For a year and a half after giving birth to my third child, a full night’s sleep eluded me like some kind of impossible dream. In retrospect, it is clear that I was suffering from chronic insomnia, and it persisted long after my daughter had started sleeping through the night.
Sleep researchers define chronic insomnia as difficulty falling asleep or staying asleep that persists for at least 3 months. Chronic insomnia may affect as many as 1 in 6 adults in the U.S., and, as will surprise no one, it is especially common among new mothers.
Whether I was exhausted or well rested, every night, I would lay awake from 2 or 3 am until 5:30 am, running over my problems in the most negative possible light, and despising myself for being unable to fall back asleep.
Then, at dawn, I would finally fall into a deep sleep, only to have to awaken an hour or so later.
The effects on my ability to function were severe: My nerves felt constantly frayed, my patience was thin, and my mind felt like it was encased in cotton. Overall I felt like I was constantly running on empty, pushing myself to get through my day.
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.
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
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.
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.
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.