Tocolysis

Excerpt

Tocolysis is an obstetrical procedure carried out with the use of medications with the purpose of delaying the delivery of a fetus in women presenting preterm contractions. These medications are administered with the hope of decreasing fetal morbidity and mortality. Tocolysis is intended to prolong gestation for two to seven days and works by creating a quiescent environment in the uterus. This is important to allow transportation to a higher care facility, to administer a fetal lung maturity scheme with antenatal corticosteroids, and the additional time is also used to determine the group B streptococcus (GBS) status of the pregnant woman, and provide prophylaxis if she is either positive or the GBS culture status is unknown.

Tocolysis is not intended to increase gestation of the fetus to term but is focused on providing a window of time to support treatments that have been shown to improve outcomes for delivery. Currently, there are no United States Food & Drug Administration (FDA) approved medications for tocolysis. All medications are administered as off-label indications. However, these medications are still effective and should be used when clinically indicated. Historically, ritodrine and terbutaline had been approved for maintenance tocolysis. Ritodrine had been approved in 1977 but was removed by the FDA due to increased maternal mortality due to cardiovascular complications, is still used as a tocolytic internationally but has been associated with pulmonary edema. Terbutaline was suggested in 1987 as a continuous infusion pump for maintenance tocolysis as well but was removed in 2011 and changed from a Pregnancy Class B to a Class C drug.