Comparison of the pregnancy outcomes of subfertile women after infertility treatment and in naturally conceived pregnancies.

Adverse obstetric outcomes in pregnancies achieved through assisted reproductive technology (ART) could either be due to the technology or to the underlying subfertility or to both. To address this issue, we compared the pregnancy outcomes of singletons conceived naturally after a long time to pregnancy (TTP) with those of ART pregnancies. We analysed an existing birth database. Altogether 428 ART pregnancies were compared with 928 spontaneously conceived pregnancies with TTP of 2 years or more, during the period 1989-2007 at Kuopio University Hospital, Finland. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated for pregnancy outcomes. Between treated and untreated subfertile women no significant differences were found in the rates of Caesarean sections (OR 1.21, 95% CI 0.89-1.64), preterm births (OR 1.28, 95% CI 0.81-2.03), small for gestational age (SGA) birthweight (OR 0.95, 95% CI 0.65-1.39), need of neonatal intensive care (OR 1.28, 95% CI 0.88-1.88) or low Apgar scores (OR 1.19, 95% CI 0.47-3.04). However, compared with pregnancies of women with TTP 0-6 months, ART pregnancies had significantly increased risks of preterm or very preterm birth, low birthweight and need of neonatal intensive care. The risks of preterm birth, SGA, need for neonatal intensive care and low Apgar scores were not significantly different between subfertile women who conceived spontaneously and those who conceived through ART indicating that maternal factors relating to subfertility and not only infertility treatment are associated with adverse pregnancy outcomes.