Natural regulation of fertility.

Natural methods play an important part in the overall control of world fertility. Lactational amenorrhoea makes a very large contribution to fertility control in developing countries and recent advances in our understanding of the biology of lactation and fertility have enabled guidelines to be prepared to help nursing mothers who wish to use the natural contraceptive effect of breastfeeding to space their families. Methods to identify more reliably the fertile phase of the menstrual cycle, possibly using home monitoring of hormone levels in the urine, would greatly increase the applicability of NFP methods. If used effectively, natural family planning can have a high effectiveness rate but all methods are extremely unforgiving of risk-taking in the fertile phase. More research is required to identify those factors which could serve to improve the efficacy of NFP methods.