ORIGINAL ARTICLE Reproductive epidemiology Reproductive prognosis in daughters of womenwith andwithout endometriosis

study question: Do daughters of women with endometriosis exhibit an increased risk of endometriosis and impaired long-term repro-ductive prognosis when compared with daughters of women without endometriosis? summaryanswer:Daughters ofwomenwith endometriosis haveover a 2-fold higher riskof endometriosis but nodifference in long-term reproductive prognosis compared with controls. what is known already: Several studies have found an increased prevalence of endometriosis in sisters andmothers of womenwith endometriosis, but none have examined the long-term reproductive prognosis in daughters of these patients. study design, size, duration: A controlled historical cohort study with a 33-year follow-up. participants/materials, setting, methods: Among women 15–49 years old during the period 1977–1982, 24 691 were diagnosedwith endometriosis during the study period. Thesewomenwere agematched to 98 764womenwithout endometriosis. Daughters of these two groups were followed until 31 December 2009 for an endometriosis diagnosis and reproductive outcomes. Women were excluded from the study at death or if they emigrated. main results and the role of chance: Except for 4–6 % of emigrated women, the follow-up rate of the study was almost 100%. Daughters of women with endometriosis (n 12 389) had a 2.12-fold (95 % confidence interval 1.89–2.37, P, 0.0001) increased risk of being diagnosed with endometriosis, compared with daughters of women without endometriosis (n 52 371). Delivery rate, risk of spontaneous abortions and ectopic pregnancies were similar for the two cohorts, whereas induced abortions were slightly more frequen