Are medications that inhibit uterine contractions harmful to the fetus?

Medications that inhibit uterine contractions, when used correctly, typically have no adverse effects on the fetus.

Drugs that suppress uterine contractions are commonly used to treat preterm labor, control the progress of labor, or manage pregnancy-related complications. These medications include, but are not limited to, magnesium sulfate, beta-receptor agonists such as ritodrine, calcium channel blockers, and atosiban. Although their mechanisms of action vary, their shared goal is to prolong pregnancy, thereby providing the fetus with more time to mature. These medications are primarily intended to prevent complications arising from preterm labor or excessive uterine contractions.

Fetal effects: The safety profiles of most uterine contraction inhibitors during pregnancy are considered relatively favorable. For example, magnesium sulfate is widely used for the prevention of preterm birth and reduction of the risk of neonatal brain injury, and its short- and long-term fetal safety is supported by extensive research.

However, prolonged and excessive use of magnesium sulfate during late pregnancy may lead to reduced fetal bone density and increased risk of fractures in the fetus or newborn. Prostaglandin synthase inhibitors may have subtle adverse effects on the fetus and newborn when used during late pregnancy.

These medications should be used only under the guidance of a qualified physician.