Approximately 50% of women aged 18–44 years in the UK use reversible contraception and 50% of these rely on the oral contraceptive pill, 25% use condoms and 12% the intrauterine contraceptive device. About 8% rely on withdrawal (coitus interruptus), the remainder using the diaphragm with or without spermicides or the “safe period” (rhythm method). The effectiveness of all these methods is measured using the Pearl Index — the number of unwanted pregnancies that occur during 100 woman years of exposure (normally fertile women having regular coitus). The natural pregnancy rate (i.e. the Pearl Index without any birth control) is approximately 80. Hormone replacement therapy does not provide adequate contraceptive protection.
KeywordsInfective Endocarditis Ectopic Pregnancy Female Condom Vaginal Ring Clinical Obstetric
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