If your period shows up like clockwork each month, being even a few days late can make you jump to conclusions. These are the most common reasons for a missed period.
It’s easy to assume you’re pregnant when you realize your period is late. If you’re trying to conceive, you may feel excitement and a sense of disbelief. If you’re not, you might feel fear or disappointment, not to mention utter confusion if you know there’s no way you could be pregnant.
The truth is, although many women assume they’re pregnant if they miss a period, there are plenty of other things that can cause them to be late. Here are the 11 most common reasons for a missed period:
Sometimes a late period means exactly what you think: You’re pregnant! Because the early symptoms of pregnancy — like cramping, bloating, nausea, spotting, fatigue, breast tenderness and even aversion to certain foods — are similar to what you may experience in the days before menstruation, it can be difficult to tell if your cycle is simply off by a few days or you’re pregnant.
The fastest and easiest way to find out if pregnancy is the cause of your missed period is to take an at-home pregnancy test. These tests detect human chorionic gonadotropin (better known as hCG, the hormone released during pregnancy) in your urine. These tests are most reliable the day after your missed period, but some tests can detect a pregnancy up to five days before you’ve missed your period.
You already know that stress can trigger a number of unpleasant side effects, like headaches, weight gain and acne — and it can also affect your menstrual cycle. When you’re under physical or emotional stress, your body produces the stress hormones adrenaline and cortisol. Elevated levels force the brain to decide which bodily functions are essential and which are nonessential until the anxiety-inducing event is over.
While blood flow to the muscles and oxygen to the lungs will increase (part of the “fight-or-flight” response you’ve likely heard of), while others bodily functions, like digestion and those in the reproductive system, may stop temporarily in extreme cases. When the reproductive cycle is delayed, so is your period.
Think back to the time you should have ovulated. If you were sick, whether with a simple cold or something more serious, the stress could have put your body into that “which-function-is-most-important” phase mentioned above. So ovulation could happen later than usual or might not appear at all — meaning, your period will also be late or nonexistent. If illness around the time of ovulation is what caused you to be irregular, Aunt Flo’ will likely return once things are back to normal.
Your weight can affect your hypothalamus, a gland in your brain responsible for regulating various processes in the body — including your menstrual cycle. Extreme weight loss, a low caloric intake or being very underweight stresses the hypothalamus, and your body won’t release the estrogen needed to build the lining of the uterus. The same happens with eating disorders like bulimia and anorexia, which also cause estrogen levels to dip too low.
On the other hand, being overweight or gaining a lot in a short amount of time can cause your body to produce too much estrogen. The overload may cause you to go for months without ovulating or cause the endometrial lining to overgrow and become unstable, resulting in heavy, irregular or missed periods. Usually, gaining weight if you’re underweight or losing if you’re overweight should help your periods to return to normal.
Of course working out is good for you. However, when you overdo it (and possibly also restrict meals to lose weight), your body doesn’t produce enough estrogen to complete the menstrual cycle. Some women — such as ballet dancers, gymnasts and professional athletes — are at greater risk for amenorrhea (missing a period for three or more months in a row). But you don’t have to be a pro for exercise to mess with your system. Working out excessively without taking in enough calories can also cause disruptions.
Some signs that you’re overdoing it include extreme or rapid weight loss; decreased physical performance; or forcing yourself to work out through injury, illness or severe weather. Slowing down a bit and gaining a little weight if needed should get things back on track.
Change in schedule
Believe it or not, switching things up — for instance, working the night shift instead of the day, or travelling across the country — can throw off your internal body clock, which regulates your hormones. Sometimes this results in a missed or late period, but it should return when your body gets used to the change or your schedule goes back to normal.
If you’re breastfeeding, you may not see your period for some time, since prolactin — the hormone responsible for breast milk production — also suppresses ovulation. Many moms don’t have a period for months (or at all) while breastfeeding. But a lapse in your cycle doesn’t mean you can’t get pregnant. Remember, ovulation occurs before you get your period. It’s possible for you to ovulate and then get pregnant before you ever see your period. So if you don’t want back-to-back babies, use protection. Your period should return within about six to eight weeks after weaning your child. If you haven’t gotten it three months after you stop breastfeeding, talk to your doctor.
Probably the most common medication to cause menstrual changes is birth control. Hormonal contraceptives such as the pill or patch work by stopping the body from ovulating — and no ovulation means no period. But what about that monthly bleeding you have while using one of these methods? What you’re really experiencing is withdrawal bleeding, a “fake” period caused by the drop in hormones when you take the placebo pills in your pack or go patch-free during the fourth week of your cycle. Sometimes, though, the birth control suppresses the hormones so much that you have very light bleeding or no period at all during that week off. And some pills are even designed to stop your period for a longer amount of time (three months or more). Other hormonal birth controls, such as the Depo-Provera shot or the Mirena IUD, thin the lining of the uterus to such a degree that there may be no lining to shed monthly.
Emergency contraception, or the “morning after pill,” can also affect when or if you ovulate, so if you’ve taken it recently you may experience a late or skipped period (bring this up with your doctor).
Some other medications that can cause you to be irregular are antidepressants, some antipsychotics, corticosteroids and chemotherapy drugs.
If you’ve recently gone off the pill in the hopes of getting pregnant, you may notice that it takes a month or so for your cycle to regulate itself — in which case a skipped period might just be your system getting back on track. If you’re not sure whether it means you’re expecting, visit your doctor.
Polycystic ovarian syndrome (PCOS) is a condition where the female sex hormones are out of balance. It can cause cysts on the ovaries and prevent ovulation from occurring regularly. In addition to missed or irregular periods, PCOS can also cause excess hair growth, acne, weight gain and possibly infertility. Your doctor can do a blood test to check your hormone levels if you think PCOS may be the reason for your menstruation problems. If PCOS is the cause, your doctor may recommend birth control to regulate your periods.
When the thyroid, the gland responsible for your body’s metabolism, doesn’t function properly, it can cause abnormal menstrual changes. An overactive thyroid (hyperthyroidism) can cause periods to be lighter and less frequent; additional symptoms include weight loss, rapid heartbeat, increased sweating and trouble sleeping. An underactive thyroid (hypothyroidism) may also cause periods to be less frequent but heavier; it may also cause weight gain, fatigue, dry skin and hair loss. A blood test can help your doctor determine if you have a thyroid disorder.
The average age of menopause is 51. Anywhere from two to eight years before that, a woman experiences what’s known as perimenopause, the period when the body gradually makes less estrogen and moves toward menopause. During this time, it’s not uncommon to have changes in the menstrual cycle — periods may come more or less frequently, be shorter or longer, or be lighter or heavier. But you’ll also likely experience hot flashes and night sweats, sleeping difficulties, vaginal dryness and mood swings. If you’re concerned about your symptoms, your doctor can check your hormone levels with a blood test.
Though a missed period can be emotional, try not to jump to conclusions until you find out what’s really going on. A visit to your doctor can help pinpoint the cause, and if you’re not pregnant, coax your next period along and get things back to normal.