Can You Get Pregnant Without Having a Period?

Ovulation When You're Not Getting Your Period

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If you're not getting your periods, it's unlikely that you'll be able to get pregnant. But it's not impossible. Darunechka/iStock

Can you get pregnant without having a period in months? Yes, it’s possible. But it’s not likely. If you’re not getting your periods, this is a good reason to see your gynecologist. There are some normal—and some not-so-normal—reasons this can occur. What could cause you not to get your periods? Could you be pregnant and not know it?

What do your periods have to do with getting pregnant? And, if you want to get pregnant, how can your doctor help you conceive if you’re not menstruating?

What Does Your Period Have to Do With Getting Pregnant?

Your period is the most obvious sign that your body’s reproductive system is at least trying to operate. It marks the end of one menstrual cycle. The female reproductive system is complex, and while you could read a detailed explanation of how it all works, here is a quick and simple breakdown of what happens every month (if you’re getting your periods).

At the start of your monthly cycle, specific hormones tell your ovaries to start developing an egg. The egg, or oocyte, is contained inside a follicle. This follicle is like a tiny bubble. Fluid, nutrients, and the immature egg are contained inside the follicle.

The hormones stimulate the follicle and egg to grow. This goes on for about 12 to 14 days, though the number of days can vary. Eventually, the egg reaches maturity. The follicle bursts open, and the egg is released from the ovary.

This is called ovulation. The egg only lives for 12 to 24 hours.

If you have had sexual intercourse within five days of ovulation, there may be sperm waiting in the reproductive system. The egg has a short lifespan, but sperm can survive in the female reproductive system for up to five days. Sexual intercourse on the actual day of ovulation, and even the day after, can also lead to conception.

If a sperm cell fertilizes the egg, you will become pregnant.

After ovulation occurs, the hormone progesterone triggers the lining of your uterus to prepare for a fertilized egg, or embryo. The lining of the uterus is called the endometrium. For the next 10 to 15 days, the endometrium will build up, becoming thicker and changing its physiological structure to be just right for an embryo.

If you conceived, an embryo will implant itself into the uterine lining between seven and 10 days after ovulation. This will trigger different hormones to prepare the body to nurture a pregnancy. If you didn’t conceive, the hormone progesterone will begin to drop. Lowering levels of progesterone will eventually signal the endometrium to break down and expel itself. This is your period.

As the endometrium is expelled, your body starts releasing hormones to trigger the next month’s ovulation, assuming you’re having regular cycles. Your period marks the ending of one cycle. If you get your period, it is likely (but not certain) that you ovulated within the past two weeks. Ovulation is required to get pregnant. If you’re getting your periods regularly, you are most likely ovulating regularly.

Can You Ovulate Without Getting Your Periods?

If you are not getting your periods, you are probably not ovulating regularly.

There are a number of reasons this may occur (more on that below). However, this doesn’t mean you won’t suddenly ovulate without getting a period first.

As mentioned above, menstruation marks the end of one cycle. If ovulation occurs, and you don’t conceive, you will get your period. But let’s say you are currently not having regular cycles. You could, depending on the reason why you’re not menstruating regularly, suddenly start a menstrual cycle.

The end of your cycle is marked by your period starting, but there are no obvious signs that your body has begun a cycle. You can ovulate and not know it.

You will only know you ovulated if you get your period or, if you had sexual intercourse within your fertile window, you get pregnant.

You may not realize you’re pregnant for awhile, though, since you haven’t been getting your periods. You won’t have a period to be “late” if you haven’t been getting one.

13 Reasons You May Not Be Getting Your Periods

The medical term for a lack of menstrual cycles is amenorrhea. What could be the reason you’re not getting your periods?

1. You may be pregnant. If you have had regular periods, and then suddenly stop getting your period, you may be pregnant. This is likely the first thing you thought of when your period was late, and you have likely already taken a pregnancy test.

But what if your pregnancy test was negative? Could you still be pregnant? Yes. It’s unusual, but it is possible to be pregnant and get a negative pregnancy test. See your doctor for follow-up and confirmation, and until you know otherwise, act as if you’re pregnant (avoid ​alcoholic drinks, for example).

