Will carrying twins lead to premature birth?

Carrying twins may lead to preterm birth. A twin pregnancy increases the size of the uterus, thereby raising the risk of premature delivery. Before pregnancy, the uterus is about the size of a fist and has a volume of approximately 5 milliliters. In a singleton pregnancy at full term, the baby typically weighs between 6 to 7 kilograms. In a twin pregnancy, each fetus weighs around 5 to 6 kilograms, and combined with the weight of the placenta and amniotic fluid, this causes a significant increase in uterine volume and intrauterine pressure, which may result in preterm labor.