How To Choose A Birth Control Pill

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“The Pill” is not a monolith: there are hundreds of birth control pills out there, and they’re not all the same. But most people are never given a choice. They walk into their local doctor's office, ask for the pill and get a prescription that may or may not be the best one for their particular situation. Given how common this is, it’s no wonder that so many people take a “one size fits all” approach to birth control pills.

Perhaps this is why it seems like the hottest millennial trend of the moment is quitting birth control. While some people are opting for longer-acting methods like IUDs, others seem to be sceptical of hormonal birth control in general and the pill in particular, citing concerns about long-term safety and its effects on mental health.

Everyone is entitled to make their own medical decisions, and going off the pill for any reason certainly counts as such. However, the internet makes it far too easy for people to get all sorts of wrong ideas about complex medical concepts like hormonal contraception. There’s a lot of bad science out there about what the pill actually is, how it works, and the risks it carries — and people are increasingly basing their contraceptive decisions on anecdotes and hearsay rather than sound medical advice.

The science behind the pill in all its different formulations is extremely complicated, but you don’t need a graduate-level reproductive endocrinology class to understand your options — you just need to know that you have options. To help break them down, I spoke with two ob-gyns (obstetrician-gynecologists) who specialise in family planning and contraception: Dr. Anne Davis, Director of the Family Planning Fellowship at Columbia University, U.S.A., and Dr. Kristyn Brandi of Rutgers University, also in the U.S..

A (very) brief history of birth control pills

When we talk about the pill, we’re usually talking about combined oral contraceptives (COCs), which have been around since 1957. In many ways, they’ve barely changed: they still use a combination of progestin and estrogen, which are synthetic versions of the hormones that control the menstrual cycle. When used in combination, these hormones prevent ovulation, thicken cervical mucus, thin the lining of the uterus, and generally trick your body into thinking it’s pregnant.

The very first combination pill, Enovid 10, contained a whopping 10 milligrams of a progestin called noretynodrel, and 0.15 milligrams of an estrogen called mestranol. Both of these medications were at least partially phased out by the mid to late 1960s, but their replacements — norethindrone (progestin) and ethinylestradiol (estrogen) — are widely used to this day. However, modern dosages are much lower: a typical combined pill today might contain 500-1000 micrograms of norethindrone and 20-50 micrograms of ethinylestradiol. That’s between 5 per cent and 10 per cent of Enovid 10’s progestin dose and a third (or less) of its estrogen dose.

Formula selection has also expanded in the last 50 years. These days, you’re not limited to a daily pill: contraceptive patches and rings use the same hormone combinations. Ethinylestradiol is still the go-to estrogen, but today, your progestin options go beyond norethindrone. Scientists have been chasing the perfect progestin for decades, and they’ve synthesised several other options over the years. Progestins are often categorised into “generations” based on how long they’ve been around:

  • First generation: Norethindrone, norethindrone acetate

  • Second generation: Levonorgestrel, norgestrel

  • Third generation: Desogestrel, norgestimate

  • Fourth generation: Drospirenone

Every progestin on the market is both safe and effective at preventing pregnancy, but there are some slight differences. According to Dr. Brandi, first-generation progestins, particularly norethindrone, are very similar to testosterone, while newer progestins hardly resemble it at all. This might influence which side effects you can expect: “Many patients [who] use a first generation progestin... have a lot of what are called androgenic or ‘male-appearing’ side effects: acne, excess hair growth, weight gain, things like that,” she explains. “The newest [progestins] are so far away from testosterone that they actually work as an anti-testosterone, [or] an anti-androgenic medication.”

Dr. Davis cites two other downsides to norethindrone as compared to newer progestins: its short half-life and its relative inability to prevent ovulation. These are most noticeable in pills that contain norethindrone only, with no estrogen at all (sometimes called “mini-pills”): “You have to take [norethindrone-only pills] at basically the same time every day, because the half-life is very short,” she says.

“Also, the bleeding you get is unpredictable, because [norethindrone] is not very good at suppressing ovulation.” However, the estrogen in combined norethindrone pills cancels out these effects enough to be usable for most people.

The key phrase here is “most people.” Dr. Davis emphasises that the slight differences between progestins are practically meaningless for the average user. As long as you take estrogen and some flavour of progestin every day, you are very unlikely to get pregnant, and one pill’s side effects will probably be indistinguishable from another’s. But many people rely on those side effects to treat painful periods and hormonal disorders: “[Certain] pills can specifically target certain side effects,” explains Dr. Brandi. “And if you’re clever about it, you can use [them] to not only prevent you from getting pregnant but also help with other symptoms you may be having.”

