We get a lot of questions at Scarleteen from folks who are worried about periods that are MIA (missing in action, for us civilians). Sometimes there's a pregnancy concern, and sometimes not; but even if you're not sexually active, a missing period can be worrying.
Periods are hormonally related to ovulation. (The whole cycle is explained in On the Rag: A Guide to Menstruation, but we're just hitting the basics here.) When you ovulate, the released egg travels down the fallopian tube and into your uterus, where it is then shed with your menstrual lining during your period.
The usual time between ovulation and menstruation is 14 days, although this can vary tremendously from person to person.
Pregnancy. If you engage in sexual activities that can lead to pregnancy, you may have a pregnancy risk. Worried you might be pregnant or want to know how to figure out if you have a risk or not? Check this out. If you do have a pregnancy risk, no matter how small, the only way to tell if you're pregnant is to take a test, which you can do as soon as the first day of your missed period or fourteen or more days after your risk or suspected risk, whichever comes first. .
Stress. Your body looks for optimal conditions to aid conception before you ovulate. If you're stressed out around the time of ovulation, your ovulation may be delayed, throwing off your schedule and causing your period to be just as late, too.
No ovulation. It is possible that you will not ovulate regularly, or that you may not ovulate at all in a given month. If you don't ovulate, you may also not get your period, and skip a period for that month.
Coming off hormonal birth control. If you've stopped taking the pill, the patch, the shot or any other method of hormonal birth control, it can take up to six months for your periods to return or to establish a regular pattern.
Weight loss. Your body requires a certain percentage of fat in order for you to menstruate. Lack of menstruation is very common in women with anorexia or who are underweight for other reasons.
Exercise. Exercise is good for you and an important part of having a healthy body, but again, an abrupt change to strenuous exercise or a lot of exercise can disrupt your cycle. It is not uncommon for serious athletes to stop menstruating.
Age. The menstrual cycle is hormonally driven, but the rapid hormonal changes teenagers experience can mess with your body's menstrual cycle. For that reason, periods in young women are typically irregular.
When you take the combination pill, ovulation is suppressed. For 21 days, you take a pill with the correct hormone combinations to trick your body into thinking it's already ovulated. For 8 following days, you take sugar pills with no hormones. Because your body thinks you've already ovulated, this is the phase in which you're supposed to get your period, known as withdrawal bleed, when on the pill.
But, if you don't get it, here are some reasons why you might not:
Pregnancy. No method of birth control is perfect, and there is always a pregnancy risk, no matter how low, if you are engaging in the types of sex that can lead to pregnancy. Its smart to take a pregnancy test before starting your next pill pack to make sure you're not pregnant.
Low estrogen. It is not unusual with combined or low-estrogen pills to not have a period, or to have a very light one, or even one day of just a brownish discharge. You can discuss this with your healthcare practitioner if having no periods or very light, spotty periods is a concern for you. A change in your method or brand of birth control may be a good idea.
Exercise and weight loss. As with women who are not on the pill, exercise and weight loss can play a role in stopping menstruation.
Don't stress. Contrary to popular belief, stress itself won't stop you from getting your period full-stop, but it's not very useful. It's far better to do something than to worry.
Take a pregnancy test. If you have had a pregnancy risk, take a home pregnancy test. It will be accurate on the first day of your missed period.
See your healthcare provider. If you miss more than two periods, see a healthcare provider. Long-term absence of menstruation can cause related health problems (or may be caused by certain conditions which require treatment), and should be investigated.
So, if your period is late and you're not pregnant, there's no need to worry. You're in good company: thousands of periods go missing in action every month, and most of them turn up in their own sweet time.