How contraceptives work

YOU WOULD think, given the certainty of their positions that those against the reproductive health bill would like to bring it to a vote as soon as possible. After all, if, as they assert, the bill is opposed by a majority of Filipinos who are Catholics and would not win the support of a majority of the people’s representatives, then they should want nothing more than to bring the proceedings to a quick conclusion.

But why is it that the anti-RH people keep seeking to delay a vote on the floor of the House of Representatives, and a debate before the full Senate? In the House, more than 30 anti-RH legislators have signified their intent to debate with Albay Rep. Edcel Lagman, the RH bill’s main sponsor. And judging from the performance of those who have already interpellated Lagman, the issues brought up are old hat, if not entirely fallacious. And when the debate begins to score points for the RH side, count on an anti-RH lawmaker to bring up the issue of a quorum, thereby forcing the closing of a session.

In the Senate, both Senate President Juan Ponce Enrile and Sen. Tito Sotto want to postpone floor debates on the bill to give way to a Senate investigation on whether some forms of contraceptives are “abortifacient,” that is, they work by terminating a viable pregnancy or by preventing the implantation of a fertilized ovum. Induced abortion, after all, is illegal under Philippine law.

Such an investigation could conceivably delay progress on the RH bill, maybe well after the Aquino administration. So much hinges on the definition of “abortion,” on the question of the “viability” of a pregnancy as well as the definition of life. And as we well know, medical doctors, ethicists, theologians, philosophers and ordinary people have been debating “when life begins” for well over a millennium with no end in sight.

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WELL, let me help facilitate matters.

At last year’s Women Deliver Philippines conference, one of the speakers was Dr. Mario Festin, an obstetrician-gynecologist and professor at the UP College of Medicine who is now based in Geneva with the main office of the World Health Organization.

Festin shared with participants updates on current contraceptive technology and the latest findings of the WHO on the “mechanisms of action” of different methods of contraception. He also included effectiveness rates of the various methods and the latest developments in the field.

Before we get to the most important parts of Festin’s presentation, a brief backgrounder. Contraceptives fall under two broad categories: temporary, that is, one can stop using them and still get pregnant; or permanent, that is, the method provides lifetime protection although fertility can be restored but only with much difficulty and expense.

The permanent surgical methods of contraception are tubal ligation and vasectomy.

Under the temporary methods, we have barrier methods, like spermicides and condoms that essentially prevent the meeting of egg and sperm; hormonals, including pills, injectables and IUDs with hormonal content; so-called “natural” methods like fertility awareness (and avoidance), coitus interruptus or withdrawal, and LAM, which takes advantage of the natural protection accorded by full and exclusive breastfeeding during the first six months after the birth of a child. The last are “mechanical” methods like the “copper T” IUD.

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SINCE the methods proposed for investigation are mainly hormonals and the IUD, let’s discuss them first.

Oral contraceptive pills fall under two categories: combined estrogen and progestin pills and progestin-only, said Festin. “Combined” pills work by preventing ovulation, that is, preventing the release of eggs from the ovaries, and have the added benefit of providing protection from endometrial and ovarian cancers. Progestin-only pills, injectables and implants work mainly by “thickening the cervical mucus to prevent sperm and egg from meeting” and also by preventing ovulation. Another advantage cited by Festin is that progestin-only contraceptives can be used by a woman even while she is breastfeeding.

The main mechanism of action of a “copper T” IUD, according to WHO studies, is to “induce a local inflammatory reaction” in the uterine cavity, enhanced by the “release of copper ions into the luminal fluids of the genital tract, which is toxic to sperm.” Thus, added Dr. Festin, “very few sperms reach the fallopian tube and those that do have poor fertilizing activity.”

While IUDs also cause changes in the endometrium or lining of the uterus, “there is no direct evidence that suggests that these changes lead to preventing implantation of a fertilized ovum,” said Festin.

Let me add that IUDs are, next to permanent methods, the cheapest form of contraception since they provide up to 10 years’ protection under proper use, and can replace the pill for older women.

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FESTIN cannot stress enough “the need for evidence-based guidance,” so that a woman or couple may base their family planning practices on the best available evidence; address misconceptions regarding who can safely use contraception; reduce unnecessary medical barriers to contraception; and improve access and quality of care in family planning.

Let’s hope, too, that should the Senate investigation push through, as Enrile and Sotto threaten, that what we will witness is “evidence-based investigation” in aid of legislation, and not testimonies and conclusions based on personal assumptions and bogus scientific assertions. Those who wish to learn more about the WHO guidelines and findings may access the WHO website or request for printed copies of its various materials.