Progesterone does not prolong pregnancy after PPROM

We all know the familiar scene in the movies: our favorite pregnant character is busy grocery shopping when suddenly, a puddle of clear water forms around her feet. Her water broke! Cut to the next scene and she is holding a peaceful pink infant in her arms with a lullaby tinkling in the background. In the real world, things are not so simple. 

In fact, when the bag of water breaks before labor starts, we have a term for it: "PROM" or premature rupture of membranes. If PROM occurs before 37 weeks, or preterm, we call it "PPROM" or preterm premature rupture of membranes. When PPROM occurs before 34 weeks, we all cross our fingers that labor will not start and that the baby has a little more time cooking.

Over the years, researchers have tried to find a way to prolong pregnancy in the case of PPROM, trying things like antibiotics, for instance. In the latest article on attempts to prolong pregnancy after PPROM before 34 weeks, authors from an obstetrics group called Obstetrix, Mednax National Medical Group, led by Dr. C. Andrew Combs, undertook a well-designed study examining progesterone for this purpose.

The design of the study was rigorous: a multicenter, double-blind, placebo-controlled, randomized clinical trial. 154 women with PPROM between 23 weeks and 30 weeks & 5 days pregnant signed up to participate in the study. The authors gave half the women a weekly shot of progesterone, called 17-hydroxyprogesterone caproate, and the other half of women a fake or placebo shot weekly after PPROM. The authors were hoping that the women who received progesterone shots would make it to the 34 weeks pregnant goal or until the baby's lungs had matured. Unfortunately, as they tallied the results while the trial was still ongoing, they saw no difference in the two groups. Only 3% of the progesterone group made it to a favorable gestational age while 8% of the placebo group made it to a favorable gestational age. Perhaps the progesterone at least lengthened the amount of time from when the women joined the study to when the delivered? Unfortunately, no. This, too, was no different between the two groups. There was also no difference in poor outcomes for the infant, which included stillbirth or death, difficulty breathing, bleeding in the brain, a bowel disorder called "necrotizing enterocolitis," or systemic infection. Other maternal complications, like infection of the uterus or needing a c-section, were also no different in the two groups.

Because the results showed the authors their intervention was making no difference, they actually stopped the trial earlier than planned. Unfortunately, for women with PPROM, progesterone shots have not proven to be the miracle cure we are all hoping for.