[Multiple pregnancies: epidemiology and management].

Since the 1980s, the percentage of multiple pregnancies in the Netherlands has increased. Nowadays, the percentage of triplets is decreasing but there is still an increase in the percentage of twin pregnancies. A major cause is that Dutch women tend to delay starting a family until an advanced age. This increases their chances of a spontaneous multiple pregnancy. Moreover, they are prone to subfertility and consequently have a greater chance of undergoing treatments involving assisted-reproduction techniques such as intra-uterine insemination (IUI) and in-vitro fertilisation. In the Netherlands, the majority of higher order multiple pregnancies result from mild ovarian hyperstimulation in combination with IUI. In case of in-vitro fertilisation, since the practice of transferring a maximum of two embryos still results in 20-25% twin pregnancies, single-embryo transfer should be advocated more often.