Louisiana lawmakers have passed a bill to the governor’s desk requiring doctors prescribing abortion pills to inform women of the option to seek reversal of the procedure. The pills may be prescribed up to 9 weeks of gestation. The Democrat governor opposes abortion and regularly signs anti-abortion legislation.

The law would require a doctor prescribing the two pill process to provide a written statement to the woman: “If after immediately taking the first pill you regret your decision, please consult a physician or healthcare provider immediately to determine if there are options available to help you in continuing your pregnancy.”

The American Pregnancy Association states that a woman must act as soon as possible and receive large doses of progesterone (which promotes gestation, as the name implies) starting within 24-48 hours of taking the first pill (mifepristone, or RU-486) to block the effects of the pill. Some abortion reversals have occurred as long as 72 hours after taking the first pill.

Legislatures in Arkansas, Idaho, South Dakota, and Utah have passed similar legal requirements in recent years.

The American College of Obstetrics and Gynecology points out there have been no scientific (strictly speaking, randomized, blinded, and placebo controlled) clinical studies to determine timing or the proper dose of progesterone or the efficacy of attempted reversal. One can easily appreciate the ethical issues, among other things, and see why such a study is not likely to be funded, if anyone were even interested to conduct such research.

However, a group of physicians reported an observational case series of 547 attempted reversals in an article in Issues in Law & Medicine in 2018. Women received different doses of progesterone by different techniques within 72 hours of taking the first pill. Those who took high oral doses had 68% success. Those taking injections (a variable number from 1 to 11) had an average of 64% success.

However, success was also mitigated by gestational age. Those at 5 weeks (who took mifepristone within a few days of being late for their menstrual cycle and then immediately sought reversal) only had 25% success (combing data from delays up to 72 hours and all techniques of taking progesterone). If the woman takes the mifepristone pill only and does nothing, the pregnancy persists about 25% of the time. Thus, there was no clear benefit to taking progesterone in the 5 week group, although those promptly starting progesterone by injection or by high oral doses had greater success.

There was 46% success at 6 weeks, 49% at 7 weeks, 61% at 8 weeks and 77% success at 9 weeks. It is felt like success rates would have been higher if progesterone was started within 24-48 hours of taking the first pill and if the most successful techniques had been used by all. There were no adverse reactions in mother’s and no birth defects in babies.

So, a woman who takes the first abortion pill and changes her mind about wanting an abortion within 24-48 hours and then receives progesterone either by a series of injections or by high oral doses has a good chance of saving the pregnancy. Since about 40% of abortions in the US are now by these pills (and about 60% in Europe), women should receive proper notification of their options.