Multiple Pregnancies

FIVNAT register has collected 10510 deliveries after IVF attempts from 1986 to 1993. The multiple pregnancy rate is 27.2 %, 23.5 % for twin pregnancies, 3.6 % for triplets pregnancies and 0.15 % for multiples pregnancies over 3. Triplet pregnancy proportion, before embryo reduction, reached 8 % in 1989 then decreased to 6.1 % in 1993. In 1994 the proportion of 3 and 4 embryos transfers has decreased and that of 2 embryos transfers has increased, but global pregnancy rate per transfer is 1.6 % lower than pregnancy rate in 1993. This point shows how difficult it is to decrease multiple pregnancy rate without decreasing global pregnancy rate.