Progesterone protects infants against preterm birth: BMJ

Preterm birth is the most important problem in obstetric care and globally the most important cause of neonatal mortality, morbidity, and subsequent neurodevelopmental disorders. Progesterone is widely understood to reduce preterm birth in pregnant women with a short cervical length. A second potential preventive treatment is the use of a cervical pessary, which was reported to reduce preterm birth at less than 34 weeks in women with a singleton baby and a cervical length of less than 25 mm.

The Amsterdam UMC research team studied the optimal treatment for pregnant women with a cervical length shorter than 25 mm at the 20-week ultrasound. Eligible participants had a healthy singleton pregnancy and a cervical length of 35 mm or less between 18 and 22 weeks gestation. Those assigned to the pessary group received an Arabin25 cervical pessary, removed at 36 weeks. Participants in the progesterone group self-administered 200 mg vaginal progesterone capsules daily until 36 weeks. Data collection included maternal and obstetric history, pregnancy details, and neonatal outcomes, with follow-up until 10 weeks after the due date.

The results revealed that in women who had singleton births with no prior spontaneous preterm birth of less than 34 weeks’ gestation and with a mid-trimester cervical length of 35 mm or less, pessary did not improve perinatal outcome compared with progesterone. In the subgroup of a cervical length of 25 mm or less, differences seemed larger in favour of progesterone, especially for extremely preterm birth at less than 28 weeks.

"This is an important improvement that can contribute to the reduction of preterm births and the associated complications, such as an increased risk of infant mortality and long-term health problems for the child," said Eva Pajkrt, professor of obstetrics at Amsterdam UMC. "Based on our study, we recommend measuring the length of the cervix of all pregnant women during the 20-week ultrasound. Women with a cervix shorter than 25 mm should be informed about the possibility of treatment with Progesterone."

Reference: Charlotte E van Dijk, Annabelle L van Gils, Maud D van Zijl, Bouchra Koullali, Eline S van den Akker, Brenda J Hermsen, Wilhelmina M van Baal, Henricus Visser, Yolanda M de Mooij, Martijn A Oudijk, Ben WJ Mol, Brenda M Kazemier, Eva Pajkrt; Journal: The BMJ; DOI: 10.1136/bmj-2023-077033