case. Instead, these changes were motivated by studies showing an absence of harm to the baby and some minor potential benefits for the mother.

The World Health Organization was the first major medical organizations to recommend exclusive breastfeeding for 6 months, for reasons they outline in a 2002 research review (updated in 2007):

  1. No evidence exclusive breastfeeding for 6 months results in poor growth
  2. No apparent increase in the risk of allergies*
  3. A longer period of lactation-induced infertility, about an extra month on average
  4. Greater postpartum weight loss between 4-6 months, about a pound on average
  5. Lower risk of illness for the first six months, and possibly throughout the first year

* (Since this review was published, new evidence suggests delaying solids until 6 months may increase the risk of food allergies. More on this complex topic below.)

When weighing the pros and cons of exclusive breastfeeding for 6 months, the social and environmental context matters. The WHO crafted its guidelines to maximize health outcomes in both developing and developed nations. But benefits that have a large public health impact in the developing world, where access to basic medical care, birth control, clean water, and nutritious food is limited and inconsistent, can have little or no impact in the developed world.

Benefits of Exclusive Breastfeeding for Six Months

For mothers living in the developed world, the benefits of exclusive breastfeeding for 6 months are small, arguably negligible.

We have been blessed with access to birth control, so lactation-induced infertility is not a critical means of pregnancy prevention and birth spacing.

And, when it comes to weight loss, although almost every mother I know would gladly shed an extra pound or 2 of baby weight, the benefit is really small, just an extra a pound on average. Surely there are other activities that do not require 8-hours a day, round-the-clock efforts that would be just as effective forms of weight loss.

Certainly neither of these two benefits warrant the stress placed on introducing solids “at the right time.”

Of the reasons given by the WHO, the only truly persuasive one is a reduced risk of illness for the baby during its first 6 to 12 months of life. Here again, though, there are important differences between the developing and the developed world.

In the developing world, exclusive breastfeeding for 6 months is literally life saving. Within the 42 nations with the highest child mortality rates, widespread adoption of exclusive breastfeeding for 6 months would prevent an estimated 13% of the deaths of children under the age of 5. This is a larger percentage than would be saved with improved access to antimalarial medication or antibiotics.

Within the developed world, the picture is more nuanced. Here, completely weaning from breast milk before 6 months, or introducing solids before 4 months, or introducing formula before 6 months substantially increases the risk ear infections, diarrhea, pneumonia, and bronchitis.

But gradually introducing solids between 4 to 6 months while continuing to breastfeed does not. Studies that compare the outcomes of infants who were exclusively breastfed until 6 months (EBF or exclusively breastfed) with those who were exclusively breastfed for at least 4 months and then partially breastfed thereafter (MBF or mostly breastfed) find that 6 months of exclusive breastfeeding neither harms nor benefits growth and development.

The only apparent benefit of delaying until 6 months was a 25-50% lower risk of diarrhea in the first year of life. The effects on ear infections, pneumonia, and bronchitis were unclear: A couple of observational studies found a lower risk, but the majority of studies, including the only two randomized controlled trials, found no effect. And longitudinal study conducted in Belarus found no differences in weight, height, BMI, asthma, allergies, or other illnesses by age 6.

“Exclusive breastfeeding for six months does not seem to confer any long-term (at least to early school age) protection against obesity or allergic disease, nor any benefits in cognitive ability or behaviour, compared with exclusive breastfeeding for three to four months with continued partial breastfeeding to six months.”  – Kramer & Kakuma, 2012

Costs of Exclusive Breastfeeding

Lower Iron Status. EBF infants tend to have lower iron levels than mixed fed or formula-fed infants. Two randomized controlled trials, one conducted in Honduras and the other in Iceland, found significantly higher iron levels among MBF than EBF infants. Reassuringly, at 6 months of age, iron levels in both groups remained within the normal range, and the EBF infants were not more likely to be iron deficient or to develop anemia.

Still, iron needs rise sharply in the second half of the first year when newborn iron stores have been depleted, and lower iron status in the first six months could place EBF babies at higher risk of iron deficiency as they age. This is why the CDC considers “breastfed babies who after age 6 months are not being given plain, iron-fortified cereals or another good source of iron from other foods” to be at high risk for iron deficiency and anemia.

