Fertility treatment tied to birth defects, but unclear as to whether technology or biology is to blame
MONDAY, May 7 (HealthDay News) -- Treatment with assistive reproductive technology is associated with an increased risk of birth defects, but it is not clear whether this risk is due to the infertility treatments or the underlying biology preventing conception, according to a study published online May 5 in the New England Journal of Medicine to coincide with presentation at the annual clinical meeting of the American College of Obstetricians and Gynecologists, held from May 5 to 9 in San Diego.
To investigate the extent to which birth defects after infertility treatment may be due to underlying parental factors, Michael J. Davies, M.P.H., Ph.D., from the University of Adelaide in Australia, and colleagues linked a census of treatment with assisted reproductive technology with registries of births and terminations and registries of birth defects.
The researchers identified 308,974 births, of which 6,163 resulted from assisted conception. Compared with pregnancies not involving assisted conception, for pregnancies involving assisted conception there was an increased rate of any birth defect (unadjusted odds ratio [OR], 1.47; multivariate adjusted OR, 1.28). For in vitro fertilization, the unadjusted OR for birth defects was 1.26 (95 percent confidence interval [CI], 1.07 to 1.48) and the multivariate-adjusted OR was 1.07 (95 percent CI, 0.90 to 1.26). For intracytoplasmic sperm injection, the unadjusted OR was 1.77 and the multivariate-adjusted OR was 1.57. A history of infertility was significantly associated with birth defects, regardless of assistance with pregnancy.
"The increased risk of birth defects associated with IVF was no longer significant after adjustment for parental factors," the authors write. "The risk of birth defects associated with ICSI remained increased after multivariate adjustment, although the possibility of residual confounding cannot be excluded."