Your doctor's suggestion is a good one. It's consistent with the most recent recommendations from the National Institutes of Health (NIH) and the American Congress of Obstetricians and Gynecologists (ACOG).
If you're between 24 and 34 weeks pregnant and likely to deliver a premature baby in the next week, both the NIH and ACOG recommend a single course of corticosteroids. (This is a type of steroid that crosses the placenta better than other types.) Steroids help speed up the development of your baby's lungs and some other organs, which greatly increases his chances of survival.
In a 2000 report, a panel of NIH experts studied the effects of injecting pregnant women with a single course of corticosteroids when they were in preterm labor and found that it significantly lowered the risk of infant death. The babies whose moms received this treatment were also much less likely to suffer respiratory distress syndrome and bleeding in the brain.
Corticosteroid treatment has also been shown to lower a premature baby's risk of a potentially life-threatening intestinal disease, necrotizing enterocolitis. And other studies that followed children for up to 12 years have found no adverse neurological or developmental effects in those whose mothers received a single course of corticosteroids during pregnancy.
In most cases, unless you're enrolled in a clinical trial, you won't be given a repeat course of corticosteroids in preterm labor. Your practitioner may consider giving you another dose, however, if your last treatment was more than two weeks ago, you're still less than 33 weeks pregnant, and you're likely to deliver within the next seven days.
Corticosteroids are beneficial for preterm babies, but even a single dose of steroids may have some short-term adverse effects on you. Although it doesn't happen often, corticosteroids can raise your blood sugar to levels that require you to take insulin for a little while even if you don't have diabetes. If you do have diabetes or gestational diabetes, being given corticosteroids may require you to increase your insulin dosage.
Another uncommon effect of corticosteroids occurs when they're combined with other medications (specifically, tocolytics) to stop preterm labor. In this combination, they can raise your risk of developing pulmonary edema, a condition in which fluid builds up in your lungs. If you're taking both tocolytic medications and corticosteroids, you'll need to be watched especially carefully even though the risk of pulmonary edema is still pretty low.
Corticosteroids appear safe for moms in the long term, and with few exceptions, the benefits are thought to outweigh any possible problems.