Trends and correlates of good perinatal outcomes among singleton infants conceived through ART in the US, 2000-2005

Abstract

OBJECTIVE: During 2000-2005, 271,270 assisted reproductive technology (ART) births occurred in the U.S.; of these 132,533 (48.9%) were singleton births. We analyzed data to evaluate trends in and correlates of the delivery of a term, normal birthweight singleton infant after ART.DESIGN: Retrospective analysis of National ART Surveillance System (NASS) data.MATERIALS AND METHODS: The outcome was defined as the delivery of a term (>37 weeks gestation), normal birthweight infant (> 2,500 grams). Data on all singleton infants born after ART during 2000-2005 and reported in NASS were assessed for trends using chi-square tests. Data from 2005 were examined for bivariate associations, and adjusted odds ratios (AOR) and 95% confidence intervals (95%CI) were computed using multiple logistic regression. Covariates included demographic characteristics, fertility history, infertility diagnosis, type of ART treatment, number of embryos transferred, and number of fetal hearts detected during pregnancy.RESULTS: From 2000 to 2005, the percentage of singleton ART births with a good outcome decreased from 83.6% to 82.9% (p=0.004). The odds of a good outcome were higher for women with one prior birth (AOR 1.25, 95%CI1.09-1.43), women whose reason for ART was male factor infertility (AOR 1.18, 95%CI1.08-1.28), and women who used their own fresh embryos rather than patient or donor thawed embryos (AOR 1.13, 95%CI1.03-1.23). The strongest effect was for the detection of 1 versus >1 fetal heart (AOR 1.79, 95%1.61-1.99).CONCLUSION: Birth history, certain fertility diagnoses, and embryo type affect pregnancy outcomes among ART singletons. Results indicate that singleton births resulting from singleton pregnancies do substantially better. Enhanced promotion of single embryo transfer would decrease the risk of adverse outcomes among ART singletons. OBJECTIVE: During 2000-2005, 271,270 assisted reproductive technology (ART) births occurred in the U.S.; of these 132,533 (48.9%) were singleton births. We analyzed data to evaluate trends in and correlates of the delivery of a term, normal birthweight singleton infant after ART. DESIGN: Retrospective analysis of National ART Surveillance System (NASS) data. MATERIALS AND METHODS: The outcome was defined as the delivery of a term (>37 weeks gestation), normal birthweight infant (> 2,500 grams). Data on all singleton infants born after ART during 2000-2005 and reported in NASS were assessed for trends using chi-square tests. Data from 2005 were examined for bivariate associations, and adjusted odds ratios (AOR) and 95% confidence intervals (95%CI) were computed using multiple logistic regression. Covariates included demographic characteristics, fertility history, infertility diagnosis, type of ART treatment, number of embryos transferred, and number of fetal hearts detected during pregnancy. RESULTS: From 2000 to 2005, the percentage of singleton ART births with a good outcome decreased from 83.6% to 82.9% (p=0.004). The odds of a good outcome were higher for women with one prior birth (AOR 1.25, 95%CI1.09-1.43), women whose reason for ART was male factor infertility (AOR 1.18, 95%CI1.08-1.28), and women who used their own fresh embryos rather than patient or donor thawed embryos (AOR 1.13, 95%CI1.03-1.23). The strongest effect was for the detection of 1 versus >1 fetal heart (AOR 1.79, 95%1.61-1.99). CONCLUSION: Birth history, certain fertility diagnoses, and embryo type affect pregnancy outcomes among ART singletons. Results indicate that singleton births resulting from singleton pregnancies do substantially better. Enhanced promotion of single embryo transfer would decrease the risk of adverse outcomes among ART singletons.