In a new guideline, the Society for Maternal-Fetal Medicine has recommended against the routine use of bed rest in pregnancy.
"There is no evidence that bed rest improves outcomes", says Anthony Sciscione, DO, director of Delaware Center for Maternal and Fetal Medicine and one of the co-authors of the guideline. "However, there is evidence that bed rest can be harmful for moms, babies, and families."
About one in five women are placed on bed rest during their pregnancy. Surveys have shown that both ob/gyns and maternal-fetal medicine specialists prescribe activity restriction and bed rest, even though most of the physicians surveyed do not expect that doing so will actually improve pregnancy outcomes.
Restriction of activity in pregnancy is also known as "bed rest," or "modified bed rest" and has been recommended for a number of potential complications such as preterm (before 37 weeks gestation) contractions, a dilated cervix from preterm labor, a short cervix, preterm premature rupture of membranes (water breaking before 37 weeks gestation and before the onset of labor), elevated blood pressure, preeclampsia, inadequate growth of baby, placenta previa, risk of miscarriage, multiple gestations (e.g. twin pregnancies), and others.
In the guideline, the Society points out that bed rest has not been shown to reduce the chance of preterm delivery in women either at risk or already experiencing preterm labor. One study found that preterm birth was more common in women already at risk of preterm birth when they were placed on any type of work or non-work related activity restriction, both at home and in the hospital. There is also no data indicating that activity restriction is of benefit for any obstetric condition.
Inadequate growth of the baby is often attributed to problems with blood flow to the placenta and activity restriction or bed rest is often prescribed in an effort to improve placental blood flow. Again, studies fail to show a benefit to this practice.
While there is no evidence the bed rest improves outcomes, there are several potentially harmful side effects. It's widely known though that extended periods of activity restriction can result in muscle and bone loss. This "deconditioning" happens to pregnant and non-pregnant individuals. Changes can occur after only a few days of immobility and there is not a lot of information on the full impact these changes have in pregnant women.
Bed rest may also increase risk of developing blood clots in the legs (deep venous thrombosis, or DVT) and movement of clots to the lungs (pulmonary embolism, or PE). Such clots are more common among pregnant women, and limiting physical activity may compound these risks.
Lack of movement may also increase a woman's risk of gestational diabetes, or GDM. The Society notes that being admitted to the hospital for pregnancy-related complications has been associated with a higher risk of GDM, although more studies are needed. Elevated levels of blood sugar commonly occur in non-pregnant patients placed on activity restriction.
In addition to the potential negative physical effects associated with activity restriction during pregnancy, there is also an increased risk of anxiety and depression, adverse psychological effects on the family, loss of income, and lower birth weights.
In summary, the Society for Maternal-Fetal Medicine notes that the practice of activity restriction or bed rest has very little evidence to support a benefit for mother or infant, but has well-described negative effects on the mother, newborn and the family.