Managing your period and contraception

From Learn about your cycle. General wellness information, not medical advice. Sources.

Period products

There's no single best product for everyone, and anyone who says there is is probably selling something. That doesn't make them all the same, though. They differ in cost, how much waste they create, what they're made of, and how well they suit your body and your flow. Here's a fair look at each one and its trade-offs, so you can find what fits you.

One safety note up front. Toxic shock syndrome (TSS) is a rare risk tied to internal products (tampons, cups, discs), and it comes from high absorbency and leaving something in too long rather than from the products themselves. External products carry a small risk of skin irritation instead, not TSS.

Tampons sit internally and absorb flow. Use the lowest absorbency that handles your flow, and change every four to eight hours, never more than eight. They're cheap and everywhere. Because they're single-use, though, the cost and the waste keep adding up.

Menstrual cups are a flexible silicone cup that seals with light suction, then gets emptied and rinsed. They hold more than a tampon and leak about as much or less. There's a learning curve of a few cycles, and fit can depend on your anatomy, but one cup can last years, which makes it very cheap and low-waste over time.

Menstrual discs sit a little differently inside and suit a range of anatomies. They hold the most of any product, which helps on heavy days. They come disposable or reusable. Good independent research on discs is still thin, so some of what's claimed about them rests on the makers' own information.

Disposable pads are the familiar option: absorbent, external, no learning curve. Change every few hours. There's no TSS risk. The main thing to watch is skin irritation, which fragrance-free versions help with.

Period underwear looks like normal underwear with an absorbent layer built in, then you wash and reuse it. It's comfortable and low-effort, though it costs more upfront and needs time to dry. One thing to know: some brands have been found to contain PFAS ("forever chemicals"), and a well-known brand settled a lawsuit over its marketing claims. The presence of these chemicals isn't the same as proven harm, but it's a fair thing to weigh if it matters to you.

Reusable cloth pads snap around your underwear and get washed and reused. They're low cost and low waste over time. The main practical hurdle is washing them and getting them properly dry.

Free bleeding means using nothing at all, sometimes onto dark or absorbent clothing. It's a comfort, cost, or personal choice. There's no built-in health risk as long as you wash regularly. The practical limits are staining and managing flow out in the world.

On cost and the planet. Disposables are a recurring spend. A set of reusables is one cost that lasts years and, over five years, tends to work out cheaper. Disposables also add up to a lot of plastic waste over a lifetime. Reusables cut that waste but shift some of the footprint to manufacturing and to the water and energy of washing. Most lifetime-total figures you'll see quoted are rough estimates, so hold them loosely.

What's in them. Researchers have found traces of chemicals of concern in nearly every kind of period product, disposable and reusable: plastic additives like phthalates, fragrance chemicals, and, in one study of pads, tiny plastic fibers shed from every pad tested. Finding something in a product isn't the same as showing it gets into your body or causes harm, and that hasn't been shown yet. But whether these products affect health over the long term is still largely unstudied, even though most people who menstruate use them thousands of times over a lifetime. That fits a long pattern of period health getting little research attention (more in Why so much of this was never studied). If you'd like to lower your exposure, fragrance-free products are an easy step.

A note on access. Not everyone can reliably afford or reach these products. Period poverty is real, it pushes people toward makeshift materials, and it affects whether people can go to school or work. It's a matter of basic dignity, not a lifestyle choice.

Your birth control options

This is a tour of the options, not a recommendation. There's no single right choice, and the person who can help you match a method to your health history is a clinician or pharmacist. Nothing here is a prescription.

The methods

The numbers below show how many out of 100 people get pregnant in their first year of using a method the way people really use it, missed pills and late shots included. That's not how often the method itself breaks. It's what happens over a year of real life. Used perfectly every time, most methods do better, so the gap tells you how much a method depends on you.

The most effective options are the ones you don't have to think about day to day: the implant, the hormonal and copper IUDs, and permanent methods like tubal ligation and vasectomy. Fewer than 1 in 100 people using them get pregnant in a year.

In the middle sit the shot (about 4 in 100) and the pill, patch, and ring (about 7 in 100). These work well but depend on you keeping up with them.

The least effective in typical use are external condoms (about 13 in 100), the diaphragm and the sponge (about 17), internal condoms and spermicide alone (about 21), the cervical cap (about 22), withdrawal (about 1 in 5), and fertility-awareness methods, which range widely from about 2 to 23 depending on the method and how closely it's followed.

Hormonal methods and your cycle

Worth knowing if you love the Inner Seasons idea: combined hormonal methods (the pill, patch, and ring) largely switch off the natural hormone swing the seasons are built on. In a natural cycle, a period comes after ovulation, when your own hormones fall. Combined methods usually stop ovulation, and their steady hormones keep the lining thin. The bleed you get during the hormone-free or placebo days happens because the method's hormones drop for a few days, which makes that thin lining shed. So it's called a withdrawal bleed rather than a true period, and it's usually lighter and arrives on a more predictable schedule. (There's more on the natural version in How your cycle works.) If you're on one of these, tracking your bleed and your symptoms will serve you better than tracking seasons that aren't really turning.

