Back Sleeping During Pregnancy and the Sydney Stillbirth Study

Pregnancy can be cruel. When you’re 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. Just as you finally start to drift off, you realize you need to pee.

And then, to add insult to injury, you read this:

“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.” – mamalette

Pregnant women are often warned against sleeping, even lying on their backs while pregnant, but with little scientific justification.

The current alleged basis of this advice is the 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?

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Don’t Count on Breastfeeding to Help You Shed Your Baby Weight

Breastfeeding melts off the baby weight, right? Or so we are told. Breastfeeding leads to an “earlier return to prepregnancy weight,” according to the American Academy of Pediatrics (AAP).

This is because “breastfeeding burns extra calories, so it can help you lose pregnancy weight faster,” as many popular websites, like WebMd claim.

Sounds pretty clear cut, right?

So when I failed to lose weight while breastfeeding my first child, I was shocked. Weren’t those pregnancy pounds supposed to practically fall off? Why were my pre-pregnancy jeans still relegated to the back of my closet?

Breastfeeding an infant does burn an average of 480 calories a day. So why wasn’t I losing more weight?

But like so many other alleged benefits of breastfeeding, breastfeeding-aided weight loss turns out to be vastly overblown.

In other words, my experience was completely normal. For most well-nourished women, long-term breastfeeding results in only a trivial amount of extra weight loss by 6 months postpartum, usually only of 1-2 lbs.

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Questioning Breastfeeding’s Benefits Does Not Make Me Anti-Breastfeeding

Earlier this week, I wrote about the alleged benefits of breastfeeding being vastly overstated.

My goal in writing that post was not to nurse some long-standing grudge against breastfeeding advocates. Nor was it an attempt to justify my own parenting choices: I breastfed both my children for well over a year.

(And yes, as some readers have inquired, I know just how wonderful breastfeeding can be. How breastfeeding your baby can be calming and joyful, even magical. But whether I found breastfeeding magical or a chore–or, in actuality, both–has nothing to do with whether it lowers the risk of asthma, or heart disease, or anything else.)

In response to my post, someone shared this comment on Facebook:

“Anyone who thinks this [my post] a solid piece of work needs to read my latest book, Milk Matters: infant feeding and immune disorder. No one has to prove that breastfeeding (the evolutionary and physiological norm that provides free stem cell transplants) makes a positive difference. Those who assume, claim or promote artificial feeding as safe or adequate need to prove that deviating from such basic physiological norms is safe, that there are no short or long term harms from doing so. …”

I am sharing this comment not because I find it particularly compelling, but because I think it nicely illustrates the problem with arguments made by many breastfeeding advocates: They start with the assumption that breast is best. And then, inevitably, they fail to scrutinize the evidence, no matter how flimsy, that supports that assumption.

And the evidence is flimsy indeed. Most of the alleged benefits of breastfeeding are found only in observational studies, which are widely acknowledged as biased. On average, breastfeeding mothers have a higher levels of education, higher incomes, and live in safer neighborhoods than formula-feeding mothers, granting their children an early leg up in life. Separating the effects of breastfeeding from these other advantages is next to impossible.

How do we know that these observational studies are biased? Primarily because we do not find the same benefits in better-designed studies–sibling comparison studies and the PROBIT randomized controlled trial. The only clear-cut benefit seen in these studies is a lower risk of severe vomiting and diarrhea during infancy. (For a detailed summary, see my earlier post).

To be fair, breastfeeding advocates are right, in a way. Breastmilk does contains numerous hormonal, antimicrobial, immunological, and nutritional factors not found in formula. This is why breastmilk helps protect against vomiting and diarrhea during infancy.

Before the advent of clean water, sanitation, and modern medicine, breastfeeding was frequently life-saving. In countries where access to these resources remains limited, it still is. There’s no bigger possible benefit than survival.

But these beneficial properties do not imply that breastmilk has any long-term benefits for the panoply of modern ailments: allergies, asthma, obesity, type 2 diabetes, and cardiovascular disease. We cannot claim such long-term benefits without sound empirical evidence. And that is entirely lacking.

