Reproductive System & Sexual Disorders: Current Research
Open Access

Abstract

Birth Defects after Assisted Reproductive Technology in Japan: Comparison between Multiples and Singletons, 2004-2009

Syuichi Ooki

More than 2% of all infants in Japan are born after ART (Assisted Reproductive Technology) and this percentage is rapidly increasing. The relationship between ART and birth defects according to plurality is seldom examined. Japanese complete nationwide data of ART from 2004-2009 presented by the Japan Society of Obstetrics and Gynecology, which include information on birth defects, were used for analyses. There were a total of 177,548 pregnancies after ART. The Relative Risk (RR) and 95% Confidence interval (CI) for birth defect categories according to the International Classification of Disease, 10th edition (ICD-10) were calculated with singletons as the reference group. In multiples compared to singletons, the percentage of pregnancies with any birth defects per 10,000 pregnancies was significantly higher (RR=1.68, 95% CI 1.47-1.93), the percentage of birth defects per live births was not significantly higher (RR=0.92, 95% CI 0.80-1.06). The number of birth defects in the same fetus/neonate was significantly greater in multiples compared to singletons (p<0.05). The most common birth defects of major classification were congenital malformations of the circulatory system for both singletons and multiples. RRs per pregnancy were significant for seven out of the 11 main categories. RRs per pregnancy were significant for congenital malformations of the nervous system (RR=3.58, 95% CI 2.49-5.14), other congenital malformations (RR=2.45, 95% CI 1.38-4.34), congenital malformations of genital organs (RR=2.25, 95% CI 1.19-4.24), congenital malformations of the circulatory system (RR=2.22, 95% CI 1.81-2.73), cleft lip and cleft palate (RR=2.01, 95% CI 1.20-3.35), congenital malformations of the eye, ear, face and neck (RR=1.74, 95% CI 1.02-2.98), and congenital malformations and deformations of the musculoskeletal system (RR=1.42, 95% CI 1.00-2.01). Some subcategories or individual diseases were more common in multiples compared to singletons. RRs of any birth defects per pregnancy and live births both decreased when patent ductus arteriosus was excluded.