Evidence-based info for the thinking parent
When you finally decide you want a baby, you pretty much want one now. But babymaking takes time. Sometimes way too much time.
Fortunately, you improve your chances of conceiving quickly with a few simple practices.
Today I want to zero in on the most essential: Timing intercourse correctly.
Continue reading “Trying to conceive? Here’s How To Time Intercourse”
That first glimpse of two pink lines–can it be?–and your heart start to pound with excitement. You’re pregnant!
But after a few moments of celebration, you descend back to earth. Okay, you’re pregnant, but for how long? Will this pregnancy stick?
You have entered a new, more hopeful limbo than the much bemoaned two-week wait. But it’s still no picnic.
We all know that miscarriage is very common, especially early in pregnancy. And for most women, good info about viability does not come until the first ultrasound, usually performed at 8-10 weeks.
Undergoing fertility treatments is less fun than a hangover. But they have one silver lining: Once pregnant, you receive information about your chances of a healthy pregnancy much earlier, from your “betas”–blood tests of your beta hCG (Human Chorionic Gonadotropin) levels.
Continue reading “An early beta hCG test does predict your risk of miscarriage”
Who needs prenatal testing for genetic disorders? How much does your risk of carrying a baby with a genetic disorder increase with your age? Which prenatal test or screen is right for you?
These are among the questions my amazing co-author Molly Dickens (and fellow pregnant scientist blogger/partner-in-crime) and I tackle in our new ebook on prenatal testing. We provide a quick “cheat sheet” on how these tests compare, and then dig into the nitty-gritty details of each as well as the history of prenatal testing and how to estimate your personal risk of carrying a baby with a genetic disorder.
Continue reading “Overwhelmed by prenatal genetic testing options? Download my ebook!”
Three years ago, sitting with my 15-month-old son and my husband during a long layover, on our way back home from Norway, I felt a sudden gush of warm blood.
So much for my miracle pregnancy, I thought. I was only six weeks along and certain I was miscarrying.
Our return trip was already off to a poor start. United Airlines had cancelled our original flight from Newark home to San Francisco. Then, to rub salt in the wound, they refused to refund our first-class tickets.
We never fly first class, but had made an exception for this trip. We were travelling overseas with my 15-month old son and facing a 9-hour jet lag. The chance of sleeping on route, we decided, was worth the extra cash. We had bought our tickets a year in advance to lower the cost.
But United, being United, told us we would have to request a refund, and then maybe they would grant it. And–perhaps just for kicks–they refused to let us access the first-class lounge while in Newark, because our replacement tickets were now in Economy.
My husband–who nevers argues with anyone behind a counter and hates it when I do–spent half an hour arguing with their “customer service” that they should give us passes to the first class lounge. After all, we had paid for first-class tickets even if we no longer had them. But no dice.
So there we were, exhausted and enraged. I had not slept in over 24 hours. My son, sick for the last 3 days with a high fever, had nursed continuously the entire flight from Oslo to Newark. And then I started bleeding.
At that point, I contemplated tweeting, “United, you ate my baby,” but decided against publicly sharing my pregnancy or what I assumed was an impending miscarriage.
The pregnancy had been a surprise, but a welcome one. We had taken over a year to conceive my son. This time we had not been trying. I was still breastfeeding, and my cycles had only resumed a month earlier. We were planning to wait a few more months and then start trying for #2, expecting that it could easily be another 6 to 12 months before we conceived.
The bleeding tapered off by the next morning. I had no pain or cramping, so little fear of an ectopic pregnancy. And I still felt pregnant: nauseated, tired, and lightheaded.
I called my OB, but they could not fit me in for another 5 weeks. Until then, they told me, just sit tight. Oh, and assume that I was still pregnant, because a miscarriage would have caused several days of heavy bleeding.
I found another OB.
My new OB ran tests. My HCG levels were normal, but my progesterone was low, perhaps because of the nearly constant breastfeeding, the lack of sleep, and the stress. She could not say for sure. She prescribed progesterone supplements for the rest of my first trimester.
Progesterone helps build up and maintain the uterine lining for implantation of the fertilized egg. High levels of progesterone are required to sustain an early pregnancy. But taking progesterone supplements during the first trimester to prevent a miscarriage is controversial.
Over half of miscarriages result from chromosomal abnormalities, and no amount of progesterone will save these pregnancies. A 2013 review of randomized trials, however, found that while progesterone supplements did not alter the risk of miscarriage for pregnant women as a whole, they did significantly lower the chances of miscarriages for women with 3 or more prior miscarriages.
And for women like me, with a threatened miscarriage (defined as any bleeding within the first 20 weeks of pregnancy), who have more than double the normal odds of a miscarriage*, progesterone supplements appear to cut the risk of miscarriage in half, and oral progesterone, as opposed to suppositories, may be especially effective.
