Facolta de Medicina e Chirurgia, Universita Degli Studi di Milano, Via Commenda, 12-20122 Milano, Italy. Since the goal of infertility therapy is a healthy child, and multiple gestation puts that goal at risk, multiple pregnancy must be regarded as a serious complication of assisted reproductive treatment cycles. 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. Multiple gestation children may suffer long-term consequences of perinatal complications, including cerebral palsy and learning disabilities. Even when the babies are healthy they must share their parents' attention and may experience slow language development and behavioural problems.
Prevention is the most important means of decreasing multiple gestation rates.
Multiple gestation rates in ovulation induction and superovulation cycles can be reduced by using lower dosage gonadotrophin regimens. If there are more than three mature follicles, the cycle should be converted to an IVF cycle, or it should be cancelled and intercourse should be avoided. In IVF cycles two embryos can be transferred without reducing birth rates in most circumstances. Embryo reduction involves extremely difficult decisions for infertile couples and should be used only as a last resort. Reducing the multiple gestation pregnancy rate should be a high priority for assisted reproductive treatment programmes, despite the pressure from some patients to transfer more embryos in order to improve success.