Increased Risk of Food Allergies. On this point, the advice given to parents has seesawed from it is best to delay solid foods, especially highly allergenic ones, to it is best to introduce these foods early, between 4 to 6 months. This is because the evidence behind the advice is of poor quality and inconsistent. A handful of observational studies find that early introduction increases the risk of allergies. A comparable number find that late introduction increases the risk. And not all of the studies find when solids are introduced matters at all.

Some researchers to speculate that there is something of a sweet spot in infancy, between 4-6 months of age, when introducing solids lowers the risk of allergies. This protective effect may be strongest for peanuts and cooked whole eggs. But until proper clinical trials have been done, it seems wise not to make too much of these findings. (UPDATE: A randomized controlled trial has now shown that introducing peanuts before 1 year of age lowers the risk of a peanut allergy substantially. More on this study here.)

The AAP no longer recommends waiting to introduce solids until 6 months or later to reduce the risk of allergies, and instead advises waiting until at least 4 months. And of course, this statement on solids and food allergies conflicts with guidance the AAP gives elsewhere to exclusively breastfeed for 6 months.

Conclusions

Like so many parenting decisions, the actual evidence suggests that we can all relax a bit. For those of us lucky enough to live in the developed world, introducing a small amount of solids between 4 to 6 months is unlikely to harm our babies, and equally unlikely to benefit them.

That said, when giving your baby solids before 6 months, it makes sense to provide small amounts. The immune benefits of breast milk are dose-dependent: the more milk the baby takes in, the greater the protection from illness. This is why solids during the first year should not be used to replace but to supplement breastfeeding. And when introducing solids, especially to exclusively breastfed babies, it makes sense to emphasize iron rich foods like broccoli, meat, eggs, fish, and fortified cereals.

Here is most sensible statement I found on the 6-month rule, from a review article in The BMJ, the flagship journal of the British Medical Association:

“From a biological perspective, the point when breast milk ceases to be an adequate sole source of nutrition would not be expected to be fixed, but to vary according to the infant’s size, activity, growth rate, and sex, and the quality and volume of the breast milk supply.”  – Fewtrell, Booth, & Lucas, 2010

When did you first introduce solids? Did the risk of allergies or infections play a role in your decision?

Inducing Labor Past 39 Weeks Does Not Increase Your Chances of Having a C-Section

Pregnant women often fear that having their labor induced will lead to a c-section. In her bestselling book, Expecting Better, Emily Oster cites fear of a c-section as the primary reason she opted not to have her labor induced. Other reputable sources like the Mayo Clinic Online and March of Dimes claim that inductions increase the odds of a c-section.

But, according to the latest scientific research, these fears are unfounded. Past 39 weeks, labor inductions do not appear to raise the risk of having a c-section. Instead, being induced lowers your chances of a c-section by about 20%.

How did we get this so wrong? Until about 5 years ago, almost all the evidence on inductions and c-sections came from observational studies, which were all subtly biased, because they compared women who went into labor on their own with women who were induced.

What was wrong with this comparison?

Observational studies typically control for gestational age. This means that, in effect, they match women by the week they delivered, because the risks associated with giving birth climb as pregnancies continue past 39 weeks. Women who went into labor spontaneously at 39 weeks were compared to women who were induced at 39 weeks, and so on.

And, when matched by delivery week, women who go into labor spontaneously are less likely to have c-sections.

So what’s the problem? Pregnancies that go into labor spontaneously by a certain week are different from those that don’t.

Think about it this way: What is choice women actually face past 39 weeks? Women cannot will themselves into labor, or there would be a lot fewer pregnancies going past 40 weeks. Instead, pregnant women can only choose either to be induced or to wait it out.

So the proper study design compares these two options: being induced versus waiting it out. This is the approach taken by recent randomized controlled trials on inductions.

In these trials, pregnant women are randomly assigned to be induced past a certain point in pregnancy, for example, at 41 weeks, or to wait it out. Women assigned to wait may go into labor on their own or be induced at a later date. Using this approach, studies find, almost without exception, that relative to waiting and delivering at a later point in pregnancy, inducing labor leads to a lower chance of a c-section.

A 2009 meta-analysis (combined analysis of multiple studies) was the first to convincingly reveal the problem.

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The analysis compared the results of observational studies and randomized controlled trials (RCTs). The observational studies found a roughly 20% increase in the risk of c-section following inductions; the better-designed RCTs found a roughly 20% reduction in the risk.

