London, England, Mar 1, 2007 / 12:05 pm (CNA).- German scientists are now confirming what many Catholic couples have known for some time – the natural family planning method known as STM works.  Scientists have been taken aback by a new study which found STM to be as effective, if not more so, than the contraceptive pill in family planning.

For years married Catholics have used the natural family planning method known as the symptom-thermal method (STM) as a morally licit means to maintain the sexual part of their conjugal relationship while at the same time decreasing the chances of having additional children due to “physical, economic, psychological, or social conditions.”  The Catholic Church teaches that natural family methods can be used in a moral manner if the couple remains open to the blessing of children – something which the Church sees as essential to the vocation of marriage.

The new study brings light to the scientific effectiveness of STM, while ignoring its moral uses.

The symptom-thermal method enables couples to identify accurately the time of the woman's fertile phase by measuring two indicators — her temperature and observing cervical secretions. In the largest prospective study of STM, researchers found that if couples either abstained from sex, as required in STM, or used a barrier (condom, etc) method during the fertile period, the rate of unplanned pregnancies per year was 0.4 percent and 0.6 percent respectively.

The research was published in Europe's leading reproductive medicine journal Human Reproduction.

Out 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 an artificial contraceptive method to be rated as “highly efficient,” there should be less than one pregnancy per 100 women per year when the method is used correctly, explained Petra Frank-Herrmann, managing director of the natural fertility department at the University of Heidelberg, Germany.

The results of this research, conducted by the German Natural Family Planning Study Centre between 1985 and 2005, indicates one pregnancy occurred per 250 women per year for STM users.

“Therefore, we maintain that the effectiveness of STM is comparable to the effectiveness of modern contraceptive methods such as oral contraceptives, and is an effective and acceptable method of family planning," said the researcher.

There are other benefits to STM. Toni Belfield of the Family Planning Association in England says STM puts contraception under a woman’s control. "It's easy to learn, it can enhance a relationship, and it's easy to stop if a woman decides she does want to become pregnant," she told The Guardian.

Rebecca practices the method with her husband, Geoff. They switched to STM after her intrauterine device (IUD) left her in constant pain and bleeding.

"I loved the fact that STM didn't require hormones, or putting anything unnatural in my body," she told The Guardian. It was also painless, she added, and made her more aware of her fertility cycle.

“What it does is teach you exactly what's going on with your body. I know my body and that's very liberating for a woman," another STM user added.

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