Indirect evidence of the occurrence of ovulation, which is generally accepted, is an increase in plasma or serum progesterone. Pelvic ultrasonography can estimate the probable time of ovulation within 12 h. There is a close association between the rise in progesterone, luteinizing hormone (LH) and oestrogen peaks and ovulation. A WHO study reported that ovulation occurred at a median time of 8 h after the rise in plasma progesterone, 15 h after the LH peak and 24 h after the oestrogen peak. The basal body temperature (BBT) method is the most effective in determining the premenstrual infertile period, but it is unreliable for an accurate determination of ovulation and the postmenstrual infertile period. Nor is BBT an effective method of predicting ovulation during postpartum lactational amenorrhoea. Therefore, BBT is usually used as a secondary indicator of ovulation and is combined with more reliable indicators. Observed changes in cervical mucus patterns can be used to define the probable fertile period, although this method produces a wide range of days. The peak mucus symptom is closely correlated with ovulation. Mucus symptoms can be used as a guide for the timing of blood or urine samples for estimation of LH, oestrogen and progesterone or their metabolites. Symptothermal methods incorporate other symptoms such as cervical changes, intermenstrual pain, breast tenderness and backaches, but these are secondary signs of ovulation and are recommended to be used in conjunction with mucus and BBT.
The efficacy of fertility awareness based (FAB) methods of family planning is critically reviewed. The objective was to investigate the efficacy and the acceptability of the symptothermal method (STM), an FAB method that uses two indicators of fertility, temperature and cervical secretions observation. This paper will recommend a more suitable approach to measure the efficacy. Since 1985, an ongoing prospective observational longitudinal cohort study has been conducted in Germany. Women are asked to submit their menstrual cycle charts that record daily basal body temperature, cervical secretion observations and sexual behaviour. A cohort of 900 women contributed 17,638 cycles that met the inclusion criteria for the effectiveness study. The overall rates of unintended pregnancies and dropout rates have been estimated with survival curves according to the Kaplan-Meier method. In order to estimate the true method effectiveness, the pregnancy rates have been calculated in relation to sexual behaviour using the 'perfect/imperfect-use' model of Trussell and Grummer-Strawn. After 13 cycles, 1.8 per 100 women of the cohort experienced an unintended pregnancy; 9.2 per 100 women dropped out because of dissatisfaction with the method; the pregnancy rate was 0.6 per 100 women and per 13 cycles when there was no unprotected intercourse in the fertile time. The STM is a highly effective family planning method, provided the appropriate guidelines are consistently adhered to.
The objective of the present paper is to review the main results of recent European cycle databases on ovulation detection and determination of the fertile window performed by the women themselves. The ongoing German Long-term Cycle Database currently comprises 32788 prospectively collected cycle charts of 1551 women, the I European Cycle Database (10 countries) 1328 women/19048 cycles, the II European Cycle Database (six countries) 782 women/6724 cycles, and the World Health Organization Database (one European country) 234 women/2808 cycles. The women record cycle parameters (cervical mucus changes, temperature rise, etc.), family planning intention and sexual behavior. With the symptothermal method of natural family planning it has become possible to determine the fertile window in order to avoid pregnancy with a method effectiveness of 0.3%. According to a small sub-study, the ovulation time observed by the women themselves correlates closely with ovulation detected by ultrasound and measurement of luteinizing hormone (correlation within 1 day in 89% of the 62 cycles). Fertility awareness methods can be integrated into the management of sub-fertility. They seem to shorten the time to pregnancy. Self-observation of the fertile window puts women into a position to develop a high level of reproductive competence that could be used much more in different areas than is currently the case.
Fertility AwarenessSymptothermal MethodBillings Ovulation MethodNFP vs Contraceptive Methods
The scientific foundations and most notable features of modern natural family planning (NFP) methods are described. NFP techniques require observation of the signs and symptoms occurring during the fertile and infertile phases of the menstrual cycle. Abstinence during the fertile period is implied when NFP is used to avoid pregnancy. Modern NFP methods are associated with success rates similar to those of oral contraceptives, the IUD, and condoms. NFP methods are based on such phenomena as the limited survival time of the ovum and sperm, the occurrence of ovulation only once per cycle, the ability to diagnose ovulation using simple means, and the ability of human beings to delay sexual satisfaction. Among the advantages of NFP methods are low cost, brevity of the required training time, increased knowledge of the body and capacity for self control, shared responsibility by both partners, and moral and religious acceptability. The Billings and symptothermal methods have shown average use-effectiveness rates ranging from 71.5 to 89.5% and from 83.4 to 97.8%, respectively. All studies of symptothermal methods conducted since 1985 have shown Pearl indexes under 5. The symptothermal method is based on observation of the duration of previous cycles, cervical mucus, basal body temperature, and optionally on palpation of the cervix and other symptoms such as breast swelling, acne, intermenstrual bleeding, and mood changes. Use of the symptothermal method requires special graph paper for recording the temperature and other symptoms. The beginning of the fertile phase is recognized by subtracting 19 from the shortest cycle in the past year, or by the appearance of cervical changes or changes in the mucus.
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 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)