Thinking you can’t get pregnant if you have sex during your period is a common misconception, stemming from a combination of misperceptions and inconsistent education around fertility and a women’s menstrual cycle. While most women are unlikely to get pregnant during their period, it can still happen.
Whether you’re actively trying to conceive or aiming to prevent pregnancy, here’s what to know about the chances of getting pregnant while on your period.
What Are the Chances of Getting Pregnant If I Have Sex on My Period?
The chances of getting pregnant while on your period are relatively low. Because there’s widespread understanding that this is a less fertile window, there’s limited research on the probability of conceiving while on your period — as researchers are more likely to prioritize studying periods of higher fertility.
As a result, it’s hard to quantify the likelihood of getting pregnant. However, it can still happen.
[Read: Fertility Diet: What to Eat If You Want to Get Pregnant Faster]
In general, the chances are higher than you think, says Dr. Octavia Cannon, a board-certified physician and provider at Alliance Obstetrics and Gynecology in East Lansing, Michigan.
The two main reasons why you could get pregnant if you have sex during your period are irregular menstrual cycles and menstrual cycle variability.
Irregular menstrual cycles
It’s not always possible to predict when you’re going to ovulate, and timing may vary. Factors such as stress, illness or lifestyle changes and medical conditions can influence the timing of ovulation. Women with irregular menstrual cycles, oftentimes attributed to conditions like polycystic ovarian syndrome, may experience unpredictable ovulation.
For example, if a woman has PCOS, which makes your period irregular, then it might increase your chances of getting pregnant if you have sex on your period. However, it may also decrease your chances because you’re not ovulating or you’re experiencing unpredictable ovulation.
Some people may experience vaginal bleeding and think it’s their period, but it’s not their period. If someone is bleeding between their cycles or bleeding at the time of ovulation, it can be due to other factors, such as:
— Health or medical conditions
— Medications
— Hormones
— Injury
— Infection
As a result, it is possible to get pregnant during this time.
Menstrual cycle variability
A normal menstrual cycle is every 21 to 35 days, and the average cycle is every 28 days.
“The most fertile time of a woman’s cycle is around two weeks before the next period comes or days 12 through 21 after the first day that they bleed,” Cannon says.
Women with shorter menstrual cycles may be at higher risk for getting pregnant during their period because they likely ovulate closer to the time they have their period.
The day of ovulation is not the only day that women are fertile.
While a sperm can live within a woman’s body for up to five days, an egg can survive between 12 to 24 hours after ovulation. That means you can become pregnant if you have sex five days before ovulation or one day after ovulation, giving you a six-day fertile window.
[READ: Pregnancy After Miscarriage.]
How Ovulation Works During Your Period
Ovulation occurs when a mature egg is released from either ovary, which then moves down the fallopian tube, ready to be fertilized. For someone with a regular menstrual cycle, ovulation typically occurs approximately once per month.
Your menstrual cycle has four phases:
— Menstruation
— Follicular
— Ovulation
— Luteal
Pregnancy is most likely to occur during your fertile window, which occurs in the days leading up to and around ovulation. Your ovulation phase typically occurs in the middle of a menstrual cycle, not during your period phase.
However, individual menstrual cycles vary, and several factors can influence when you ovulate.
Can you get pregnant on the fourth day of your period?
You can get pregnant anywhere during your cycle, whether on your first day or your third day.
The length of the woman’s cycle plays a part.
“If they have short cycles or their cycles are irregular, then they are really most vulnerable to doing that,” Cannon says.
Can you get pregnant the day before your period?
It’s unlikely that you’d get pregnant the day before your period, but it’s possible. The probability will vary based on your menstrual cycle length and regularity, which affects when you ovulate.
“An egg lives for 12 to 24 hours unfertilized, and sperm or semen can live in the woman’s vagina for three to five days. They’re persistent,” Cannon says. “Because of that, you literally could fall in that window where the period is or say you’re at the end.”
Can you get pregnant right after your period?
Especially if you have shorter menstrual cycles, you may be more likely to get pregnant if you have sex toward the tail end of your period than someone with a longer menstrual cycle.
“If you have a prolonged period, meaning it’s lasting more than seven days and your periods come frequently, then you’re at risk of getting pregnant,” says Dr. Adi Davidov, vice chair of the department of OB-GYN and director of gynecology at Staten Island University Hospital in New York.
[Read: How to Find a Good Fertility Clinic.]
If You Get Pregnant, Will Your Period Stop?
One sign of pregnancy is that you will no longer have a menstrual cycle as your body undergoes hormonal changes. Some women may experience light bleeding or spotting at the beginning of a pregnancy, which could be confused with a period.
“It’s probably because you were already pregnant, and it’s what we call implantation bleeding,” Cannon says. “That’s when the fertilized egg is trying to implant into the uterine wall or in the uterus.”
[Related:What Is Male Birth Control?]
Ways to Prevent Getting Pregnant During Your Period
Although the likelihood of getting pregnant during menstruation is generally lower, it is by no means nonexistent. Menstruating is not a reliable method of birth control, and neither is the “pull-out and pray” method of withdrawing before ejaculation. That’s because sperm can still be released before the man ejaculates, which increases risk for pregnancy.
If you’re looking to prevent pregnancy — no matter what time of the month it is — it’s essential to use a reliable form of contraception. Some reliable methods of birth control include:
— Hormonal methods: Oral contraceptives, hormonal patch, vaginal ring, injections or shots
— Long-acting reversible contraceptives: Intrauterine devices, hormonal implants
— Barrier methods: Condoms, diaphragms
— Female or male sterilization: Male vasectomy, female tubal ligation or occlusion
Effectiveness of different methods can vary, so it’s important to do your research and consult with a health care provider when choosing the best birth control method for you.
“It’s always important to know your body,” Cannon says. “If you don’t know your body, know how to find the answers to your questions.”
Appointments go quickly, so writing down a list of questions and concerns can help ensure that you ask the right questions and get the answers you need in the rush of the visit.
More from U.S. News
Understanding Fertility: What Happens During Ovulation
Fertility Diet: What to Eat If You Want to Get Pregnant Faster
Can You Get Pregnant on Your Period? originally appeared on usnews.com
Update 06/21/24: This story was previously published at an earlier date and has been updated with new information.
