An increasingly popular hormonal “treatment” for pregnant women with a history of preterm birth does not work, a major new international study shows.
A total of 789 women from 39 Australian, New Zealand, and Canadian maternity hospitals took part in the PROGRESS study, led by Professor Caroline Crowther at the University of Auckland-based Liggins Institute. Half were randomised to give themselves progesterone pessaries for 14 weeks starting at mid-pregnancy; the other half used the matching placebos.
Researchers then assessed the health of the babies and their mothers. The rate of health problems in the babies, including respiratory distress syndrome, where the baby struggles to breathe, was not significantly different between the two treatment groups. The mother’s health and side effects of treatment were also overwhelmingly similar.
Progesterone pessaries are sometimes prescribed to pregnant women who have previously given birth before 37 weeks, who have more than double the risk of another preterm birth. Based on earlier evidence, it was thought that the treatment could delay birth, reducing the risk and severity of complications affecting babies born too early, and improve mothers’ health.