Vaginal progesterone 400 mg v.s 200 mg for prevention of preterm labor in twin pregnancies: a randomised controlled trial

Abstract

Parturition is preceded by complex materno-fetal interactions which are not fully understood despite research involving studies of both humans and animals. Now, well-established that hormones like estrogen, progesterone, corticotrophin releasing hormone, cortisol and oxytocin play a vital role in maintaining uterine quiescence throughout pregnancy and in triggering the cascade of events that leads to labor and cervical ripening. The risk of preterm birth before 37week is 8-9 fold higher in twins than in singleton pregnancies. Multiple pregnancies result in neonatal mortality 5-6 times more than singletons. Preterm birth is the biggest issue contributing to this. Compared to singletons, surviving twins show a higher risk of hypothermia, seizures, respiratory distress, re-hospitalization, motor and cognitive problems in childhood. In preterm birth predictive tests, different cut off values of cervical length is used for singletons and twins, possibly reflecting differing pathophysiological mechanisms causing the onset of spontaneous PTB. Several studies now have shown that progesterone supplementation during the second and third trimester of pregnancy reduces the risk of preterm birth in female with a singleton pregnancy and a short cervical length or a history of a previous preterm delivery.