Severalreproductive factors have been constantly related with possibility forendometriosis, signifying that hormonal variation may have a significant influenceon the risk of developing endometriosis.
For Example,early age at menarche 10, 11, 12, 13, 14 and short menstrual cycle length 13,14are correlated with an increased chance, while parity 13 and current oralcontraceptives 15 use are associated with a decreased risk. Circulatingestradiol and estrone, which stimulate ectopic and eutopic endometrial tissue,are higher among women at an earlier age of menarche and in nulliparous women 16-20. Though not a reproductive riskfactor, a consistent inverse association has also been observed between bodymass index (BMI) and endometriosis 10, 11–12, 14, 58, 59 and may also relate to hormonaldifferences between heavy and lean women. Unfortunately, the evaluation oftubal ligation, parity, and oral contraceptive use in relation to endometriosisrisk has been plagued by methodologic issues. Tubal ligation has beenhypothesized to decrease endometriosis risk through blocking retrogrademenstruation from reaching the pelvic cavity.
However, the association betweentubal ligation and endometriosis is difficult to interpret since endometriosisis characterized by infertility, and women who seek a tubal ligation are morelikely to be parous than the general population 21, 22. The mean age at diagnosis is 25–29years, but it is often greater in women who present with infertility ratherthan pelvic pain. 23 Although the mechanism is unknown,circulating estrogens are known tobe lower in women who smoke 37 and could inhibit the growth and persistence of endometriotictissue. The association between alcoholand caffeine consumption is similarlymixed and may depend on fertility status.
Among infertile women, severalstudies have reported increased risk with higher alcohol or caffeine intake 54, 55. The association between physical activity andendometriosis is unclear 33, higher intake of long-chain omega-3 fatty acids has beenassociated with reduced endometriosis risk 44.