Use of vaginal progesterone is not associated with a reduction in recurrent preterm birth, according to a study published in JAMA Network Open.

David B Nelson, MD, from the University of Texas Southwestern Medical Center in Dallas, and colleagues evaluated the association of vaginal progesterone treatment with prevention of recurrent preterm birth among patients with a singleton pregnancy.

The analysis included 417 patients who initiated treatment between 16 weeks and zero days and 20 weeks and six days of pregnancy until 36 weeks and six days of pregnancy or delivery and matched (3:1) untreated historical controls.

The researchers found that the overall rate of recurrent preterm birth was 24.0% for the progesterone cohort versus 16.8% expected in the matched historical controls.