1. There are two main types of "pills": the combined oral contraceptive pill (COCP) and the progestin only pill (POP). COCPs have the hormones estrogen and progestin whereas POPs have only progestin.
2. COCPs and POPs also come in different forms. Generally oral. But they can also be delivered via other methods such as intramuscular injection.
3. The COCP has a 0.5/100 women years (WY) failure rate. That is, if 100 women used the COCP for a year, then 0.5 of them would get pregnant. Whereas the POP has between a 0.3 to 5/100 WY failure rate.
4. Of course, the pill could fail in women with certain conditions or diseases. For example, if a woman has problems in her gastrointestinal system absorbing the pill. If she vomits or has diarrhea. If she's taking other drugs which could interfere with the effects of the pill. But these women should be advised if they visit a doctor. But by far the most common reason for failure is user error i.e. the woman didn't take the pill as indicated.
5. There are three main ways contraceptive pills prevent, well, contraception:
a. Prevention of ovulation.
b. Production of cervical mucus.
c. Development of a hostile endometrium.
As far as I'm aware, no one really takes issue with the first two. After all, if there's no ovulation, then there's no egg for the sperm to fertilize in the first place.
As for the second, cervical mucus is mucus in the woman's cervix. Contraceptive pills would cause cervical mucus to become more viscous so that sperm can't easily enter further into a woman's body to fertilize an egg. So that's fine too.
But many people take issue with the third one. When people say the pill causes the development of a hostile endometrium, what they mean is this development of a hostile endometrium occurs because there's a constant (rather than cyclical) level of progestin (progesterone). A constant level stops the endometrium from becoming secretory which in turn results in an atrophic endometrium. The endometrium is thinner, there are less blood vessels feeding into it so as to support an embryo, etc. So it's significantly harder for an embryo to attach itself to this "hostile" endometrium.
6. I think Steve had a good response to the "remote" objection. I'd add in order for an embryo to fail to attach to an atrophic endometrium, it means the first two must've failed. But the first two are highly unlikely to fail if a woman takes the pill as indicated. Still there is a "remote" chance it could happen. But if a healthy adult woman takes the pill as indicated, either COCP or POP, then at least all the numbers I've seen seem to indicate prevention of ovulation occurs at rates in the high 90th percentiles. Of course, not every woman is "healthy." Much more could be said here.
7. Also, there's apparently some debate over whether the pill actually causes a hostile endometrium or not. For example, here is some info from a Christian medical doctor hosted on a Christian pro-life website which actually argues that the hostile endometrium theory isn't necessarily valid and so taking the pill could possibly be permissible:
[T]he third proposed method of action, the so-called “hostile endometrium theory”, has little direct evidence to support it. Drug manufacturers have heralded it from the beginning without proof, and it has been echoed by two generations of investigators without verification. There is indirect evidence that the OC [oral contraceptive] produces a thinner, less glandular, less vascular lining, and there is direct evidence from the field of in vitro fertilization that a thinner, less glandular, less vascular lining is less likely to allow the attachment of the new human being when it enters the uterus. However, when a woman taking OCs does ovulate, the corpus luteum (the ovarian follicle turns into the corpus luteum after ovulation) produces ten to twenty times the levels of both estrogen and progesterone seen in a non-non-ovulatory pill cycle. This results in the growth of stroma, blood vessels, glands, and glandular secretions to help prepare the lining for implantation. If there is no conception after ovulation, the corpus luteum ceases to function about two weeks after ovulation and menses follows. However, if conception occurs following ovulation, the embryo releases the human chorionic gonadotropin hormone (HCG), which stimulates the corpus luteum to continue its function until the placenta takes over hormone production two months later.8. That said, I don't know how recent the research is on which the Christian doctor is basing his comments. Personally, I'd like to take some time to look into the most up to date research about the pill causing a hostile endometrium (if there is any). Perhaps start with PubMed. It could be that recent research does indeed prove the hostile endometrium theory valid, which would mean this aspect of the pill could be an abortifacient. If so, then it could be ethically problematic for Christians. But at least from what I can tell at the moment it seems debatable. Hopefully others more knowledgeable will weigh in.
The proponents of the “hostile endometrium theory” argue that OCs are abortifacient based upon the third mechanism of action. The medical literature clearly supports the claim that the uterus becomes thinner and less glandular as a result of the OCs, however, the medical literature comes to this conclusion from non-ovulatory pill cycles. It is assumed that this finding in non-ovulatory pill cycles would prevent implantation of the embryo conceived in an ovulatory pill cycle, but this presumption is false. If a woman on OCs ovulates and conceives, everything changes: through the HCG’s affect on the corpus luteum, and the corpus luteum’s release of high levels of estrogen and progesterone, the uterus is able to nourish its new guest very well.
It is noteworthy that in a normal menstrual cycle, on the day of ovulation, the endometrium is not receptive to implantation. If the embryo were to drop down through the fallopian tubes into the uterus on that day, it could rightly be called a “hostile endometrium”. But following ovulation, the corpus luteum transforms this hostile endometrium into a receptive, nourishing bed, where the embryo will attach about one week later after its trip through the fallopian tube, and where the baby will continue to develop until birth.
9. BTW, here's an image of the relevant female reproductive anatomy:
I haven't read it, but a friend recommends a book titled Does the Birth Control Pill Cause Abortions? by Randy Alcorn. It's currently $1.99 for the Kindle.
ReplyDeleteAlso, God, Marriage, and Family (2nd ed.) by Andreas Kostenberger and David Jones has a helpful section on the topic starting on p 126.