In 2023 a company called Rescripted did a little sleuthing. They sent out a survey among 1,000 participants to see exactly how well we’re doing on the topic of Sex Ed. Basically, a little pop quiz.
If we’re continuing with this quiz metaphor, let’s just say… the class did not pass. Among the study’s results, it showed that porn is the number one source of information about sex, 34 percent of people believe that those wearing a tampon can’t pee while the tampon is inserted, only 18 percent of people feel educated about their own hormones, and only 35 percent have any idea what’s going on during their menstrual cycle.1
If you’re reading this thinking, “Well I don’t have any idea what’s going on in my cycle,” hey, it’s not you—most of us grew up with little to no proper sex education. In fact, research shows that in areas with more poverty, about 76 percent of girls have never even heard of menstruation before it actually begins.2 So, we’re not exactly set up for success.
That’s why we’re going to go back to the basics. Here, we’ll take a look at the four phases of the menstrual cycle and how these phases are altered when you’re using hormonal birth control.
The Four Stages of Your Menstrual Cycle
Let’s be real: One of the reasons so many people are uninformed about their own menstrual cycle is that a lot of the information out there is researched and written by those who have never had a menstrual cycle. In fact, it took an extra effort to even find a source written by a female for the below information.
According to Dr. Diane I. Meisles, an OBGYN, it’s a common misconception that the term “menstrual cycle” only refers to the days a woman gets her period.3 Instead, the menstrual cycle is broken up into four stages:
1. Menstruation:
This is the time during your cycle when you bleed. If you didn’t get pregnant the previous month, your uterus sheds its lining in the form of blood and tissue (your period). Day one of your period is considered day one of your menstrual cycle.
2. Follicular phase:
As soon as you start your period, you’re also starting the follicular phase of your cycle. This phase lasts on average about 14 days (but can be shorter or longer), until ovulation occurs. During this phase, the brain releases follicle-stimulating hormone (FHS) which helps eggs grow in your ovaries, and estrogen—lots of estrogen. All of this is prepping your body for a possible pregnancy.On a side note, with estrogen being the dominant hormone, serotonin also increases. So during this phase you might feel more turned on, energized, productive, and positive.4
3. Ovulation:
Ovulation usually happens around the middle of the menstrual cycle. So, if you tend to get your period on day 28, ovulation would occur on about day 14. This is when a mature egg is released from one of the ovaries and makes its way down the fallopian tube, so it can be fertilized by sperm. If the egg is fertilized during this time, it attaches to the uterine lining and voila—you have the start of a pregnancy. If you don’t get pregnant during this window, you can expect to have your period.
4. Luteal phase:
After ovulation, a special little structure called the “corpus luteum” is formed in the ovary. This cyst releases hormones like progesterone that prepare the uterus for a possible pregnancy. The uterus makes its lining all thick and ready to nourish a growing fetus if the egg gets fertilized.
If the egg isn’t fertilized during ovulation, though, this corpus luteum breaks down and progesterone levels plummet. This lets the body know it’s time to shed that thick uterine lining—and this is when you get your period. On a side note, during the luteal phase you’re more likely to feel tired, anxious, depressed, and have a lower libido.5
Despite what your gym coach may have told you in Sex Ed, you are more likely to get pregnant at certain times throughout the menstrual cycle. You’re most fertile in the days surrounding ovulation. And this is actually how hormonal birth control works: It stops ovulation from happening.
How Does Birth Control Change My Cycle?
Most people on oral birth control pills are taking what’s called a “combination pill,” which includes both progesterone and estrogen. (A smaller portion of people are taking a progesterone-only pill.) With the combo pill, you typically take it every day for three weeks, and then have one week of placebo pills. During this week of basically sugar pills, you’ll bleed, sort of like a regular period.
Here’s what’s really going on: The pill replaces your menstrual cycle with an “artificial cycle.” This means for three weeks, your estrogen and progesterone levels are high—communicating to the body, “Hey, I’m already pregnant. No need to ovulate.” And then during the week of placebo pills, these hormones drop dramatically, inducing “breakthrough bleeding.”7
These days there are a variety of hormonal birth control pills available– some with three weeks of pills and one week of placebos, and others that you simply take continuously for months on end, to avoid having breakthrough bleeding for up to a year.8
Do I Have a Normal Period on Birth Control?
Depending on the type of birth control you use, your period may be shorter, lighter, longer, or heavier. For example, if you’re taking progesterone-only oral pills, you’re more likely to have some irregular spotting during non placebo days. As your body gets used to either type of pill, you may experience some shorter and lighter periods. In fact, some people get on birth control in the first place because it can shorten periods, make them lighter, and may reduce cramping and other PMS symptoms.9
What Does my Cycle Look Like with an IUD?
There are two main types of IUDs: a copper (non-hormonal) IUD and a progestin IUD. With a copper IUD, your hormones are not being altered, so you’re actually having a regular menstrual cycle each month, including all four phases. Copper IUDs prevent pregnancy, not by stopping ovulation, but by preventing the sperm from reaching the fertilized egg. Copper IUDs can cause spotting in between periods and possibly heavier, longer, and (sorry) more painful periods—especially for the first several months.8
Progestin IUDs also block the sperm from reaching an egg, but may also prevent you from ovulating (releasing an egg) in the first place.10
With a progestin IUD, spotting between periods and irregular periods are pretty common within the first three to six months. Over time, a lot of women have lighter or even zero periods on progestin IUDs.8
What Does My Cycle Look Like with Injected or Implanted Contraceptives?
The contraceptive implant looks like a small, flexible, plastic rod that is inserted under the skin of the upper arm.11 A contraceptive injection is a prescription medication, usually given every 12 weeks in the form of a shot.12 Both of these work by increasing the body’s levels of progesterone, which stops ovulation and thickens cervical mucus. This means, no ovulation. It also means after about a year of use, you’ll probably stop having periods altogether. In the first year, though, you can expect some irregular and unpredictable bleeding.8
Is It Healthy to Not Have a Period on Birth Control?
According to Mayo Clinic, withdrawal bleeding is not the same thing as having a period, and it’s not absolutely necessary for your health. This means if you’re taking a hormonal birth control pill that limits the number of times you bleed, or are using an IUD that prevents bleeding, it should be fine as long as you’ve discussed this with a trusted physician.13
That said, the topic is still controversial among doctors. So, if you’re seeking a life with less time bleeding, be sure you run it by your doctor first—and don’t hesitate to ask them everything you need to in order to truly understand your cycle.
A note on sex and gender: Sex and gender exists on spectrums, and this article uses terms like “male” or “female” to refer to sex assigned at birth. Learn more.
