Pregnancies and births resulting from in vitro fertilization: French national registry, analysis of data 1986 to 1990. FIVNAT (French In Vitro National)

To describe the characteristics of pregnancies and children at birth resulting from IVF-ET and to assess whether they differ from those after natural conception.

Prospective multicenter survey.

A national registry, representing 80% of all French IVF-ET activity for the period 1986 to 1990.

Data on 7,024 pregnancies, 5,371 deliveries, and 6,879 newborn infants.

A form is completed for every clinical pregnancy.

Spontaneous abortion, ectopic pregnancy, multiple pregnancy, prematurity, hypotrophy, perinatal and neonatal mortality, and congenital malformations rates.

The spontaneous abortion and ectopic pregnancy rates were, respectively, 17.6% and 5.8%. More than a quarter (26.8%) of the deliveries were multiple births. The preterm birth rate (29.3%), the low birth weight rate (36.2%), and the perinatal and neonatal mortality rates were higher than the national average. The rate of malformations (2.8%) was comparable with the general population (2.1%).

Assisted conception frequently results in multiple pregnancy, and this is the main determinant of pregnancy outcome. Nevertheless, it is not the only risk factor for prematurity, which is also more frequent among IVF singleton newborn. The prevalence of congenital malformations is not higher than after natural conception.