The rhythm method of contraception is just as effective as the pill, medical professionals stated yesterday.
A better form of the infamously undependable birth control measure is 99.6% effective they disclosed.
However the technique - just having sex when the female's menstrual cycle stops her from becoming pregnant has to be used perfectly.
The "revised" way involves a woman regularly taking her temperature and making other body checks.
Gynaecologist Petra Frank-Hermann observed 200 ladies - and only one in 250 had an pregnancy that wasn't planned each year when it was followed "to the letter."
However she confessed the method takes three months to conquer it correctly - after trying it out herself.
She's quoted as saying in the Sun newspaper:“You need a book to learn or have proper teaching. But it’s like riding a bike — once you’ve learnt it you won’t forget.”
Her findings are printed in the Human Reproduction journal.
Toni Belfield, of the Family Planning Association, commented that it highlights the value of “natural family planning when combining two or more fertility indicators."