Multiple pregnancy and birth: Twins, triplets and high-order multiples. Overview

Multiple gestations are high risk pregnancies which may be complicated by prematurity,low birthweight, pre-eclampsia, anaemia, postpartum haemorrhage, intrauterine growth restriction, neonatal morbidity and high neonatal and infant mortality. There are more multiple births today in part because more women are receiving infertility treatment, which carries a risk of multiple pregnancy.They are many risk factors for multiple pregnancy such as: race, heredity, maternal age and pregnancy history as well as fertility drugs and assisted reproductive technology(ART). The frequency of twins increases with maternal age and number of pregnancies. Multiple pregnancy is more common in women who utilize fertility medications to undergo ovulation induction or superovulation. Assisted reproductive technology (ART) procedures such as in vitro fertilization (IVF) also contribute to the increase in the multiple birth rate. The risk of multiple pregnancy increases as the number of embryos transferred increases.