Continue reading Inducing Labor Past 39 Weeks Does Not Increase Your Chances of Having a C-Section

Trying to Bring On Labor? Forget Sex and Spicy Foods. Only Nipple Stimulation Works.

In February, I hit my due date. 40 weeks! I thought. Let’s get this show on the road. Then… nothing. 40 weeks 1 day came and went. 40 weeks 2 days. 40 weeks 3 days…

My belly felt enormous, like an overripe melon. And in a not-so-funny coincidence, this was exactly how my favorite pregnancy app described my baby’s current size.

We needed to get this baby on schedule.

So my husband and I went out to eat spicy food. Thai, Indian, Mexican. The hotter the better.

And in return for a scorched tongue and numbed taste buds, all I ended up with was indigestion.

Then I tried walking. Lots of walking. I dragged my heavy, swollen body on long hike after long hike, completing them at a pace best described as a fast waddle.

In the end, I went almost a week late—barely avoiding a medical induction—and only after having my membranes swept twice.

At my 39 weeks appointment for my second pregnancy, my OB predicted that I would again go a week late. “That’s just how you bake them,” she chirped at me, while giving a matter of fact state-of-the-cervix rundown: I was not dilated or effaced, and my cervix was still posterior. The only thing I was, it seemed, was deeply disappointed.

But this time around I had done research on natural methods of inducing labor. That weekend, I pulled my breastpump out of the closet, sterilized my nipple shields, plopped them on, and sat down to pump for a couple of hours while watching a movie. Coincidentally or not—I’ll never really know—I went into labor two days later and delivered right on my due date.

In retrospect, though, by inducing labor in this way, I may have unwittingly taken a bigger risk with my baby’s health than I am completely comfortable with.

In my efforts to bring on labor, I am hardly alone. According to a recent survey, 50% of pregnant women report trying at least one natural method to bring on labor. Walking is the most popular approach (43%), followed by intercourse (29%), eating spicy foods (10.5%), and nipple stimulation (7.5%). The grand irony here is that nipple stimulation, the least common approach, is the only one with solid scientific support.

Using nipple stimulation to bring on labor has a long history. Midwives in the 18th and 19th centuries used the practice to speed up stalled laborsNipple stimulation brings on labor by releasing oxytocin, the hormone that causes contractions. Hospitals use a synthetic version of the same hormone, pitocin, to induce or augment a stalled labor.

A 2005 meta-analysis of six randomized control trials (the gold standard for medical studies) found that nipple stimulation increases the likelihood of labor. A total of 719 pregnant women at term were randomly assigned to stimulate their nipples for several hours or not. 37.8% went into labor within the 3 days following nipple stimulation, compared to 6.4% of the controls.

This difference, large in relative terms, was statistically significant. Still, two-thirds of women failed to go into labor even after nipple stimulation—underscoring that the method is no guarantee of labor.

(Note to the do-it-yourselfers or those fearful of accidentally inducing labor: Nipple stimulation in these studies did not consist of a few random suckles, squeezes, or tugs. It was a serious, concerted effort. Women were instructed to gently stimulate one nipple for 10–15 minutes before switching to the other side, and to continue alternating between breasts for an hour, 3 times a day.)

Using nipple stimulation for inducing labor would probably be a more widely known and recommended practice were there not concerns about its safety. One of the studies in the 2005 meta-analysis, conducted with high-risk women delivering at a hospital in India, was stopped early because of 4 fetal deaths: 3 in the nipple stimulation group, and 1 in the oxytocin induction group. (None of the other 5 studies reported any deaths.) Because of this, the meta-analysis concludes:

“Until safety issues have been fully evaluated it [nipple stimulation] should not be considered for use in a high-risk population”

It’s hard to know what to make of these safety concerns. The women in the Indian study were considered high risk because they had intrauterine growth retardation, high blood pressure, or were post-term. But the researchers failed to report which of these risk factors was associated with fetal death, or to provide any additional details about these deaths, other than to say one of fetuses lost did not appear to have any congenital abnormalities.

That nipple stimulation contributed to these deaths is certainly plausible. Nipple stimulation can result in uterine hyperstimulation—contractions that are too frequent or prolonged, and which can lead to fetal distress.* This is why women are told to alternate between breasts instead of stimulating both nipples simultaneously and to pause during contractions.