If the U.K’s National Health Service, the American Academy of Pediatrics, and others were to say, “We recommend breastfeeding because it reduces the risk of severe diarrhea and vomiting during infancy, and because breastmilk contains unique immune, hormonal, and nutritional factors not found in formula, the long-term benefits of which are unknown,” I would have no problem with their claims.

But instead, they have chosen to present poor quality evidence as fact. Playing fast and loose with the evidence in this way undermines their credibility. Worse, it violates the trust that women have placed in them.

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Breastfeeding Benefits: The Real, the Imagined, and the Exaggerated

A good friend of mine living in Scotland, who had a baby last year, mentioned to me how disappointed he has been with the U.K. National Health Service’s promotion of breastfeeding. Calling the alleged benefits overstated, he said, is itself an understatement.

I nodded in general agreement, acknowledging that many of the alleged benefits of breastfeeding have only been found in observational studies. 

Observational studies on breastfeeding merit skepticism, because they all suffer from the same major problem: breastfed infants on average differ from formula-fed infants not just in how they are fed in infancy, but in practically every other possible way–maternal education, maternal IQ, poverty, neighborhood safety, exposure to environmental toxins, race, and type and quality of childcare. In scientific terms, breastfeeding is confounded, out the wazoo.

We cannot tell which benefits found in an observational study derive from breastfeeding rather than from the myriad other advantages linked with breastfeeding.

(The “good” observational studies attempt to control statistically for the other relative advantages of breastfed infants. Unfortunately, controlling for confounds only works well when (1) all the important potential confounds are known, and (2) when there is a fair amount of overlap between the groups being compared. Neither of which is true when it comes to breastfeeding.)

In an ideal world, we would settle this question by conducting several large randomized controlled trials (RCTs), in which new mothers would be randomly assigned to breastfeed. RCTs are the gold standard in medicine for determining whether a true cause and effect relationship exists. In practice, though, such trials are neither feasible nor ethical.

Fortunately, we have the next best thing: a handful of studies that have cleverly circumvented the problem of confounding. These fall into two categories:

  • sibling studies, which compare siblings from the same families who were breastfed for different lengths of time, or who were not both breastfed.
  • a large RCT of a highly successful breastfeeding intervention (PROBIT Trial).

(Is the PROBIT Trial an exception to the no-RCT rule? No. Women in the PROBIT trial were not randomly assigned to breastfed or not; they were randomly assigned to receive a breastfeeding intervention or not.)

After my friend and I spoke about his irritation with the U.K.’s National Health Service (NHS) overstating the benefits of breastfeeding, I was dissatisfied with my vague sense that he was right. I wanted to know exactly which benefits had been oversold and exactly which were supported not just by observational studies but by better-designed studies.

The short answer: Nearly all the alleged long-term benefits are likely the result of confounding, not breastfeeding. Better-designed studies find only a handful of real benefits: a reduced chance of severe gastrointestinal infections and a lower risk of eczema during infancy, and perhaps a small boost in childhood IQ.

Alleged Breastfeeding Benefits According to the NHS

According to the NHS, breastfed infants are…

  • less likely to suffer from vomiting or diarrhea and therefore less likely to go to hospital
  • less likely to develop type 2 diabetes in later life
  • less likely to become obese in later life
  • less likely to suffer from heart disease in later life
  • less likely to suffer from constipation
  • less likely to get a chest or ear infection and therefore less likely to go to hospital
  • less likely to suffer from tooth development problems
  • more likely to have good communication and speech skills
  • more likely to have good circulation
  • less likely to suffer from wind, colic and constipation
  • less likely to develop eczema or asthma

Sounds pretty impressive, right? Until you set aside the evidence from observational studies…

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Blood-Based Tests of Fetal Sex: Are They Accurate?

Many expectant parents are impatient to learn if they are having a boy or a girl. So they may be attracted to new companies, like SneakPeek, which claim to be able to determine your baby’s sex with 99% accuracy early in the first trimester, with only a simple blood draw.

These new tests rely on what is known as cell free fetal DNA (cffDNA)–small fragments of DNA shed from the placenta into your bloodstream.