Progestin-only methods (the mini-pill, the shot, the implant, the hormonal IUD) tend to make bleeding unpredictable or lighter, and sometimes stop it altogether. That's expected, and fine in itself. Two specifics worth flagging: the shot can delay your return to fertility by several months after you stop, and the copper IUD, which is hormone-free, often makes periods heavier and crampier, especially at first.

If you take thyroid medication, it's worth knowing that the estrogen in combined methods can change how much of it you need. Mention it to your prescriber when you start or stop one, so they can decide whether to recheck your levels.

How well studied is all this? It depends on the question. The pill has some of the longest follow-up in medicine. One UK study tracked about 46,000 people for up to 44 years and found no lasting increase in cancer or in overall risk of death, along with lower rates of some cancers. Breast and cervical cancer risk was slightly higher during use and faded within about five years of stopping. Those were older, higher-dose pills, though. Fertility is well studied too: most people who stop a method and try to get pregnant do so within a year, at similar rates for hormonal methods and IUDs.

Other questions have had much less attention. The largest studies of mood have come only in the last decade, decades after the pill arrived. One very large Danish study linked hormonal methods with a higher chance of starting antidepressants, especially in teens, though a link isn't proof of cause. Newer methods have far shorter track records, and the body-wide effects of living with a copper IUD for many years have had little study. That's part of a wider gap in research on bodies that menstruate (more in Why so much of this was never studied).

Combined methods carry a small clot-related risk that a clinician screens for. That's exactly why method choice is a conversation with a professional rather than something to settle alone.

One method that also protects against STIs

Condoms, external and internal, are the only methods on this list that also reduce the spread of STIs and HIV. That's worth remembering whatever else you use.

What can make your birth control less effective

A few things can quietly lower how well hormonal birth control works, and some aren't obvious. St John's Wort, a common over-the-counter supplement for mood or sleep, is a notable one: it can reduce the pill's effectiveness and cause breakthrough bleeding. Certain prescription medicines do the same, including some epilepsy medicines and the antibiotic rifampin (most antibiotics do not, despite the common belief). And if you throw up soon after taking a pill, or have a bad stretch of diarrhea, your body may not fully absorb it. None of this means stopping anything. It just means it's worth mentioning your birth control to a pharmacist or prescriber when something new comes up, and using backup if you're not sure.

The inexact science of cycle prediction

Predicting a cycle is inexact by nature. Our estimate comes from your own logged history, and it gets better the more you log, but no prediction can be exact: bodies aren't clockwork, and cycles shift from month to month, more so if yours tend to vary. That's why we show a likely window rather than a single certain date, and why the estimate gets fuzzier the more your cycles move around.

It also means the fertile-window estimate in Moonstrate, or in any cycle tracker, is not birth control. It's a calendar guess, and calendar guesses are the least reliable end of family planning. Properly practiced fertility-awareness methods are far more rigorous, because they add daily body-sign tracking and real discipline around the fertile window. Don't lean on an app estimate as protection.

Emergency contraception

Emergency contraception comes in a few forms: levonorgestrel pills (such as Plan B), ulipristal acetate (ella), and the copper IUD, which is placed by a clinician and then keeps working as ongoing contraception. Levonorgestrel pills are meant for the first 3 days (72 hours) after sex. Ella works for up to 5 days and holds up better toward the end of that window, and the copper IUD can be placed within about 5 days and is the most effective of the three. Whichever one is used, the sooner the better. Access varies a lot from place to place, though. Whether something needs a prescription, what pharmacies stock, and local laws all differ between countries, and in the US from state to state, and they can change, so it's worth checking what's available where you are. This is here as information, not a recommendation, and a pharmacist or clinician can tell you your options and how to get them locally.

One thing that's easy to get wrong: emergency contraception prevents pregnancy before it's established. It is not an abortion pill, and it works differently from one. You may also have heard that Plan B stops working above a certain body weight. But that isn't settled: earlier studies pointed that way, more recent ones muddied the picture, and regulators haven't agreed on a limit. If you're unsure whether it's the right option for you, a pharmacist can help you sort it out quickly.

Finding current information where you are

Laws and access around birth control, emergency contraception, and abortion change often, and they differ a lot between countries and, in the US, from state to state. Rather than list rules here that could be out of date by the time you read them, here are groups that track them closely.

US state laws: the Guttmacher Institute tracks state laws on birth control, abortion, and sex education, at guttmacher.org.
Abortion laws around the world: the Center for Reproductive Rights maps them country by country, at reproductiverights.org.
Legal questions in the US: the Repro Legal Helpline answers legal questions about pregnancy, birth, parenting, and abortion, free and confidential whatever your age or immigration status, at reprolegalhelpline.org.
Medical questions: the M+A (Miscarriage and Abortion) Hotline offers free, private support from doctors and nurses for questions about miscarriage or abortion pills, at mahotline.org.

If you're looking this up somewhere it isn't safe to, a private browser window and an encrypted messaging app are good habits. Your data and privacy has more on what actually puts people at risk.

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