In one study of oral contraceptive pills, women with a body mass index (BMI) in the overweight range (a BMI of 25 or more) had a higher risk of pregnancy than those in the normal weight range.

有一项针对口服避孕药片开展的研究发现，体重指数(BMI)达到超重范围(BM I值等于或大于25)的女性比体重指数正常的女性更容易怀孕。

youdao

About one million packs of the pills, which are high dose contraceptive pills, are sold in Britain a year.

BBC: News | UK Politics | MPs call for over-the-counter pills

It said that other studies had found oestrogen to cause thrombosis and strokes, in the same way as older-style contraceptive pills.

BBC: Lab mice

While oral contraceptives have a good safety record (and Barr Laboratories' trial of 1, 400 women showed no evidence that Seasonale is riskier than conventional contraceptive pills, except for a higher incidence of irregular bleeding in the first few months of use), Dr Hitchcock is keen to see women exercise caution when it comes to prolonged use of anything containing sex hormones.

ECONOMIST: Controlling menstruation