German study found uterine hyperstimulation occurred in 10% of women during nipple stimulation, and in 1% this was accompanied by reversible abnormalities in fetal heart rate patterns. Based on this, the authors caution against using nipple stimulation without medical supervision:

Due to the conflicting reports in the literature and because of the potential hazards involved, the use of nipple stimulation for the induction of uterine contractions can be advocated only in a controlled clinical setting. Its application without medical supervision, as propagated in the lay press, is definitely contraindicated.

In sum: nipple stimulation does increase the likelihood of going into labor. But because it can cause contractions that are too long or too intense, it is not recommended for women with high-risk pregnancies.

Below is a quick rundown on the evidence (or really, lack thereof) for other natural induction methods:

Walking. Walking is the most recommended and most commonly attempted method of inducing labor. It is true that in late pregnancy, walking seems to increase the frequency and strength of Braxton Hicks contractions. There is no evidence, though, that walking speeds the onset of labor.

Eating spicy foods. There is no evidence that spicy foods cause labor.

Acupuncture. review article of 3 randomized control trials, consisting of 212 women, found that acupuncture reduced the number of women who needed to a medical induction (33% versus 54%), but failed to find a difference in when the women went into labor. Because of the inconsistent results and methods (the type of acupuncture varied between studies), the reviewers felt no conclusions could be drawn without additional research. Since then, other randomized control trials have found no benefit of acupuncture for bringing on labor (see herehere, and here).

Having sex. As one researcher put it, intercourse would be a “safe, effective, and perhaps even fun” [italics mine] way to induce labor. Fun aside, it’s biologically plausible that sex would bring on labor. Semen contains prostaglandins, which are known to ripen the cervix. Orgasms promote the release of oxytocin and can therefore stimulate uterine contractions during late pregnancy. Foreplay involving nipple stimulation could also release oxytocin. A small observational study found that women who reported having sex after 39 weeks were much less likely to go post-term or need to be induced.

Sounds pretty good, right? Alas, the most recent, best-designed, and largest study to date, a randomized clinical trial conducted in Southeast Asia, failed to replicate these findings. Two hundred ten women were recruited from a prenatal clinic, where they had been scheduled for inductions. They were randomly assigned to be counselled by a physician to have sex or to receive standard counselling. The women kept daily diaries tracking when they had sex and whether they experienced an orgasm. Although women who were told to have sex to bring on labor were more likely to have sex before delivery (60% versus 40%), they did not differ in cervical ripeness or in their likelihood to go into labor on their own.

It’s possible that sex does bring on labor, but the Southeast Asian study was too small and therefore underpowered. A sample of 210 women is not large. Compounding this problem, a fair number of the controls still had sex, albeit at a lower rate than cases, watering down the comparison between the two groups.

Knowing this, in a separate analysis of the same data, the researchers compared all the women who reported having sex with the women who did not, regardless of whether they had been cases or controls. They still found no effect of intercourse. If anything, women who had sex during the study period went into labor later than women who refrained. An earlier but smaller clinical trial similarly found no benefit of sex.

In sum: sex late in pregnancy—after 39 weeks—does not appear to bring on labor. But it perhaps just might be fun.

Did you try any natural methods to induce labor? And do you think they worked?

Footnote

* The evidence on nipple stimulation and uterine hyperstimulation comes mainly from a series of studies conducted in the 1980s. These studies examined whether nipple stimulation was a viable alternative to pitocin for use in contraction stress tests. Constraction stress tests monitor fetal heart rate during contractions to ensure the fetus can safely withstand labor. The studies variously found no instances of hyperstimulation, hyperstimulation in 10% of women, and hyperstimulation in 12% of women. A final study, which also reported on fetal distress, found hyperstimulation with fetal heart rate changes in 2.9% of women using nipple stimulation, compared to 1% of women using pitocin.

Let’s Face It: Formula-Fed Babies Sleep Better

Breastfeeding is a major battleground of the modern mommy wars. In her widely discussed piece in The Atlantic, Hanna Rosin called breastfeeding the “new sucking sound”–replacing vacuuming as the task that shackles women to the house, promotes the unequal distribution of childcare and household duties, and prevents women from reaching the upper echelons of professional success. The benefits of breastfeeding have been oversold, she claims, and–just as significantly–the costs to women’s sleep, time, and career progress have been downplayed.