Unfortunately, according to a 2011 meta-analysis published in JAMA, some of these companies overstate the accuracy of their tests. The meta-analysis found that none of these cfDNA-based tests are accurate before 7 weeks. (The meta-analysis also examined urine-based tests. None of these were accurate.)

Between 7 and 20 weeks, accuracy for these blood-based tests ranged from 95-98%, depending on the specific techniques employed and the baby’s actual sex. (The tests were more accurate when they use a DNA amplification technique known as real-time quantitative polymerase chain reaction.) Only after 20 weeks were the blood-based tests 97-99% accurate.

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Some Tips for Finding the Right Nanny

Finding the right caregiver for your baby has to be one of the most stressful experiences as a new parent.

To make the prospect a little less daunting, I’d like to share some tips I sent to a friend back when she first started looking for a nanny.

1. Start looking for a nanny at most 1-2 months before you need her to start. Most nannies are looking to start work immediately or within a few weeks of starting their search. Unless you are willing to pay someone to hold them, or know someone who has a great nanny and is planning to let them go because of a move, finances, and so on., I would wait until close to the time you need them to start.

2. Parenting groups and word of mouth are the best ways to find nannies. Local parenting listservs are a great place to find excellent caregivers, because people who love their nannies will often help them find their next position.

When reading through posts about potential nannies, you should prioritize those that are posted by employers, as opposed to the nanny herself, and those that are genuinely glowing.

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Nine Science-Backed Tips for Getting Pregnant Quickly

Back when my husband and I decided to try for a baby, I remember feeling so impatient. I basically wanted a baby right then. Today. That instant. The inevitable nine months seemed too long to wait, let alone the time it would take for us to conceive.

I am sure I am not alone in this sentiment.

So, if you too are feeling impatient to become pregnant, here are some science-based tips to help maximize your chances.

1. Have sex at the right time. Timing intercourse correctly is the most important thing you can do to conceive quickly. Continue reading

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Fall is Here! Time to Get a Flu Shot

It’s the official start of fall, my favorite season. The leaves are beginning  to turn into their brilliant fall mélange of gold and orange and crimson. The morning air has taken on a new welcome crispness, filled with the fresh scent of leaves underfoot. It’s the time of hot spiced apple cider, pumpkin carving, and hay rides.

And just about time to get your seasonal flu shot.

Wait, maybe that was not part of your fall plans? Here’s why you should add it to your seasonal to do list, along with securing costumes for Halloween.

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Age and the Risk of Miscarriage

As women, we hear a lot about the difficulty of getting pregnant as we age, but staying pregnant can often be the bigger challenge, especially as our fertility begins to wane.

The risk of miscarriage rises as a woman ages, with a dramatic rise starting after age 37, with the steepest increase occurring after age 40. By age 45, less than 20% of all recognized pregnancies are viable.

The man’s age matters too. Having a partner over the age of 40 significantly raises the chances of a miscarriage.

Over half of miscarriages are caused by genetic abnormalities. As women age, chromosomal defects in their eggs become increasingly common. On average, a woman in her early 20s will have chromosomal abnormalities in about 17% of her eggs; this percentage jumps to nearly 80% by a woman’s early 40s. And as men age, chromosomal defects and point mutations–changes to a single nucleotide in their DNA–become increasingly common.

How The Chances of Miscarriage Vary By Age Continue reading

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Bedsharing and SIDS: Why I Chose to Bedshare with My Second Child

My second baby slept in bed with me, all night, every night, from the time we took her home from the hospital until she was 3 months old. At first, I was almost too terrified to fall asleep, for fear that I would roll over and suffocate her.

After all, nearly all major medical organizations warn against bedsharing, on the grounds that it increases the chances of Sudden Infant Death Syndrome (SIDS).

“The safest place for your baby to sleep is in the room where you sleep, but not in your bed. Place the baby’s crib or bassinet near your bed (within arm’s reach). This makes it easier to breastfeed and to bond with your baby,” according the The American Academy of Pediatrics.

Statements like these sound definitive. But, in fact, considerable scientific controversy surrounds the role of bedsharing in SIDS.

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