Does the Pill Cause Abortion?

During a radio show, William Cutrer, M.D., and I discussed our book, The Contraception Guidebook. The interviewer quoted a source who said women taking the pill, which is supposed to prevent ovulation, have “breakthrough ovulation” about 50 percent of the time. I found another source on the web (after looking for fewer than two minutes) that put the number closer to 30 to 40 percent. Not surprisingly, the sources quoted in the research were old.

Before I go further, let me say I’m not a big fan of the pill. What I am a fan of is fairness in reporting. Truth. Honestly. That sort of thing.

So here goes.

Back when I was an infertility patient, we could tell how many babies I had the potential to conceive in a given cycle while taking fertility drugs. We knew this by means of a mid-cycle ultrasound. Every menstrual month around day 14, I’d go to the doctor’s office and I’d have a sonogram so we could take a look at the activity going on in my abdomen. If we saw two fluid-filled cysts, that meant two ova were maturing (there was one microscopic “egg” maturing in each). If we saw three, that meant possible triplets. If we saw four or more, hubby and I abstained. Just in case.

In a normal menstrual cycle, if a woman were to have a vaginal ultrasound, she and the operator would likely see one cyst. And they would assume there was a single egg maturing inside.

Here’s what gets interesting with the pill. Although sonograms confirm that women taking oral contraceptive pills sometimes do have such fluid-filled cysts present, that doesn’t necessarily mean an egg is inside nor does it mean that if it is, it gets released. Consider these findings:

. In 1996, twenty-four healthy female volunteers ages 20–34 with normal ovulatory cycles were included in a study to investigate the effect on inhibition of ovulation of an oral contraceptive. No escape ovulation was observed.

. In 1997, one hundred eighteen women at ten German centers participated in a study that measured the impact of two low-dose oral contraceptives and their ability to stop ovarian activity. No patients ovulated in any treatment cycle.

. In 2002, one hundred women were randomly assigned to receive varying oral contraceptives over a single treatment cycle. Breakthrough ovulation was observed in three subjects in one group. Only one of these escape ovulations was considered the result of treatment failure (the patients either forgot their pills or they took medications that reversed the pills’ effects).

. In a 2002 study, one hundred thirty women took oral contraceptives beginning on the third day. That’s three days later than recommended. And sure enough, these women had significantly more ovarian follicular development than women who take the pill as prescribed. Yet the postponement did not appear to increase actual ovulation rates.

Conclusion: The presence of follicles does not necessarily equal ovulation. Recent research demonstrates that breakthrough ovulation is a relatively rare event.