On the other side of the debate, the American Academy of Pediatrics states that the benefits for the infant in terms of reduced risk of infection, adult obesity, allergies, and asthma are so great that breastfeeding must be viewed as an “investment in your child’s future” rather than a “lifestyle choice.” Some lactation consultants fall into this camp too, needing to be reminded to suppress their impulse to sigh when yet another mother complains of exhaustion and lack of sleep, for fear they alienate her–and thus fail to convince her to keep breastfeeding.

On both sides, well-intentioned but overzealous advocates twist the evidence on breastfeeding, cherry-picking among studies to support their preexisting views.

This is especially true when it comes to one of breastfeeding’s major downsides: Disrupted sleep.

Consider the post, 5 Cool Things No One Ever Told You About Nighttime Breastfeeding, which claims that the number 1 coolest thing about nighttime breastfeeding is “breastfeeding moms actually get MORE sleep than their formula-feeding counterparts,” and concludes with the rhetorical question: “Did you ever think, when you hear your baby rouse at 2:00am, that they are actually giving you the gift of MORE sleep…?”

To which I would like to respond: No, never, not only because it does not square with my own experience, but also because the research on this topic is clear: breastfeeding moms, on average, get less sleep, not more.

Almost without exception, studies on formula feeding, breastfeeding, and sleep find that breastfed babies wake up more often than formula fed ones at night, and breastfeeding mothers therefore get LESS uninterrupted nighttime sleep.

Nighttime Wakings in Formula-Fed Versus Breastfed Babies

Continue reading Let’s Face It: Formula-Fed Babies Sleep Better

It’s (Probably) Safe to Sleep on Your Back While Pregnant

My third trimester in my second pregnancy was rough. The days were fine, but the nights were awful. I could not fall asleep. I was too uncomfortable. And as a second time mom, I was desperate. Months of sleep deprivation were my certain future. Pregnancy was supposed to be an opportunity to stock up on sleep before the newborn period.

The only remotely comfortable position was lying on my back, propped up with a couple of pillows. But several pregnancy websites and and my OBs had warned me against sleeping on my back during pregnancy.

More than anything, I wanted to disregard this advice. But I needed to know how big a risk, if any, I would be taking by sleeping on my back.

My OBs were not helpful in this regard. Within the same clinic, one OB told me to avoid lying on my back from 4 months on, another told me to avoid this position from 7 months on, and a third said not to worry until the last month of pregnancy. When asked, none of them could tell me the magnitude of the risk.

Eventually, I dug into the research myself. Once I did, I understood why the advice is confusing to mothers: the underlying research is a mess.

The rationale for this prohibition is simple enough: lying on one’s back can cause supine hypotensive syndrome, sometimes known as aortocaval compression syndrome.

A pregnant woman woman’s belly can compress the inferior vena cava, a large vein running under the right side of her uterus; and compression of the inferior vena cava can cause a drop in blood pressure. In rare cases, the drop in blood pressure is severe enough to reduce heart output, lower oxygen going to the brain, and cause fainting.

Although the drop in blood pressure is unlikely to harm the mother, the concern is that if a pregnant woman’s oxygen levels drop, her baby’s might too. Under normal circumstances, though, women typically become uncomfortable and change their position before their blood pressure takes a serious dip.

lateral versus supine

Supine hypotensive syndrome has been reported as early as the second trimester, but it is mainly a problem of late pregnancy, after 36 weeks or so.

Despite how scary this sounds (“I might be depriving my baby of oxygen without knowing it”), according to a recent research review, back sleeping is safe for the vast majority of pregnant women. The reviewers build a compelling case: First, only very small percentage of pregnant women experience low blood pressure when lying on their back. Even among those women, the changes in their blood pressure do not appear to affect the fetus. Studies have found no effects on fetal blood flow or on fetal well-being during non-stress tests.

Second, the symptoms of low blood pressure (dizziness, nausea, a rapid heartbeat) are easily recognizable. Women can figure out for themselves if lying on their back makes them uncomfortable, and avoid the practice if it does. In the reviewers words:

Advising women to sleep or lie exclusively on the left side is not practical and is irrelevant to the vast majority of patients. Instead, women should be told that a small minority of pregnant women feel faint when lying flat. Women can easily determine whether lying flat has this effect on them, and most will adopt a comfortable position that is likely to be a left supine position or variant thereof.

Third, previous research did not examine back sleeping. The research only addressed positioning women during surgery, when they are completely immobilized and unable to change their position.