So, although I will never know for sure, my OB may have saved my pregnancy.
A Subchorionic Hematoma
At that initial visit, she also performed an ultrasound. The fetal heartbeat was loud and clear, fast and reassuring, racing along like a rabbit’s. When I heard my baby’s heartbeat, I fully exhaled for the first time in days.
Less reassuringly, the ultrasound revealed a subchorionic hematoma–a blood clot next to the placenta and the cause of my bleeding.
Pregnancies with a subchorionic hematoma are considered high risk. They have a higher risk of miscarriage (17.6% versus 8.9%), stillbirth (1.9% versus 0.9%), and placental abruption (3.6% versus 0.7%). They have a slightly higher risk of preterm delivery (13% versus 10%) and for the waters breaking before labor starts (tv-style labor).
The risk varies by the location of the hematoma. Pregnancies with recurrent bleeding or with hematomas located between the placenta and the uterine wall (retroplacental hematomas) have a higher risk of miscarriage and other pregnancy complications like placenta abruption. Because of the risk of placental abruption, bleeding in the second and third trimesters require immediate medical attention.
As worrisome as these statistics sound, most subchorionic hematomas resolve on their own, as mine eventually did. By 11 weeks, we could no longer see the hematoma on an ultrasound. And thankfully, rest of my pregnancy was uneventful. I gave birth to healthy baby girl, who in a few months will turn 3.
Do you have a story of bleeding in early pregnancy? Was a cause detected, and how did things turn out?
Footnote
*About 20% of women experience bleeding during early pregnancy. Figuring out their chances of a miscarriage is far from simple.
One commonly cited statistic states that roughly 50% of these women eventually miscarry. Some digging reveals that this claim derives from a 1981 obstetrics textbook rather than recent research. (Lots of researchers cite papers that cite papers that cite this textbook, and I am willing to bet that none of them have read the original research behind this claim.)
If bleeding starts after detection of a normal fetal heartbeat, most prospective studies find a much lower rate of miscarriage, of 3.4-5.5%.
References
Haas DM, Ramsey PS. Progestogen for preventing miscarriage. Cochrane Database of Systematic Reviews 2013, Issue 10. Art. No.: CD003511. DOI: 10.1002/14651858.CD003511.pub3.
Nagy S, Bush M, Stone J, Lapinski RH, Gardó S. Clinical significance of subchorionic and retroplacental hematomas detected in the first trimester of pregnancy. Obstet Gynecol. 2003 Jul;102(1):94-100.
Sotiriadis A, Papatheodorou S, Makrydimas G. Threatened miscarriage: evaluation and management. BMJ : British Medical Journal. 2004;329(7458):152-155.
Trop I, Levine D. Hemorrhage during pregnancy: sonography and MR imaging. AJR Am J Roentgenol. 2001 Mar;176(3):607-15.
Tuuli MG, Norman SM, Odibo AO, Macones GA, Cahill AG. Perinatal outcomes in women with subchorionic hematoma: a systematic review and meta-analysis. Obstet Gynecol. 2011 May;117(5):1205-12. doi: 10.1097/AOG.0b013e31821568de.
Pregnancy can be cruel. Just when you are at your most swollen, bloated, and exhausted, sleep proves frustratingly elusive. Every night, you toss and turn, trying to find a comfortable position, your back aching, and your belly pressing down on your bladder. And then, as you finally start to drift off, you realize you need to pee.
To make matters worse, despite having an enormous bowling ball attached to your stomach, you are told you cannot sleep on your back:
“After 16 weeks of pregnancy, experts advise women to not sleep on their backs, but rather should lie on their sides, ideally the left side” states a popular pregnancy blog.
But who came up with this idea?
This advice stems three studies that have linked back sleeping with late stillbirth (pregnancy loss after 28 weeks). (Interestingly these warnings predated the three studies, so they are not exactly the reason women are told to avoid back sleeping)
I described the first two studies, one conducted in Ghana, the other in New Zealand, in an earlier post, and concluded that not only did they provide no reason for alarm, they certainly do not justify blanket advice again back sleeping.
In 2015, a third study came out linking back sleeping with late stillbirth. Does it change the overall picture?
Continue reading “Back Sleeping During Pregnancy and the Sydney Stillbirth Study”
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:
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”
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”
Getting pregnant is a numbers game. Here’s what every woman should know about her odds of success in her late 30s and early 40s.
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”
Can you safely sleep on your back while pregnant? Here’s what the latest research has to say.
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.
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 (which you can obtain by propping up your right side with a pregnancy pillow or a regular pillow) has been shown to reduce the risk of low blood pressure.
For me, sleeping in with my right side slightly propped up felt pretty safe. But mostly, it felt comfortable.
Did you avoid lying on or sleeping on your back during pregnancy?
