A reader writes:
Please take a moment to merge your miscarriage series with the religious corporations thread, because science: Plan B does not cause abortion because it does not prevent implantation. Plan B is progesterone. It does absolutely nothing if you have already ovulated and had the misfortune of having conceived the night before. In fact, as every woman who has had trouble staying pregnant knows, progesterone is what they prescribe, after a few miscarriages, to help a fertilized egg implant and “stick” in the uterus. So it actually HELPS pregnancies become more viable.
But if you already conceived, you are screwed; Plan B actually ups the chances that you will end up with a baby. Plan B only works if you had sex and have not yet ovulated, in which case the hormone surge will push your ovulation a couple weeks into the future, preventing you from releasing that egg down into the fallopian pool of waiting sperm. It in no way whatsoever interrupts an actual pregnancy after the moment of conception. It does not harm a single hair on a blastocyst’s one-celled head.
Indeed, an overwhelming number of studies in the past decade back up the reader’s point that Plan B does not prevent implantation. Last year the NYT did an extensive investigation that showed how all the ambiguity around the issue is traced to the FDA’s dubious labeling of Plan B back in 1999:
Labels inside every box of morning-after pills, drugs widely used to prevent pregnancy after sex, say they may work by blocking fertilized eggs from implanting in a woman’s uterus. Respected medical authorities, including the National Institutes of Health and the Mayo Clinic, have said the same thing on their Web sites. … But an examination by The New York Times has found that the federally approved labels and medical Web sites do not reflect what the science shows. Studies have not established that emergency contraceptive pills prevent fertilized eggs from implanting in the womb, leading scientists say. Rather, the pills delay ovulation, the release of eggs from ovaries that occurs before eggs are fertilized, and some pills also thicken cervical mucus so sperm have trouble swimming.
It turns out that the politically charged debate over morning-after pills and abortion, a divisive issue in this election year, is probably rooted in outdated or incorrect scientific guesses about how the pills work.
Because they block creation of fertilized eggs, they would not meet abortion opponents’ definition of abortion-inducing drugs. In contrast, RU-486, a medication prescribed for terminating pregnancies, destroys implanted embryos.
The notion that morning-after pills prevent eggs from implanting stems from the Food and Drug Administration’s decision during the drug-approval process to mention that possibility on the label — despite lack of scientific proof, scientists say, and objections by the manufacturer of Plan B, the pill on the market the longest. Leading scientists say studies since then provide strong evidence that Plan B does not prevent implantation, and no proof that a newer type of pill, Ella, does. Some abortion opponents said they remain unconvinced.
After The Times asked about this issue, A.D.A.M., the firm that writes medical entries for the National Institutes of Health Web site, deleted passages suggesting emergency contraceptives could disrupt implantation. The Times, which uses A.D.A.M.’s content on its health Web page, updated its site. The medical editor in chief of the Web site for the Mayo Clinic, Dr. Roger W. Harms, said “we are champing at the bit” to revise the entry if the Food and Drug Administration changes labels or other agencies make official pronouncements. “These medications are there to prevent or delay ovulation,” said Dr. Petra M. Casey, an obstetrician-gynecologist at Mayo. “They don’t act after fertilization.”
The F.D.A. declined to discuss decisions about the effect on implantation or to say whether it would consider revising labels. But Erica Jefferson, an F.D.A. spokeswoman, acknowledged: “The emerging data on Plan B suggest that it does not inhibit implantation. Less is known about Ella. However, some data suggest it also does not inhibit implantation.”
Scientists say the pills work up to five days after sex, primarily stalling an egg’s release until sperm can no longer fertilize it. Although many people think sperm and egg unite immediately after sex, sperm need time to position themselves. … Some abortion opponents said that while emergency contraceptives’ primary function may be delaying ovulation, they doubted that scientists could exclude the possibility of implantation effects. “I would be relieved if it doesn’t have this effect,” said Richard Doerflinger, associate director of the Secretariat of Pro-Life Activities for the United States Conference of Catholic Bishops. “So far what I see is an unresolved debate and some studies on both sides,” he said, adding that because of difficulties in ethically testing the drugs on women, “it’s not only unresolved, but it may be unresolvable.”
Several scientists acknowledged that absolute proof may be elusive; in science, as James Trussell, a longtime emergency contraception researcher at Princeton, said, “You can never prove the negative.” But he and others said the evidence from multiple studies was persuasive.
How did the statement about implantation end up on F.D.A.-approved labels? Beginning with the 1999 approval process, the maker of Plan B — Barr Pharmaceuticals, later acquired by Teva Pharmaceuticals — asked the F.D.A. in writing not to list an implantation effect on the label, said people familiar with the requests who asked for anonymity because such discussions are considered confidential. Anti-abortion activists were not yet publicly focusing on the issue. “There were other drugs that I remember causing controversy,” said Dr. Jane E. Henney, the F.D.A. commissioner then. “This wasn’t one.”
Back then, scientific research concentrated on whether Plan B’s active ingredient, a synthetic progesterone, safely and effectively prevented pregnancy, not on how it worked, said Dr. Kristina Gemzell-Danielsson, an obstetrics and gynecology professor at the Karolinska Institute in Sweden, who participated in World Health Organization studies leading to F.D.A. approval. The F.D.A.’s own description was speculative, saying Plan B “could theoretically prevent pregnancy by interfering with a number of physiological processes” followed by a long list, including ovulation and implantation.
A New York Times review of hundreds of pages of approval process documents found no discussion of evidence supporting implantation effects.