Comparison of perinatal health of children born from IVF in Finland in the early and late 1990s.

The purpose of this study was to investigate whether perinatal health outcomes changed during the 1990s with the increasing use of IVF. Data were from the Finnish Medical Birth Register for periods 1991-1993 and 1998-1999. Outcomes of IVF infants and other infants were compared, both overall and separately for singleton and multiple births, by adjusting for mothers' background variables by logistic regression. The IVF multiple birth rate, especially the number of triplets, declined from the first (1991-1993) to the second (1998-1999) time-period. The outcomes for IVF newborns improved, especially for multiple births. After adjusting for mothers' background variables, the odds ratios for preterm birth and low birthweight decreased among singletons from 2.2 [95% confidence interval (CI) 1.8-2.8] to 1.8 (CI 1.5-2.1) and from 2.4 (CI 1.9-3.1) to 1.7 (CI 1.4-2.1) respectively and more among multiples from 2.4 (CI 2.0-2.9) to 1.5 (CI 1.2-1.7) and from 1.9 (CI 1.6-2.3) to 1.1 (CI 1.0-1.3) respectively. Still, overall the outcomes for IVF infants remained poorer than those for other infants. A correlation was found between increased use of antenatal services and improved outcomes, but causality cannot be assumed. A trend of improved perinatal health of multiple IVF children was found, mainly due to a decrease in higher order multiple births.