[The Billings method]. / El metodo de Billings.

PIP: The World Health Organization (WHO) has financed a study of the Billings method of family planning in 3 developing and 2 developed countries to obtain objective data on the effectiveness of the method. Although 40% of the 870 couples had previously used another abstinence method and all were highly motivated to use the technique, the life-table pregnancy rate for the year following training in the method reached 20%. 11 studies of the cervical mucus method have been carried out in India, Tonga, Colombia, and Chile and in the US and Australia, often in new programs which did not employ uniform teaching methods. 2 Indian studies showed pregnancy rates of under 6/100 woman years, while 2 studies in developed countries showed rates under 15 and 2 showed rates over 30/100 woman years. Most of the studies have attributed the high pregnancy rates to the failure of couples to observe abstinence. Pregnancy occurred in the 5 countries partcipating in the WHO studies primarily as a result of the failure of couples to abstain from sexual relations during periods identified as fertile, despite active promotion of natural family planning and assistance from instructors at monthly intervals. Other reasons for the high failure rate were late occurrance of mucus flow relative to the time of ovulation, overly early appearance of mucus, and failure to observe or to interpret correctly the mucus symptom. Mucus patterns and facility of interpretation can be affected by various physiological or psychological factors, such as vaginal or cervical infection, vaginal secretion due to sexual stimulation, medicines, tension, and illness. The common observation of higher pregnancy rates among couples who wish to postpone rather than prevent a birth appears to be particularly important in the case of abstinence methods.^ieng