Confused about birth control? Who could blame you? With so many options available, making a choice can be seriously overwhelming. But take heart: According to experts, the seemingly endless array of options is actually a good thing.

“The average woman spends five years of her life trying to get pregnant, being pregnant, and breastfeeding,” says Kate White, MD, MPH, assistant professor of obstetrics and gynecology at Boston University. “Which means the average woman spends about 25 to 30 years trying to avoid pregnancy. That’s why it’s good to know there are so many options available; some methods might be better at certain times of your life compared to others.”

Many of the most popular birth-control options contain hormones in the form of pills, patches, or implants. But these methods aren’t just used to prevent pregnancy; some women also rely on them to regulate otherwise irregular cycles or to treat other health issues under the careful supervision of a doctor.

Whatever type of birth control you’re considering for whatever reason, it’s important to understand your options and know how each one can affect your cycle. Brush up on the basics below.

Hormonal methods of birth control use estrogen and/or progestin to impede pregnancy by preventing ovulation, thickening your cervical mucus to help block sperm from fertilizing the egg, or thinning the uterine lining so it’s unlikely for a fertilized egg to implant there.

So how’s a woman to make a choice among all the different options? “The effectiveness of the birth control is one of the many things that matter for a lot of women, in addition to how it affects their periods, how private it is, if they can stop and start it on their own, etc.,” says White. “All of these things might be equally important to you, so don’t let a doctor tell you it’s all about effectiveness. You need to live with your birth-control method every day, including days you’re not having sex. Find one that fits your life and lifestyle.”  

Here’s a breakdown of three kinds of self-controlled hormonal contraceptives. Keep in mind that each type carries specific risks, so it’s important to go over any potential side effects with your doctor before deciding.

• Injectable birth control: This involves getting a shot of progestin in the arm or buttocks once every three months. (Rate of effectiveness with typical use: 94 percent.)

• Progestin-only pills (POPs): These once-daily pills interfere with ovulation and thicken the cervical mucus, which makes it hard for sperm to enter the fallopian tube or uterus. They can cause unscheduled bleeding between periods because they alter normal cyclical changes. (Rate of effectiveness with typical use: 91 percent.)

• Combined hormonal methods: These include pills, patches, and rings that combine synthetic estrogen and progestin to thicken cervical mucus and inhibit ovulation. These carry a risk of blood clots that other hormonal methods don’t have. (Rate of effectiveness with typical use: 91 percent.)

  • Combined oral contraceptives (COCs, otherwise known as “the pill”): COCs are usually taken once a day, but there are a variety of different kinds. Your doctor can walk you through your options.

  • Contraceptive patch: A thin, plastic patch is placed on the lower abdomen, buttocks, upper body, or outer arm to release hormones through the skin and into the bloodstream. Xulane is currently the only FDA-approved patch available in the U.S.

  • Vaginal ring: A thin, flexible ring is inserted into the vagina where it releases hormones for three weeks at a time. The NuvaRing is currently the only FDA-approved ring available in the U.S.

No matter what type of hormonal birth control you use, the hormones in the pills, patch, or ring will take control of your cycle and change your periods. Every woman is different, but common side effects can include bleeding between periods (spotting or “breakthrough” bleeding) or lighter periods. Some women stop getting periods altogether. That’s because hormonal birth control can prevent ovulation and keep the uterine lining from getting thick.

If you do get monthly bleeding while using hormonal birth control, it won’t technically be a “period.” Unlike menstruation, which occurs when your own hormone levels naturally drop off, the bleeding you get on birth control is called “withdrawal bleeding” and it usually happens during a one-week break in your pill, patch, or ring regimen.

Patch users wear a patch for a week at a time before removing and swapping in a new patch (this is done for three consecutive weeks in a row). Rings are left in place for three weeks at a time. At the end of three weeks, the patch or ring is removed, allowing for withdrawal bleeding on the fourth week.

Pills generally include one week of placebos for the same reason. Bleeding may start at different times in your cycle depending on the type of birth control you take, but it can be common for it to start on the second or third day of the placebo pills (or the week without a patch or ring). But, as always, this can vary from woman to woman and can also change over time.  

LARCs can be inserted directly into the uterus or implanted under the skin and they’re considered over 99 percent effective in preventing pregnancy. “These methods are so effective because they’re ‘set it and forget it,’” says White. “You don’t need to do anything, and the method keeps working for you every day!” Here’s how:

• An intrauterine device (IUD) or intrauterine system (IUS) is a small, T-shaped device that’s inserted into the uterus by a healthcare provider. IUDs can stay in place for three to 10 years at a time and come in two different forms:

  • Hormonal IUDs release progestin (synthetic progesterone) into the uterus to thicken the cervical mucus and thin the uterine lining. At times, they may even prevent the ovaries from releasing eggs. These devices affect your period in the same way all forms of hormonal birth control do—the hormones take over your own body’s hormones and can shorten, lighten, or eliminate your monthly bleeding.

  • Copper IUDs work by preventing sperm from fertilizing the egg, and in the rare instances that fertilization does occur, the device keeps the fertilized egg from implanting in the uterus. Since the copper IUD doesn’t include hormones, the timing of your period will likely remain consistent with what it was like before you got the IUD, although some people report heavier/longer periods and more intense menstrual cramps, especially in the first few months of use.

• An implant is a matchstick-sized, flexible plastic rod that is surgically placed under the skin of the upper arm to release progestin. It can stay in place for up to three years. “The implant works similarly to the birth-control pill,” explains White. “It stops ovulation and causes changes in the cervical mucus and lining of the uterus to make pregnancy less likely.”

The copper IUD and emergency contraceptive pills (ECs or “the morning-after pill”) may be used to prevent pregnancy after unprotected intercourse or if a condom breaks.

• The copper IUD is the most effective type of emergency contraception and must be inserted within five days of unprotected sex.

• ECs are hormonal pills that are usually taken as one single dose. When these pills are taken before ovulation, they thicken the cervical mucus and can delay or inhibit ovulation for at least five days, allowing time for any sperm in the uterus or fallopian tube to die. Pregnancy may still occur if the pills are taken after ovulation.

If you take ECs to prevent pregnancy, you should still have a normal period within the next month, although your period may arrive earlier or later than normal. Some women also experience unexpected spotting. If you’re period hasn’t come within six weeks of taking ECs, it may be time to take a pregnancy test or visit your doctor. And remember, none of these birth-control methods offer protection against sexually transmitted infections, so keep condoms handy.