What medication is used off-label to prevent preterm birth?

Progesterone injections are utilized off-label to help prevent preterm birth, particularly in women who have a history of premature labor or who are at high risk for preterm delivery. The rationale behind using progesterone for this purpose is based on its role in maintaining pregnancy and inhibiting uterine contractions. By providing supplemental progesterone, it can help sustain the uterine lining and reduce the likelihood of early contractions, which is critical for maintaining pregnancy to full term.

This use of progesterone is supported by research indicating that women who receive progesterone injections during the second trimester have a reduced risk of preterm birth, especially in cases of cervical insufficiency or a history of preterm deliveries. The clinical guidelines recommend this intervention in specific populations to optimize maternal and fetal outcomes.

In contrast, other medications listed serve different purposes. For instance, betamethasone is a corticosteroid primarily used to accelerate fetal lung maturity in the event of anticipated preterm delivery, rather than for prevention. Magnesium sulfate is typically used as a neuroprotective agent for the fetus in the case of imminent preterm labor or to prevent complications such as preeclampsia. Terbutaline, a beta-agonist, can be used for short-term management of preterm