This review was written in 2007. Its conclusions are clear and reassuring. Unfortunately, since its publication, two more recent studies muddy these waters a bit.

The first study was conducted at a maternity ward in Ghana. Two hundred twenty women who had recently given birth reported their sleep practices during pregnancy. Compared to women who slept in another position, the 21 women who reported either sleeping on their backs or “backs and sides”, had higher rates of NICU admissions (36.8% vs 15.2%) and stillbirths (15.8% vs 3.0%), and were more likely to have given birth to an underweight baby (36.8% vs 10.7%). Even when the researchers controlled for the mother’s age, number of children, gestational age, and pre-eclampsia, these differences remained statistically significant.

The second study was conducted in New Zealand. Researchers interviewed 155 women who experienced unexplained late stillbirths (after 28 weeks) about their sleep position both before pregnancy and in the last month, the last week, and the last night before their pregnancy ended. Their responses were compared to 301 control women, who were a similar number of weeks along but with ongoing pregnancies.

The researchers carefully controlled for several known risk factors for stillbirth: obesity, smoking, low socioeconomic status, maternal age, and number of prior children. Even so, sleeping on one’s back the night before corresponded to a higher risk of a late stillbirth compared to sleeping on one’s left side.

In fact, sleeping on one’s right side or in any other position than on the left side correlated with a higher risk of stillbirth.

Considered together, these two studies seem reason for caution, but not fear. They have a number of problems. Both were quite small, and both relied on women’s ability to recall what positions they slept in. And for the Ghana study, it’s unclear how the findings translate to women in a high income country.

Even assuming these findings hold up, the absolute risk appears to be very, very low. In the New Zealand Study, during its 3-year study period, the rate of late stillbirth was 3.09/1000. The researchers estimate that left side sleeping would lower the risk to 1.93/1000, whereas right side or back sleeping would raise it to 3.93/1000.

To put this risk further in perspective, the New Zealand study also found that going to the bathroom an average of once a night or less (as opposed to two or more times) was associated with an increased risk of a stillbirth. This magnitude of the increase was comparable to back sleeping. Yet, based on these data, no one has proposed that pregnant women should wake up more often to go to the bathroom.

So, what are we to make of these data? In my personal opinion, the research is not strong enough to support blanket warnings against back sleeping. Yes, there is a plausible mechanism for back sleeping causing problems. But the bulk of the evidence suggests that compression of the vena cava very rarely causes problems.

Depending on her risk tolerance and ability to sleep, one woman might look at these data and feel fine sleeping on her back. Another might choose to sleep exclusively on her left side. Both seem like reasonable decisions.

For me, sleeping with a pregnancy pillow, resting mostly but not completely on my back was the right choice. In part, this was because I wanted to be conservative: A tilt of 10 degrees (such as from propping with a couple of pillows) has been shown to reduce the risk of low blood pressure. This position felt pretty safe. But mostly, it felt comfortable.

Did you avoid lying on or sleeping on your back during pregnancy?

Weight Gain in the Second Trimester: A Sudden Bump Up Is Common — And No Reason to Panic

24 weeks into my first pregnancy, I was feeling smug. I had been eating right, continuing to exercise, and the last dregs of first trimester nausea and fatigue had faded. I was feeling good.

That is, until my OB took me down a few notches at my 6 month appointment.

She told me I had gained “too much weight”. She passed the chart. It was all there in black and white.

Although I had been on target to gain the “correct” amount of weight by the end of my pregnancy, I had gained a whopping 8 lbs in a month. I was now on a trajectory to gain over the upper limit of 35 pounds. She began what was clearly her set lecture. “Eat less bread. Eat only half of the sandwich…”

But as she spoke, my mind began to wander. I was pretty taken aback. I silently reviewed my recent eating habits. No, I did not think they had changed. Certainly not enough to cause a gain of 8 lbs in a month. And yes, I had been exercising my normal amount. If anything, I had become more active in my second trimester. My energy levels had gone up in the last couple of months, not down.

Convinced that I had done nothing dramatically different in the last month, I started to wonder whether we could accurately or reasonably expect a steady rate of weight gain. Maybe it’s normal to gain a lot of weight in the middle of pregnancy, and less towards the end. Maybe pregnancy weight gain looks more like a curve than a line. Continue reading Weight Gain in the Second Trimester: A Sudden Bump Up Is Common — And No Reason to Panic

Evidence-based info for the thinking parent

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