What we know about side effects

This brings us to the biggest, thorniest, most controversial aspect of the pill: side effects. In addition to serious conditions like blood clots, birth control pills are frequently blamed for everything from mood swings to weight gain to a general sense of ennui. Some side effects have been studied more than others, so let’s start with the ones we understand best: cancer and blood clots.

On the whole, the pill reduces your cancer risk

There’s widespread concern over the connection between birth control pills and cancer, but it’s mostly unfounded.

While combination pills are associated with an increased risk of breast cancer, this is often cited as a standalone statistic instead of one part of a much larger picture. Oral contraceptives significantly decrease your risk of ovarian, endometrial, and colorectal cancers. They are linked to an increased risk of breast cancer, but that increase is small and doesn’t keep increasing the longer you take pills.

The biggest potential risk increase associated with oral contraceptives is actually for cervical cancer — and according to one study, that risk does increase with continued use. Dr. Davis sums it up nicely: “On balance, birth control pills are preventing a lot more cancer than they would ever cause.”

It’s totally reasonable to worry about cancer when weighing your pill options. Cancer is terrifying and nobody wants it. But cancer isn’t caused by any single factor, and your birth control is unlikely to be the one factor that determines whether or not you get it. With that said, doctors take this stuff pretty seriously — be sure to give yours a complete medical history so they can decide if you’re a good candidate for the pill.

Pregnancy increases your blood clot risk way more than the pill

Increased estrogen levels increase your risk of blood clots, which means that any COC can theoretically do the same. However, modern pill formulas contain such low estrogen doses that the risk is minuscule. As for progestins, they don’t really effect your risk one way or the other. The exception is pills formulated with drospirenone, which carry a roughly threefold risk of blood clots compared to other pills.

If that sounds scary, remember that the absolute risk of blood clots is extremely low, even after that threefold increase — and it still doesn’t come close to the elevated risk during pregnancy and the first 12 weeks postpartum.

With that said, some people do have a higher baseline risk of blood clots than others, particularly smokers over 35. A family history of blood clots also raises your risk, as do certain types of heart disease and being on bedrest. But for the vast majority of people, the pill has a negligible effect on blood clot risk.

Most pills alleviate hormonal acne to some extent

You may have seen some combination pills marketed as being FDA approved to treat acne. But according to Dr. Davis, they all kind of do:

“Estrogen is very potently anti-androgenic, [which] kind of outweighs any difference in the progestins related to their androgenicity. ...If you take estrogen in a birth control pill, you’re gonna drop your testosterone quite a bit. So if you have hormonally sensitive acne, it’s gonna get better whether you take a pill with a second, third, or fourth generation progestin.”

Although they definitely can work, Dr. Davis remains sceptical of the marketing around certain pills as acne treatments. “If [drug companies] can show that their medication works for acne, they can market it for acne. ...And then they can say, here’s our new pill, we tested it for [acne], and the FDA gave its seal of approval.” That brings in new users and more money.

We don’t know for sure if one of these FDA-approved pills is better than the rest at treating acne. We just know they’re better than placebo. All the data we have on varying androgenic effects comes from hormone receptor binding assays in cell cultures, not head-to-head clinical trials on living subjects. “No drug company wants to pay for a study where they’re gonna lose,” as Dr. Davis puts it. So while anecdotal evidence suggests that people with acne might be happier with a newer progestin like norgestimate or drospirenone, it’s not a hard and fast rule.

If your periods are unbearable, there’s probably a pill that can help

The pill was initially marketed as a treatment for so-called “menstrual dysfunction” because birth control was pretty taboo in the early 60s, but also because that’s technically its primary function. Combination pills prevent ovulation, which also means that they prevent menstruation. The pill lets you control your period — not the other way around.

No other birth control method can touch this. Progestin-only pills prevent fertilization but not necessarily ovulation, which can cause unpredictable bleeding. Hormonal IUDs — which contain the progestin levonorgestrel, but no estrogen — totally stop menstruation for some people, but not everyone. (The same goes for the shot and implant, which are, you guessed it, also progestin-only methods.)

Copper IUDs work by causing constant low-grade inflammation in your uterus, which means they can cause even heavier, more painful periods. But the right combination pill (or patch or ring) makes your periods lighter and easier, and lets you choose when you bleed; if you’d just as soon never have another period in your life, it can do that, too.

