How long does your first period last? Here’s what to expect

When you’re expecting your first period, educating yourself on what’s about to go down is a great way to relieve pre-period stress. One of the biggest questions you might have is: How long does a first period last?! Is it going to be forever? Don’t panic! It won’t a We talked to Dr. Mary Jane Minkin, MD about what happens down there when you get your first period and how that determines how long your first menstrual cycle may last.

Dr. Minkin is a clinical professor in the Department of Obstetrics, Gynecology, and Reproductive Sciences at the Yale University School of Medicine. She is board-certified in obstetrics and gynecology, and practices at Yale-New Haven Hospital. Dr. Minkin also runs her website and blog, Madame Ovary, in hopes of educating women and physicians on important women’s health issues.

We asked Dr. Minkin how long a first period usually lasts. She said that the length usually varies from person to person. But the first few periods “are likely to be erratic in both timing and flow characteristics.” She further explained:

"The beginning of periods marks the waking up of ovarian function — however, what usually happens is that although the ovaries are now making estrogen, which causes the growth of the lining of the uterus, the ovaries don't usually start ovulating (ripening an egg) immediately. In some young women that happens, but most of the time the first few periods are what we call 'anovulatory' — no egg released, just estrogen activity causing the lining of the uterus to grow and be shed."

It’s ovulation that creates regularity. So, while your body prepares to begin the ovulation process, your first few periods might fluctuate in flow and length, and may not necessarily predict how your future periods will behave. The American Congress of Obstetricians and Gynecologists (AGOG) reports that the first period can last anywhere from 2 to 7 days.

Because the ovulation process takes some time to kick in, young people often don’t experience menstrual cramping during early periods — lucky! However, it’s not unusual to experience slight cramping, and Dr. Minkin said that taking Motrin or Aleve for cramps is perfectly fine.

Dr. Minkin also added that girls can expect to begin their period when they weigh around 98 pounds. She notes that because both children and adults are gaining more weight in general these days, doctors have noticed that periods starting earlier than they did in the past.

It’s now more normal to see nine- or 10-year-old getting their period if they’re around 98 pounds. But depending on your weight, your first period might not pop up until you’re 12 or 14.

We then asked Dr. Minkin if she has any advice for those about to enter menstruating age. Her best advice is to not worry about the process.

"Always be prepared," she wrote. "School nurses are usually quite helpful if something unexpected happens in school. And if there are any problems, tell Mom (or the school nurse if you aren't comfortable discussing with Mom) and she can arrange for you to check in with your health care provider (nurse practitioner, pediatrician, etc.)."

Know what to expect, carry a pad with you, and you’ll be good to go. If you have any questions at all, don’t hesitate to ask your school nurse, mom, or doctor.

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