Hum. Reprod. Advance Access originally published online on May 16, 2008
Human Reproduction 2008 23(8):1941-1948; doi:10.1093/humrep/den169
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Perinatal outcomes of twin births conceived using assisted reproduction technology: a population-based study
1 National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, 1600 Clifton Road, MS-E86, Atlanta, GA 30333, USA 2 Massachusetts Department of Health, Boston, MA, USA 3 Northeastern University, Boston, MA, USA 4 Division of Reproductive Health, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, Atlanta, GA, USA
5 Correspondence address. Tel: +1-404-498-3558; Fax: +1-404-498-3550; E-mail: sboulet{at}cdc.gov, sbul{at}cdc.gov
BACKGROUND: Approximately 18% of multiple births in the USA result from assisted reproduction technology (ART). Although many studies comparing ART and naturally conceived twins report no difference in risks for perinatal outcomes, others report slight to moderate positive or protective associations.
METHODS: We selected twin deliveries with and without indication of ART from Massachusetts live birth–infant death records from 1997 to 2000 linked to the US ART surveillance system. The sample was restricted to deliveries by mothers with increased socioeconomic status, private health insurance and intermediate/plus prenatal care use. Our final sample included 1446 and 2729 ART and non-ART twin deliveries, respectively. Odds ratios (OR) for associations between ART and perinatal outcomes were adjusted for maternal demographic factors, smoking, prenatal care and hospital care level.
RESULTS: ART twin deliveries were less likely than non-ART to be very preterm (adjusted OR 0.75; 95% confidence interval 0.58–0.97) or include a very low birthweight (<1500 g) infant (0.75; 0.58–0.95) or infant death (0.55; 0.35–0.88). In stratified analyses, these findings were observed among primiparous deliveries, but there were no risk differences among multiparous ART and non-ART twin deliveries.
CONCLUSIONS: ART treatment was not a risk factor for adverse perinatal outcome, and risks for several outcomes were somewhat lower among ART twin deliveries. Nonetheless, ART is strongly associated with twinning and twins remain a high-risk group, relative to singletons. Promoting singleton gestation in assisted conception is an important strategy for reducing adverse outcomes.
Key words: assisted reproduction technology/infant/low birthweight/premature birth
The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention. Submitted on January 30, 2008; resubmitted on March 31, 2008; accepted on April 8, 2008.