2. You’re breastfeeding. Exclusively breastfeeding a baby can prevent your periods from coming. This is sometimes called “breastfeeding clean.” How long will you go without a period when breastfeeding? It depends on how often you are breastfeeding and your personal biology.

3. Your chosen method of birth control has stopped your periods. Some forms of birth control can stop your periods. Your doctor should have told you if this was possible when they prescribed it.

How long will it take for your periods to return after you stop taking the birth control? It depends on your body and your contraception choice. With the Depo-Provera, also known as the “birth control shot,” menstrual cycles tend to return about six months after the last injection (if you were receiving the injections for at least one year).

4. A medication you're taking has stopped your cycles. Birth control isn’t the only medication that can stop your periods. Other medications that may stop your cycles include some psychiatric drugs, chemotherapy, allergy medications, and blood pressure pills.

5. You’re obese. Obesity is one of the most common causes of infertility. Women who are obese may experience irregular menstrual cycles and, in some cases, their periods may stop completely. Losing weight may restart or regulate your cycles.

6. You’re underweight. With obesity, too much fat throws off the normal hormonal balance in the body. When a woman is underweight, the lack of fat can throw her reproductive cycle off. If this is the problem, bringing your weight up should restart your cycles.

7. You’re an athlete. You may be an athlete with a weight considered to be “normal.” However, it’s not your weight that really impacts your reproductive cycle—it’s the amount of fat. Athletes may have a high percentage of muscle and a low percentage of body fat. This can cause their menstrual cycles to be irregular or even stop completely.  Excessive exercise can also cause your periods to become irregular or stop.

8. You’re under high levels of stress. Stress can cause you to skip a period or two. However, it’s highly unusual for stress alone to cause your menstrual cycle to stop for months.

9. You have PCOS. Polycystic ovarian syndrome (PCOS) is a common cause of female infertility. One of the primary symptoms is irregular or absent periods.

10. You have primary ovarian insufficiency. Also known as premature ovarian failure, primary ovarian insufficiency (POI) can cause a woman to have irregular or absent periods. Sometimes, a woman with POI will go months or even years without a period, only to have them restart without explanation. POI used to be also called “early menopause,” but after menopause, menstruation never returns.

11. You have some other hormonal imbalance. PCOS and POI are only two possible conditions that can cause ovulation problems. Some other conditions that can lead to irregular or a lack of periods include a thyroid imbalance, endometriosis, an underlying untreated medical condition (like diabetes), and hyperprolactinemia.

12. There is a structural problem with your uterus. Scarring of the uterus can cause your periods to be irregular or stop completely. This may occur after a D&C or uterine surgery.

13. You’re entering menopause. This is sometimes the first fear women have when they suddenly stop getting their period, even if they are years and years away from it becoming a reality. While early menopause is possible, unless you are 45 years or older, it’s unlikely menopause is the cause for your lack of periods.

If You Want to Get Pregnant But Aren’t Having Periods

Doctors usually recommend trying to conceive for one year (or six months, if you’re age 35 or older) before getting a fertility evaluation. However, this doesn’t apply if you have signs or symptoms of a fertility problem.

If you’re not getting your periods, you may be dealing with infertility. Make sure that you and your partner are evaluated. There may be more than one reason you aren’t conceiving, and male infertility is more common than you may realize. Depending on why you aren’t ovulating, and if there are other fertility problems, treatment possibilities include lifestyle change, weight loss or gain, medication change, treatment of an underlying medical condition, or fertility treatments.

If You Do NOT Want to Get Pregnant

If you don’t want to get pregnant, you shouldn’t rely on your lack of menstrual cycles as birth control. This is true even if you’ve been previously diagnosed as infertile (unless your doctor tells you otherwise).

As mentioned above, depending on why you’re not getting your periods, it’s possible to ovulate and not get a period first as a “warning” that you’re fertile again. Talk to your doctor about the best contraceptive choice for you.

Sources:

Amenorrhea: Diseases and Conditions. www.mayoclinic.org/diseases-conditions/amenorrhea/basics/causes/con-20031561 .

Nelson LM. Primary Ovarian Insufficiency. The New England Journal of Medicine. 2009;360(6):606-614. doi:10.1056/NEJMcp0808697.

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