Feb 24, 2007
Natural Family Planning
Could the contraceptive pill be replaced by a “natural” approach to family planning? It could if a study by Petra Frank-Herrmann of the Department of Gynaecological Endocrinology at the University of Heidelberg, Germany, proves reproducible (pardon the pun).
She and her colleagues have demonstrated that using two indicators for the fertile period in a woman’s menstrual cycle and avoiding unprotected sex during that time is just as effective as the contraceptive pill for avoiding unplanned pregnancies. The study was published in Human Reproduction this week.
The symptothermal method (STM) uses temperature and cervical secretion to pinpoint a woman’s fertile time. The German team carried out the largest prospective study of the method yet and found that if couples abstained from unprotected sex during this time the rate of unplanned pregnancies per year was 0.4% and 0.6% respectively. Out of all the 900 women who took part in the study, including those who had unprotected sex during their fertile period, 1.8 per 100 became unintentionally pregnant.
“For a contraceptive method to be rated as highly efficient as the hormonal pill, there should be less than one pregnancy per 100 women per year when the method is used correctly,” Frank-Herrman explains, “The pregnancy rate for women who used the STM method correctly in our study was 0.4%, which can be interpreted as one pregnancy occurring per 250 women per year.”
The authors were also surprised by the relatively low rate of unintended pregnancies (7.5%) among women who had unprotected sex during their fertile period. “If people are trying for pregnancy you expect a pregnancy rate of 28% per cycle,” said Frank-Herrmann. “Therefore, we think that some of the couples were practicing conscious, intelligent risk-taking, and were having no unprotected sex during the few highly fertile days, but had unprotected intercourse on the days at the margins of the fertile time when the risk of pregnancy was lower.”
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David Bradley said,
February 23, 2007 at 3:09 pm
STM identifies the beginning and end of a woman’s fertile period based on body temperature and cervical secretions. The first fertile day is when the woman first identifies either: 1) first appearance or change of appearance of cervical secretion, or 2) the sixth day of the cycle. After 12 cycles, this second guideline is replaced by a calculation that subtracts seven days from the earliest day to show a temperature rise in the preceding 12 cycles, in order to identify the first fertile day. The woman is then in her fertile period. The fertile phase ends after the woman has identified: 1) the evening of the third day after the cervical secretion peak day, and 2) the evening when the woman measures the third higher temperature reading, with all three being higher than the previous six readings and the last one being 0.2 degrees C higher than the previous six.
It’s rather complicated and it’s quite a wonder that success rates reported are so high, much easier to pop the pill. But for women and coupled who want to avoid hormonal contraception and are willing to do the science, it seems like an entirely viable method.
DV82XL said,
February 24, 2007 at 9:28 pm
So a way to beat the house in Vatican roulette is it?
Sounds a bit complex for the average couple. Good science if the results hold. However they are extraordinarily good, to the point that I would like to see some verification.
Jim Van Damme said,
March 7, 2007 at 1:26 am
Several peer-reviewed studies on methods of modern NFP have verified the effectiveness. Some go back 20 years. Check out http://nfpsite.aldred.org/effect.html. In fact, some pills lately have had reduced effectiveness because of harmful side effects of higher dosages of artificial hormones.
I’d advise not following Mr. Bradley’s quick summary of the rules below, but reading a book or going to a class. It will become clear how to chart, find fertile times, and the scientific background. BTW there are several types of NFP and many providers. See nfp.freehostia.com for info and resources on all methods.
David Bradley said,
March 7, 2007 at 9:45 am
Jim
I don’t think I was suggesting anyone follow my quick summary of the rules, I was merely reporting on the recent research results on the subject from the Heidelberg team, but thanks for your comment, hopefully your links will provide useful information for visitors with an interest in NFP.