Early initiation of anti-androgen treatment is associated with increased probability of spontaneous conception leading to childbirth in women with polycystic ovary syndrome: a population-based multiregistry cohort study in Sweden

Abstract

Abstract STUDY QUESTION Is anti-androgen treatment during adolescence associated with an improved probability of spontaneous conception leading to childbirth in women with polycystic ovary syndrome (PCOS)? SUMMARY ANSWER Early initiation of anti-androgen treatment is associated with an increased probability of childbirth after spontaneous conception among women with PCOS. WHAT IS KNOWN ALREADY PCOS is the most common endocrinopathy affecting women of reproductive age. Hyperandrogenism and menstrual irregularities associated with PCOS typically emerge in early adolescence. Previous work indicates that diagnosis at an earlier age (<25 years) is associated with higher fecundity compared to a later diagnosis. STUDY DESIGN, SIZE, DURATION This population-based study utilized five linked Swedish national registries. A total of 15 106 women with PCOS and 73 786 control women were included. Women were followed from when they turned 18 years of age until the end of 2015, leading to a maximum follow-up of 10 years. First childbirth after spontaneous conception was the main outcome, as identified from the Medical Birth Registry. PARTICIPANTS/MATERIALS, SETTING, METHODS Participants included all women born between 1987 and 1996 with a diagnosis of PCOS in the Swedish Patient Registry and randomly selected non-PCOS controls (ratio 1:5). Information on anti-androgenic treatment was retrieved from the Swedish Prescribed Drug Registry with the use of Anatomic Therapeutic Chemical (ATC) codes. Women with PCOS who were not treated with any anti-androgenic medication were regarded as normo-androgenic, while those treated were regarded as hyperandrogenic. Women were further classified as being mildly hyperandrogenic if they received anti-androgenic combined oral contraceptive (aaCOC) monotherapy, or severely hyperandrogenic if they received other anti-androgens with or without aaCOCs. Early and late users comprised women with PCOS who started anti-androgenic treatment initiated either during adolescence (≤ 18 years of age) or after adolescence (>18 years), respectively. The probability of first childbirth after spontaneous conception was analyzed with the use of Kaplan–Meier hazard curve. The fecundity rate (FR) and 95% confidence interval for the time to first childbirth that were conceived spontaneously were calculated using Cox proportional hazards regression models, with adjustment for obesity, birth year, country of birth and education level. MAIN RESULTS AND THE ROLE OF CHANCE The probability of childbirth after spontaneous conception in the PCOS group compared to non-PCOS controls was 11% lower among normo-androgenic (adjusted FR 0.68 (95% CI 0.64–0.72)), and 40% lower among hyperandrogenic women with PCOS (adjusted FR 0.53 (95% CI 0.50–0.57)). FR was lowest among severely hyperandrogenic women with PCOS compared to normo-androgenic women with PCOS (adjusted FR 0.60 (95% CI 0.52–0.69)), followed by mildly hyperandrogenic women with PCOS (adjusted FR 0.84 (95% CI 0.77–0.93)). Compared to early anti-androgenic treatment users, late users exhibited a lower probability of childbirth after spontaneous conception (adjusted FR 0.79 (95% CI 0.68–0.92)). LIMITATIONS, REASONS FOR CAUTION We lacked direct information on the intention to conceive and the androgenic biochemical status of the PCOS participants, applying instead the use of anti-androgenic medications as a proxy of hyperandrogenism. The duration of anti-androgenic treatment utilized is not known, only the age at prescription. Results are not adjusted for BMI, but for obesity diagnosis. The period of follow-up (10 years) was restricted by the need to include only those women for whom data were available on the dispensing of medications during adolescence (born between 1987 and 1996). Women with PCOS who did not seek medical assistance might have been incorrectly classified as not having the disease. Such misclassification would lead to an underestimation of the true association between PCOS and outcomes. WIDER IMPLICATIONS OF THE FINDINGS Early initiation of anti-androgen treatment is associated with better spontaneous fertility rate. These findings support the need for future interventional randomized prospective studies investigating critical windows of anti-androgen treatment. STUDY FUNDING/COMPETING INTEREST(S) This study was funded by the Health Research Council of New Zealand (18-671), the Swedish Society of Medicine and the Uppsala University Hospital. Evangelia Elenis has, over the past year, received lecture fee from Gedeon Richter outside the submitted work. Inger Sundström Poromaa has, over the past 3 years, received compensation as a consultant and lecturer for Bayer Schering Pharma, MSD, Gedeon Richter, Peptonics and Lundbeck A/S. The other authors declare no competing interests. TRIAL REGISTRATION NUMBER N/A