Is chemical birth control causing miscarriages of already-conceived children? What about breaking your uterus for good? Let’s review the three ways chemical birth control works (OB/GYN Donna Harrison goes into greater detail here).
1) Preventing an egg from being released. Early versions of the Pill were higher in estradiol, which made this mechanism—preventing ovulation—the primary mode of action. However, well-documented links of estradiol to cardiovascular risks such as stroke and heart attack led the pharmaceutical industry to “improve” upon the product by reducing estradiol dosing in products, which led to a greater dependency on the progestin component of the product instead. That means, using today’s products, more eggs are jailbreaking out of the ovary. So those other mechanisms matter more.
2) Slowing down the sperm that bust through the front door to fertilize the egg. This happens by thickening the cervical mucus, which would otherwise be a watery welcome mat during the fertile phase of a woman’s cycle.
These are the methods that we usually think of when we think about chemical birth control like the Pill: it prevents conception, right? However, there is a third mechanism, right there in the labels for most of these products.
The Lighter the Dose, the More Likely It Causes Miscarriage
3) Preventing a fertilized egg (i.e. after conception) from hunkering down in the wall of the uterus, where it can grow normally. Progestin in birth control thins the endometrial lining (uterine wall), but a fertilized egg needs a thick, fluffy, blood-rich uterine wall to attach to and begin growth. Without it, the embryo can’t survive, and a miscarriage occurs. Remember, the lower the dose you’re taking (and doctors naturally prefer to put a woman on the lowest dose that still achieves the desired effect), the more this third “back-up plan” is engaged.
Some pro-life, pro-birth control advocates have disputed this mechanism (even though the mechanism is listed, again, right there in all the Food and Drug Administration labels for the products). But then why does the entire in vitro fertilization (IVF) industry rely on hormonal stimulation of a thick endometrium prior to embryo transfer? Many IVF doctors won’t even bother transferring an embryo in a patient if her endometrium doesn’t get to a certain thickness. That’s how undisputed the link is between implantation/pregnancy success and endometrial thickness in a context outside of the birth-control conversation.
Long-Term Chemical Usage Reduces Your Ability to Have a Baby
Maybe you’re okay with risking a miscarriage of an already-conceived embryo. What about breaking your uterus for good?
Let’s say your life stage changes and you’re ready to try to have a baby. You go off the Pill or the intrauterine device or whatever you’re taking. It takes a few months for the effects of the birth control to wear off and then you’re good to go, right?
Wrong. A ground-breaking 2012 study of infertile women trying to conceive using IVF showed that those who had been on the Pill for a long time (five years) had five times the odds of not having a uterine lining thick enough to sustain pregnancy when compared to women who had been on the Pill less than five years. The effect was similar for longer use (10 years or more, about 4.5 times the odds). Not surprisingly, the women with the too-thin lining had half the success rate in getting pregnant during the IVF process as women with thicker lining, even under hormonal stimulation to thicken it up.
Ladies, did your doctor tell you all the facts before writing that prescription? Did she tell you that the “safer,” lower-dose products could potentially lead to miscarriages of already-conceived embryos? Did she tell you that the longer you stay on the Pill, the more likely you are to ruin your uterus for baby-hosting altogether? Is this the freedom and peace of mind you were seeking when you popped that first Pill? Just asking.