For people with endometriosis, premenstrual dysphoric disorder (PMDD), poly-cystic ovarian syndrome (PCOS), irregular periods, or cramps severe enough to keep them out of work, the pill is seriously life-affirming medication.

We’ll probably never know for sure how the pill affects mood

In recent years, more and more attention has been focused on the link between hormonal contraception and mental health. So, once and for all: does the pill cause depression — and if you already have it, can it make it worse?

There’s no clear answer to this. One 2016 Danish study found that oral contraceptive use was associated with a higher likelihood of antidepressant use and a first diagnosis of depression, particularly amongst adolescents.

However, this isn’t exactly ironclad proof. This study was observational, which means it examined an extremely large data set of health outcomes, controlling for certain factors like age, sex, location, and certain diagnoses. “Large data sets are great for having enough people in your study to look for small effects, but what they’re not good for is ascertaining anything about the individual person in the study,” Dr. Davis says.

This means you can identify the incidence of depression diagnoses, but not necessarily every other contributing factor besides contraceptive use. “If you don’t know about the person’s family history [or] their baseline mental health ... you can’t really figure out all the other things that might also be affecting that person’s risk of depression.”

It’s totally plausible that hormonal medication could influence our moods, but proving it in a clinical setting is almost impossible. Long-term, double-blind trials are incredibly expensive, and even if they were to get funding, they’d still have to combat confirmation bias and placebo effects — both of which are particularly strong with oral contraceptives.

You might associate placebo effects with positive outcomes, but as Dr. Davis explains, it also goes the other way. Negative placebo effects called “nocebos” crop up consistently in birth control trials: “[In] some older studies, [subjects] got an inert pill or an active pill, and plenty of [people] who took the inert pills got side effects. They were usually the same types of side effects and the same frequency as the people taking the real thing.”

Perhaps more than anything, she thinks that this shows just how much of our everyday emotions we’ve learned to attribute to birth control, noting that “[we’ve] been trained from a very early age to identify certain feelings as ‘hormonal.’” After all, if you’re already primed to feel something, you’re more likely actually feel it — so the more you read about certain side effects online, the easier it gets to conclude that your pill is causing them.

All of this makes it extraordinarily difficult for pill users to figure out if a mood change is just a mood change, or if it’s somehow related to their medication. Both you and your doctor need to be able to trust your symptoms and think critically about what could be causing them.

“I’ve heard a lot of different anecdotes about people having changes in their mental health based on what types of contraceptive they’re using,” says Dr. Brandi, “[and] I believe the people who are having these symptoms.” She says the best way to deal with this is to discuss it openly with your doctor so they can adjust your dose or change formulas if appropriate: “If someone is having side effects from one pill, it doesn’t mean that all pills will cause it for them, but they may need a lower dose or a different progestin.”

How to find the right pill

A terrible first pill experience has a way of turning people off it for life. Here’s what you need to know to minimise the chances of that happening.

Consider your period

All pills reliably prevent pregnancy, so if you want to find one that alleviates specific menstrual symptoms, your provider needs to know as much as possible about your cycle. Here are just a few of the questions Dr. Davis is likely to ask her patients:

“How much do you bleed? Do you have pain? Do you wanna see [your period] every month? Would you be fine if you didn’t? Would you prefer not to? Would you like to see it once in a while, or would you be fine if you never got your period? Would you like to never get a period?”

Based on the answers to those questions, she’ll figure out a starting point: “Let’s look at the way the pills are formulated and pick one where you’re most likely to get [the effects] you’re looking for.”

If your period is no big deal, most pills will probably work for you. But if it’s truly horrible, a pill that prevents ovulation and minimises the number of periods you have — or stops them entirely — will probably be more helpful. This is usually accomplished by choosing a pill that’s formulated with more active pills per pack than the standard 21.

Some pills have 24 active pills, while others let you go 3 months before you get a placebo pill, and therefore, bleeding. You don’t necessarily need a special pill to do this, though: as long as you talk to your provider about it first, you can skip periods by just skipping the placebo pills and starting a new pack. It’s perfectly safe, although some people prefer to have a monthly period as a confirmation that they’re still not pregnant.

Don’t expect too much — or too little

Whenever you start a new pill, the absolute best thing you can do is let go of any preconceived notions you have about the side effects it may or may not cause. It usually takes 3-6 months for your body to fully adjust, and while you can rest assured that you won’t get pregnant, any other side effects will remain a mystery until you try it.

If that sounds frustrating, well, it certainly can be — but here’s how Dr. Davis thinks about it: “There’s nothing special about that,” she says, laughing. “I mean, that’s medicine.”


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