[Prevention of twin pregnancy after IVF/ICSI using embryo transfer].

One of the negative aspects of in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) is the increased risk of multiple pregnancies. Multiples of high order (triplets and pregnancies of higher order) are obsolete to both doctors and patients and need to be avoided. However, there is an epidemic of twin pregnancies with a higher risk of obstetric, perinatal and neonatal complications than singleton pregnancies and with an important psychosocial, economic and financial impact for the parents to be. A reduction in the number of twins can only be obtained by transfer of one embryo. If this guideline would be applied to all cycles, a dramatic fall in pregnancy rate would occur. In a selected patient group one selected embryo with an excellent implantation potential can be transferred.