It used to be rare for multiple pregnancies to occur but we have seen a spectacular rise in them in France between 1970 and 1986. Triplet deliveries increased threefold. The authors analyse a personal series of 23 pregnancies (19 triplets, 3 quadruplets and 1 quintuplet pregnancy). Sixteen of these 23 were medically induced. The main complications that have been observed were: threatened premature delivery in 86%, high blood pressure in 34.7%, anaemia in 50%, and urinary tract infections in 30.4%, 6.8% of the babies had congenital malformations. Reviewing the literature has made it possible to discern the epidemiological factors causing multi-fetal pregnancies: family history, high female fertility, maternal age, ethnic factors, hormonal contraception etc... At present it is medically assisted reproduction that is the big supplier of multi-fetal pregnancies in developed countries. We have reviews of several maternal as well as fetal complications: the ovarian hyperstimulation syndrome, extra-uterine pregnancy, hypertension, anaemia, spontaneous abortion, prematurity, intra-uterine growth retardation and malformations.