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What is a period? Our 101 guide to menstruation

Aug 28, 2019 By Heather Porter
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A period — also called menstruation — is when the thick lining of a female’s uterus breaks down and exits the body, usually once a month. This lining contains blood, tissues, and nutrients, and it develops as your body’s way of preparing itself for pregnancy. If no pregnancy occurs, your hormones tell your body to shed the lining that built up over the course of the previous 28 days or so, resulting in a period that can last up to a week.

When do periods start?

Periods start during puberty, which is when your body begins to change and become more like an adult. This typically happens between 8 and 14 years old, though puberty is a gradual process that can take years. Periods usually begin around age 12 to 15 for young women, but it’s important to remember that everyone’s body is different. If you don’t receive your period by the age of 16, it is important to be evaluated by a physician to assess why there has been a delay.

Periods typically stop between the ages of 45-55, in which women enter menopause.

What are the side effects of having a period?

Up to 2 weeks before the start of your period, you might start to notice changes in your body. These symptoms, often referred to as Premenstrual Syndrome (PMS), include:

  • Abdominal cramps
  • Lower back pain
  • Headaches
  • Acne
  • Fatigue
  • Swollen or tender breasts
  • Bloating
  • Insomnia
  • Mood swings

These symptoms usually become predictable, as they recur each month around the same time.

To help with premenstrual symptoms, try:

  1. Taking over the counter pain medication like acetaminophen and ibuprofen.
  2. Regular exercise
  3. Limit fat, salt, sugar, caffeine, and alcohol.
  4. Consider starting hormonal birth control like the pill, mirena, or nexplanon.

If any of these premenstrual symptoms are severe enough to impact your daily life, see your doctor right away – they can help find ways to reduce the intensity and frequency of your symptoms. If you find your mood is sharply influenced by the onset of your period, this may be a sign of Premenstrual Dysphoric Disorder (PMDD). Your doctor can help you navigate the changes in your mental health and see if there are any steps that can be taken to reduce its negative impact on your life.

What should I know about pads, tampons, and menstrual cups?

The most common products known as “feminine hygiene products” are pads, tampons, and menstrual cups . All 3 methods help you go about your daily life by collecting the blood released during your period.

Pads are worn outside of the body, and most are disposable after a single use. The material is highly absorbent and protects your clothes against leaks. Some women prefer pads because they’re convenient and don’t require insertion into the vagina.

Tampons act as a plug against menstrual blood, absorbing it from its place inside the vagina. These usually come with an applicator for quick insertion and a string for easy removal. A lot of women choose tampons because they’re small, are rarely felt inside the body, and allow for a greater range of activity — even swimming or playing sports.

It is important to change tampons every 4-8 hours (overnight is ok) to avoid a build up of bacteria. Tampons left in longer than 8 hours increases your risk of a very rare condition called Toxic Shock Syndrome (TSS) if worn for longer than 8 hours.

Symptoms of Toxic shock syndrome are:

  • Fever
  • Nausea and vomiting
  • Diarrhea
  • Muscle and body aches
  • Sore throat
  • Dizziness or feeling weak/faint
  • A sunburn like rash

If you develop any of these symptoms, please contact your doctor immediately.

Menstrual cups are shaped like tiny bells, and — like tampons — they’re worn inside the vagina. Rather than absorbing blood like pads or tampons, menstrual cups are made of medical-grade silicone and collect the blood released during your period. They need to be emptied, washed, and reinserted into the vagina over the course of your period.

Women who use menstrual cups report that they enjoy that they’re reusable, can be worn for up to 12 hours at a time, and don’t carry any risk of Toxic Shock Syndrome.

Can I have sex while on my period?

Yes! Having sex on your period is completely safe, and the only real drawback is the mess that might develop as a result.

Can I get pregnant while on my period?

Yes. The highest risk of pregnancy is during ovulation, typically 14 days before your period. Although the risk of getting pregnant is lower on your period, it is still important to use condoms or other methods of birth control to avoid any unintended pregnancies. Check out our guide to birth control for a comparison of the various birth control methods available.

What is my period is late?

Don’t panic. It is common for periods to come a little earlier or later as not all women have their period every 28 days. A typical cycle is between 21-34 days. Activities that can affect the onset of your cycle are diet, excessive exercise, stress, medication, and several other lifestyle factors. If your period is taking longer than 35 days to occur and you are sexually active, you should take a pregnancy test even if you are on birth control. Pregnancy tests are most accurate at least 1 week after your expected period date. If you are not sexually active or your pregnancy test is negative, it may be a good idea to check in with your doctor to see if there should be any other tests you should do.

Still curious about what to expect during a period? Book an appointment today to talk with a One Medical doctor, or reach out for virtual care.

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Heather Porter

Heather Porter is a Bay Area writer and editor.

The One Medical blog is published by One Medical, an innovative primary care practice with offices in Boston, Chicago, Los Angeles, New York, Phoenix, the San Francisco Bay Area, Seattle, and Washington, DC.

Any general advice posted on our blog, website, or app is for informational purposes only and is not intended to replace or substitute for any medical or other advice. The One Medical Group entities and 1Life Healthcare, Inc. make no representations or warranties and expressly disclaim any and all liability concerning any treatment, action by, or effect on any person following the general information offered or provided within or through the blog, website, or app. If you have specific concerns or a situation arises in which you require medical advice, you should consult with an appropriately trained and qualified medical services provider.