Risk of endometriosis, adenomyosis, and related symptoms among female offspring according to conception by assisted reproductive technologies.

OBJECTIVE

To study the relationship between conception by assisted reproductive technology (ART) and risk of endometriosis/adenomyosis in female offspring.

DESIGN

National registry-based cohort study.

SUBJECTS: We studied 449,611 female offspring born in Norway between 1991 and 2006 who were still alive and residing in Norway when they were 15 years of age using a national registry linkage.

EXPOSURE: Conception by ART.

MAIN OUTCOME MEASURES: The risk of endometriosis/adenomyosis and related symptoms (menstrual pains, pain during intercourse, and heavy menstrual bleedings) in female offspring conceived by ART compared with those not conceived by ART was studied using a Cox regression, adjusting for maternal characteristics, including age, parity, history of endometriosis/adenomyosis, and country of birth.

RESULTS

Female offspring conceived by ART had a higher risk of endometriosis/adenomyosis than those not conceived by ART (adjusted hazard ratio [HR], 1.49; 95% confidence interval [CI], 1.14-1.94). We also observed an increased risk of seeking healthcare for menstrual pains (adjusted HR, 1.11; 95% CI, 1.02-1.21), pains during intercourse (adjusted HR, 1.36; 95% CI, 1.12-1.65), and heavy menstrual bleedings (adjusted HR, 1.31; 95% CI, 1.14-1.51) among female offspring conceived by ART. When we compared offspring not themselves conceived by ART to mothers with a history of using ART and offspring not conceived by ART to mothers with no history of use of ART, we observed no difference in the risk of endometriosis/adenomyosis or related symptoms.

CONCLUSION

Female offspring conceived by ART have an increased risk of endometriosis/adenomyosis and related symptoms. Additional studies are needed to replicate our findings and to further explore potential underlying mechanisms.