Researchers at the Eunice Kennedy Shriver National Institute of Child Health and Human Development, Perinatology Research Branch, National Institutes of Health, Department of Health and Human Services published a paper stating that Nifedipine, a calcium channel blocker used to lower blood pressure, is a useful tocolytic (anti-contraction) medication for the management of preterm labor.

Nifedipine is a cardiac medication. It works by relaxing the smooth muscle of the heart so that it is not pumping so hard. This relaxation allows for more blood to flow through the heart and to the rest of the body, providing more blood, nutrients and oxygen to the body. Because the muscles of the heart are relaxed and there is more oxygen available and delivered to (cardiac) cells, chest pain is relieved. Just as Nifedipine relaxes smooth muscles in the heart, it also relax smooth muscles of the uterus slowing or halting contractions and avoiding preterm labor and delivery.

When Nifedipine was given to pregnant women experiencing preterm labor, the women (actually their infants) had significantly reduced incidences of respiratory distress syndrome,  necrotizing enterocolitis, intraventricular hemorrhage, neonatal jaundice, and admission to the neonatal intensive care units. Nifedipine was  also associated with a significant reduction in the risk of delivery within 7 days of initiation of treatment and before 34 weeks’ gestation. Mamas also experienced fewer adverse side effects compared with Beta Adrenergic Receptor Agents and Magnesium Sulfate.