Because All Pills are Not Equal, Here's a Quick Birth Control Primer

All pills are not equal.

Feb 13 2012, 5:45pm

It seems like every day there’s a new pundit-fueled controversy surrounding women’s healthcare and reproductive rights. Planned Parenthood is under threat of defunding and people, are fighting about it. Obama’s healthcare plan includes birth control coverage for women, and people are fighting about it. Now, Catholics are fighting over whether Catholic institutions have to provide women with birth control coverage under company health insurance. Catholics believe that life begins at the instant of conception. As soon as the sperm hits the egg, that’s a person, so they oppose many forms of birth control and all abortions.

With all the rhetoric and grandstanding and the politicizing of women’s healthcare, it’s easy to forget that, at its core, this issue is exactly that; it’s about healthcare and medications for women. All these contraceptive methods we see thrown around in the news, how do they actually work? It’s important to understand the science behind any medication, and it’s especially important to educate ourselves about such a divisive issue. So, I’ve broken down two common forms of oral contraception and one form of abortion, explaining how they work and how they’re different. All pills are not equal.

Hormonal Birth Control Pills

The most commonly used form of contraception in the US is the hormonal birth control pill, commonly referred to as ‘the pill.” Birth control pills are usually made up of two synthetic hormones, estrogen and progesterin. This is fairly common knowledge, but how, exactly, do these hormones prevent pregnancy?

Usually, a woman’s hormones cycle throughout the month; a spike in estrogen causes ovulation, but taking synthetic hormones stabilizes a woman’s estrogen levels, so there’s no fluctuation and no ovulation. Specifically, estrogen prevents the pituitary gland from producing follicle stimulating hormone (FSH) and luteinizing hormone (LH).

You know how people say women are born with “all the eggs they’ll ever have”? Well, that’s right, but only sort of. If you’re a lady, you possess the maximum number of primordial oocytes (the precursors to your eggs) 20 weeks after conception. From this point, the number of primordial oocytes drastically falls. Later, these primordial oocytes will become primary oocytes (primary eggs). But even these don’t all become actual, fertilizable eggs.

This graph shows the number of primordial oocytes a woman has throughout her lifespan.

Basically, if you’re not taking hormonal birth control, each month 12-20 primary follicles will begin to develop into secondary follicles due to elevated levels of FSH; one will become a mature ovum. Ovulation is an extremely exceptional fate for a primordial oocyte; the vast, vast majority will be cast off at some point in a female’s gestation or lifetime. Finally, LH triggers the release of that mature egg into the fallopian tube (ovulation).

Progestin works in several different ways. First, it inhibits the production of LH, thus inhibiting ovulation. It also thickens cervical mucus, creating a wall of defense against sperm. There is also speculation that it makes a woman’s uterine lining inhospitable to implantation, though this has never been shown in medical research. So, even if an egg is fertilized, it might have a hard time implanting into the uterine wall and resulting in a pregnancy.

Emergency Contraception

Emergency Contraception (EC) has been the subject of its own firestorm of controversy. Should it or should it not be available without a prescription? Should it be available to women under 18? Should it be stocked in the aisles or behind the pharmacist’s counter? The most commonly known EC is Levonorgestrel, often known by the brand name Plan B. Despite all the anti-choice rhetoric and its constant misrepresentation in the media, it’s not an abortion pill. I don’t know how many more times we can say it: Not an abortion. Never going to give you one. Ever.

Plan B basically works by preventing ovulation, but it does it quickly. Since sperm can survive in the body for 3-5 days, if you have unprotected sex before you ovulate they can lay in wait for a few days and then pounce on an egg when it’s released. Plan B might also inhibit the implantation of a fertilized egg, but it won’t ever cause an implanted egg to un-implant. At that point, you’re just pregnant.

Medical Abortion

This is the abortion pill. It’s a medication called mifepristone. You may have also heard it called RU-486, which is what it was called when it was being developed. If a woman is less than 63 days pregnant and wants to terminate her pregnancy, she can take the abortion pill instead of opting for a surgical abortion. During a medical abortion a woman will take two pills, mifepristone and then, 1-3 days later, misoprostol.

Mifepristone works by blocking the hormone progesterone. Without progesterone, the uterine lining breaks down and a pregnancy can’t continue. Misoprostol causes a woman’s uterus to contract, much like what happens when a woman has her period or experiences a miscarriage.

Follow Kelly Bourdet on Twitter: @kellybourdet