The fertile window

A pregnancy theme runs through this week's BMJ—from the optimum interpregnancy interval for minimising maternal morbidity and mortality (p 1255) to diagnosing ectopic pregnancy (p 1235). Wilcox and colleagues also offer a fresh perspective on the definition of the fertile window (p 1259). Conventional wisdom speaks of six fertile days in an average woman's menstrual cycle, five days before ovulation and the day of ovulation itself, but Wilcox finds that the fertile window is much wider than was thought and stretches between days 6 and 21. This is good and bad news, not least for the rhythm method (www.sexhealth.org/infocenter/GuideSS/rhythm.htm).

However, most people resorting to the web will want advice on fertility rather than contraception, and they won't be disappointed. The Couple to Couple League talks about a complex cycle involving phases, days, and thermal shifts (www.ccli.org/nfp/index.shtml) until you realise it doesn't make any sense. But why bother trying to understand when Deb Donovan can guide you through the complexities of body basal temperature, cervical positioning, and secretions (www.parentsplace.com/fertility/conception/gen/0,3375,11181-2,00.html)? In fact there are groups and gizmos wherever you turn. Tom Weschler's Taking Charge of Your Fertility is clearly the most fashionable book in fertility circles (www.amazon.com/exec/obidos/ASIN/0060950536/ivillagepp/105-1837617-0535915). Carol Petherbridge, a naturopathic physician, and Marilyn Lerner, a midwife, offer you Woman's Window, a microscope-like device that equates fertile days with peculiarities in salivary patterns (www.greensprings.com/moon/).

More believably, the World Health Organization estimates that more than 300 million people worldwide are not satisfied with contraceptive methods, resulting in 8-30 million unintended pregnancies each year (www.who.int/rht/fpp/fpp_challenges.htm). What the Holy See makes of all this is unclear: the Vatican's website has a long way to go before it picks up the beat of the internet's rhythm (www.vatican.va/).