Lori Gray was 27 weeks into her pregnancy and working full time as an elementary school teacher when she received the bad news. During a routine prenatal check, her doctor informed her that her levels of amniotic fluid were high and placed her on strict bed rest.
Gray hated the idea of leaving work, but her concern for the baby was paramount. On doctor's orders, she immediately settled into a daily routine of near complete inactivity.
"The only thing I did for three weeks was walk to the bathroom and the refrigerator," she recalls. "My mother-in-law flew into town and did everything for my husband and me."
Each year in the United States, bed rest is prescribed for hundreds of thousands of pregnant women considered to be at increased risk for preterm delivery. The use of bed rest is based on two important assumptions: that it is effective in prolonging pregnancy and that it is harmless. Both assumptions are largely unsubstantiated.
"The scientific evidence in support of bed rest is weak," says Dr. Thomas Goodwin, director of maternal fetal medicine at USC's Keck School of Medicine. "It's not science with a capital S."
The reason that bed rest is almost universally recommended for women who go into preterm labor is that physical activity is directly related to uterine activity.
"When you're more active, you have more uterine contractions," Goodwin says. But bed rest doesn't appear to produce the expected results. Guidelines released in 2003 by the American College of Obstetricians and Gynecologists acknowledge that it does not improve rates of preterm birth in these women and caution against its routine use in the treatment of preterm labor.
Bed rest is also commonly prescribed to prevent the development of preterm labor in women who are considered "at-risk." Many doctors routinely place patients carrying more than one baby on bed rest during the last few weeks of pregnancy. They also widely use it to treat women thought to have an incompetent or weakened cervix, women suffering from pregnancy-related high blood pressure and women whose babies aren't growing as well as expected. Abnormal levels of amniotic fluid -- whether too high or too low -- can also trigger a prescription for bed rest, as in Gray's case. And so can abnormalities in the placement or attachment of the placenta.
Whether or not bed rest is actually effective in any of these situations is largely unknown because, unfortunately, the studies simply haven't been done.
Some obstetricians make the case that women have very little to lose (and potentially a baby to save) by going on bed rest. Others, however, argue that significant restrictions in activity can take a physical, financial and emotional toll on women and their families.
Inactivity weakens muscles -- women on bed rest tend to lose strength and stamina. This atrophy occurs not just in skeletal muscles but those throughout the body, including the heart muscle. Bones, which are strengthened through regular use, deteriorate as well.
Bed rest limits a woman's ability to work and care for her family. For some women, leaving a job can be financially devastating. For others, the inability to help at home is most challenging.
Many women find being stuck at home frustrating and isolating.
"There was a part of me that thought it would be kind of nice to be on bed rest and have people cater to me," Gray says. "It wasn't! I felt helpless."
In spite of its unproven effectiveness, many doctors continue to advocate bed rest because they simply don't know what else to do. There are not a lot of useful therapies for the prevention and treatment of preterm labor. Medications called tocolytics are perhaps the most effective way to stop preterm labor once it has started, and they have been found to prolong pregnancy by only two to seven days.
"For things to change, there needs to be a positive direction to change in," Goodwin says.
Some new tools are being used to help identify women at greatest risk of giving birth to their babies preterm and who thus are most likely to benefit from intervention. One involves a test for fetal fibronectin, a protein that attaches the fetal sac to the lining of the uterus. The presence of fetal fibronectin in cervical or vaginal secretions at 5 1/2 to 8 1/2 months of pregnancy signals an increased risk of preterm delivery. (A negative test means that the likelihood of delivering in the following two weeks is very low.)
Ultrasounds of the cervix are also helpful. Abnormal shortening of the cervix is a sign that a woman will deliver preterm.
"If the cervix isn't shortening, chances are the baby is going to stay in place," Goodwin says.
Three weeks after settling into her sedentary routine, Grey gave birth to a beautiful -- but 10 weeks premature -- baby boy, Wyatt, who spent the first eight weeks of his life in the neonatal intensive care unit. Now 8 months old, Wyatt is doing great.
"Would things have been different if I hadn't gone on bed rest?" Gray asks. "Would I have delivered even sooner?" No one knows the answer to those questions yet.
Dr. Valerie Ulene is a board-certified specialist in preventive medicine practicing in Los Angeles. She can be reached at email@example.com. The M.D. appears the first Monday of the month.