- Kenny Lin, MD, MPH
Maternity care providers have traditionally prescribed "bed rest," or activity restriction, for a host of pregnancy complications (including preterm contractions, short cervix, multiple gestation, and preeclampsia) despite evidence that it does not improve maternal or neonatal outcomes. On the other hand, prolonged activity restriction in pregnancy increases risk for muscle atrophy, bone loss, thromboembolic events, and gestational diabetes. Although it did not include this practice in its Choosing Wisely "Five Things Physicians and Patients Should Question" list, the Society of Maternal and Fetal Medicine (SMFM) recently published a strongly worded position paper recommending against activity restriction in pregnancy for any reason.
This isn't the first time reviewers have examined the evidence for activity restriction and found it lacking; a 2013 summary of several Cochrane reviews of therapeutic bed rest in pregnancy also found such poor data to support the practice that the authors concluded its use should be considered unethical outside of the context of a randomized controlled trial.
The message isn't getting through to physicians or patients, though. A 2009 survey of SMFM members found that 71 percent would recommend bed rest to patients with arrested preterm labor, and 87 percent would advise bed rest for patients with preterm premature rupture of membranes at 26 weeks gestation, even though most of them did not believe it would make make any difference in the outcome (the most common answers were "minimal benefit" and "minimal risk"). Unfortunately, the risk may be more than minimal. Not only does activity restriction expose pregnant women to harm, a secondary analysis of a randomized trial of preterm birth prevention found that nulliparous women with short cervices whose activity was restricted were actually more likely to deliver before 37 weeks' gestation than those who were not.
Similarly, a search of the terms "bed rest" on popular pregnancy websites Babyzone and Pregnancy.org yielded the following statements that fly in the face of evidence: "Changing the force of gravity usually helps minimize preterm labor." "It [bed rest] helps keep blood pressure stable and low." "In most cases, bed rest is used to help the body have the best chance to normalize." A handout on WebMD provided a more balanced assessment:
Bed rest has been a way of treating pregnancy complications for more than a hundred years. But there's a problem. While bed rest is a common treatment, there's no proof that it helps. It doesn't seem to protect your health or your baby's. In fact, bed rest has risks itself. Doctors still prescribe it, but more because of tradition than good evidence that it works.
The handout went on to advise patients to question their physicians closely or get a second opinion if bed rest is recommended. That's sensible advice. Physicians who are reluctant to abandon this useless and potentially harmful maternity practice should consult the SMFM paper or the American Family Physician By Topic collections on Prenatal Care and Labor, Delivery, and Postpartum Issues, where no articles recommend activity restriction for pregnancy complications.