In vitro fertilization (IVF) in Sweden: infant outcome after different IVF fertilization methods.

OBJECTIVE: To compare infant outcome after different IVF techniques.
DESIGN: A register study in Sweden of IVF infants compared with all infants born.
SETTING: National health registers. PATIENT(S): We studied 16,280 IVF infants, 30% of whom were conceived by intracytoplasmic sperm injection (ICSI). INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Multiple births, infant sex, preterm birth, low birth weight, and small for gestational age among singletons, mortality, low Apgar score, neonatal diagnoses. RESULT(S): Twinning was less frequent after frozen standard IVF (18.1%) and after ICSI (21.8%) than after fresh standard IVF (24.4%). The male/female ratio was significantly increased in infants conceived after standard IVF. No significant differences were seen between singleton infants conceived after different IVF methods with respect to preterm birth, low birth weight, or infant mortality, with the possible exception of frozen standard IVF, for which some of these rates were lower than after fresh standard IVF. Infants born after ICSI had an indicated lower risk of respiratory problems than infants born after standard IVF. CONCLUSION(S): Little difference in outcome was seen after different IVF methods. The differences observed might be due to dissimilar characteristics of the treated women (e.g., because ICSI was mainly used in connection with male infertility).