Prospective European multi-center study of natural family planning (1989-1992): interim results. The European Natural Family Planning Study Groups

Since 1989 an international multicenter prospective study to evaluate the effectiveness and acceptability of natural family planning (NFP) methods in Europe has been conducted by the NFP Research Center at the University of Düsseldorf in collaboration with the European Zone of the International Federation for Family Life Promotion (IFFLP). Fourteen NFP-organizations from nine European countries participate in the study. Cycle data from women in the fertile age group are transferred to a special standard computer sheet by the respective organizations and forwarded at three-monthly intervals to the study center for analyses. To date, 10,045 cycles from 900 women aged between 19 and 54 years have been analyzed. This paper presents the pregnancy rate for the women aged between 19 and 45 years of age, who contributed 9284 cycles. In the analyses the cycles were subdivided into two categories consequent to sexual practices during the fertile phase: group I (NFP only--4277 cycles) use only NFP to avoid a pregnancy; group II (FA/mix--5007 cycles) where barrier methods or coitus interruptus during the fertile phase, at least in some cycles, were used to avoid a pregnancy. The women used different clinical indicators such as basal body temperature (BBT), cervical mucus, calculations, cyclical cervical changes or combinations of these to determine the beginning and the end of the fertile phase necessitating a further division into four subgroups, A, B, C, D, and different efficiency rates for each of these groups. In group A (symptothermal method, double check) 15 unintended pregnancies (UIP) occurred in 7404 cycles, giving a pregnancy rate of 2.4 Pearl Index (PI); in group B (muco-thermal method) there were 12 UIP in 1352 cycles with a pregnancy rate of 10.6 (PI); in group C (mucus to detect the beginning and mucus and BBT to determine the end of the fertile phase) there was one UIP in 434 cycles, and in group D (mucus method only) there was one IUP in 70 cycles. The numbers in group C and D are too small to calculate a pregnancy rate (PI). No pregnancy was observed in women over 40 years of age. Our conclusion from these preliminary results is that in the continent of Europe, the symptothermal method when used with periodic abstinence (NFP only = group I) and fertility awareness with the use of barriers during the fertile phase (FA/mix = group II) are effective methods of family planning.(ABSTRACT TRUNCATED AT 400 WORDS)