From 28 weeks of pregnancy on, go to sleep on your side, left or right, and don't go to sleep lying on your back

Cost

Free. The hard part is that people used to sleeping on their backs have to change position.

What you get

Stillbirth here means the baby dying in the womb after 28 weeks of pregnancy. A pooled analysis combined the individual data from five studies. Four were in New Zealand, Australia and the UK, and one was an international online survey. There were 851 pregnant women with a stillbirth, and 2257 pregnant women with normal babies as controls. The studies asked afterward how they had been going to sleep recently. Compared with going to sleep on the left side, going to sleep on the back had a stillbirth risk of aOR 2.63 (95% CI 1.72–4.04, the plausible range), about 2.6 times. Going to sleep on the right side was aOR 1.04 (0.83–1.31), no different from the left. The association was about the same for small babies, for obese pregnant women and for smokers. The authors estimated that if all pregnant women went to sleep on their sides after 28 weeks, stillbirths in this period could be about 5.8% lower (3.2%–9.2%). The UK's National Health Service (NHS) lists “not going to sleep on your back after 28 weeks of pregnancy” as one of the ways to lower the risk of stillbirth. It also says not to worry if you wake up on your back; just roll back onto your side and go back to sleep.

Notes

A dispute. All the figures above come from recall after the fact. Pregnant women whose baby died may not remember accurately, and the authors admit this themselves. There is also no randomized trial. A U.S. study asked 8706 women pregnant with a first baby about their sleeping position ahead of time and then looked at the outcomes. Up to 30 weeks of pregnancy, sleeping on the back or not on the left side had no association with stillbirth, a small baby or high blood pressure in pregnancy (aOR 0.99, 0.89–1.11). But it only followed up to 30 weeks, and sleeping position in the weeks after was not recorded. Sleeping on your side costs nothing and does no harm, so the UK advises it anyway. Stillbirth itself is rare; in high-income countries late stillbirth is about 1.3 to 8.8 per 1000 births. The size of the benefit is rated “large” by mechanically applying the 2.6 times; the reasoning is in the verification record. The benefit falls on the baby.

Evidence grade

B : Supported by research but without a precise number, or based on small or single studies.

Sources

1. Cronin RS, Li M, Thompson JMD, et al. (2019). An Individual Participant Data Meta-analysis of Maternal Going-to-Sleep Position, Interactions with Fetal Vulnerability, and the Risk of Late Stillbirth. EClinicalMedicine, 10, 49-57. https://doi.org/10.1016/j.eclinm.2019.03.014
2. Silver RM, Hunter S, Reddy UM, et al. (2019). Prospective Evaluation of Maternal Sleep Position Through 30 Weeks of Gestation and Adverse Pregnancy Outcomes. Obstetrics and Gynecology, 134(4), 667-676. https://doi.org/10.1097/AOG.0000000000003458（备注里的反方研究）
3. NHS. Stillbirth. https://www.nhs.uk/conditions/stillbirth/

Translated from the Chinese original. Original book, section 27, tip 19. This section is about health and medicines. It is general information, not a substitute for a doctor’s diagnosis or prescription. Content may be out of date and rules differ by place. When you actually deal with an agency, a doctor or a court, follow what local officials, doctors and lawyers tell you. Disclaimer