OBJECTIVE To investigate the prevalence of hypertensive disorders of pregnancy (HDP), and the roles of polycystic ovary syndrome (PCOS), obesity, weight gain (WG) and hyperandrogenaemia in the development of HDP by age 46. DESIGN prospective population-based cohort. Setting and population The Northern Finland Birth Cohort 1966 (NFBC1966) METHODS Follow-up at ages 14, 31 and 46, including women with (n=408) and without (n=3373) HDP. HDP was combined from the questionnaire data at age 46, hospital discharge records and Finnish Medical Birth Registers. Women with both oligo-amenorrhea and hirsutism at age 31 and/or with PCOS diagnosis by age 46 (self-reported PCOS, srPCOS, n=279) were compared with women without symptoms or PCOS diagnosis (n=1577). Main outcome measures Association of PCOS and WG through life with HDP RESULTS Women with srPCOS had an increased HDP risk ([OR]=1.56 [95%CI:1.03-2.37]), but the association disappeared after BMI adjusting at age 31. Increase of BMI from age 14 to 31 was significantly greater in srPCOS (median [interquartile range]:5.94kg/m2[3.69;11.1], p<0.001) and non-PCOS (4.89kg/m2[3.21;7.57], p<0.001) women with HDP and in srPCOS women without HDP (4.59kg/m2[2.40;7.54], p=0.009) compared to non-PCOS without HDP. Among women with srPCOS, BMI increase was greater in women with than without HDP (5.94kg/m2 [3.69;11.1] vs 4.59kg/m2[2.40;7.54], p=0.015). Hyperandrogenaemia at 31 or 46 did not associate with HDP (OR=1.44[95%CI: 0.98-2.11]). CONCLUSION Obesity and weight gain from adolescence to age 46, but not srPCOS or hyperandrogenaemia, were associated with an increased risk of HDP.