Birth before the 37th completed week of pregnancy is considered preterm. About 10% of pregnancies end early. In the United States, preterm birth rates declined to 9.54% between 2007 and 2014 but have increased since.
Preterm birth is the leading cause of injury and death to babies and may affect the long-term health and well-being of the child. Some of the known risk factors for preterm labor and birth include the mother’s age (either very young or older), smoking tobacco, low income, either being very thin or extremely overweight, chronic medical problems, anomalies of the uterus, multiple gestation (twin, triplets, or more), and infection, as well as others. However, researchers considered the two most important risk factors to be previous preterm birth and having a short (< 2.5 cm) cervix, possibly because those risk factors can be addressed medically.
Multiple medical treatments were evaluated to prevent premature birth. Tocolytic agents – drugs that suppress uterine contractions – aren’t effective in preventing preterm birth, but rather only delay delivery allowing time for transfer to an appropriate environment if necessary and to administer steroids. Glucocorticoids (steroids) can speed the development of a premature baby’s lungs and are often administered during preterm labor.
The investigators concluded that both cervical cerclage and vaginal progesterone should be considered to prevent preterm birth in singleton pregnancies with shortened cervix and previous history of preterm birth.
Cervical cerclage is a surgical procedure that requires anesthesia, is associated with more risks (injury, rupture of membranes, infection), and is more likely to be associated with the need for cesarean section. vaginal progesterone is equally effective for preterm birth prevention and is associated with fewer side effects/complications. Direct comparison of the two methods and the use of their combination require further evaluation.