Check out part one of our series on menarche here.
What will my first periods be like?
Getting your first period is a sign that you’ve reached the beginning of your reproductive years, when it’s possible to become pregnant. Knowing what to expect when your cycle begins can help you be less anxious. It’s also important to know the difference between what’s typical, and what you should talk to your healthcare provider about.
It’s common for your cycles to be somewhat unpredictable for about two years after your first period. This means your periods may not always come at the same time every cycle. Your periods may also look and feel somewhat different cycle-to-cycle. Your first period may be quite short, with only a little bit of bleeding and your second period may be longer with more bleeding. After a couple of years, your cycles should become more regular, but may still continue to vary. Most cycles settle into a predictable rhythm about six years after menarche (1).
It takes about six years for most cycles to settle into their regular rhythm.
Why isn’t my period “regular?”
Your reproductive hormones are still coming into balance. Each cycle, these hormones have rhythmic ups and downs. These ups and downs cause some big events — the release of an egg from your ovary (ovulation) and the growth and shedding of the lining of your uterus (menstruation). The hormones in your cycle might also cause different symptoms at different times of your cycle, like cramps and acne. They may lead you to feel extra social one day and less social a few days later. (Your reproductive hormones include estrogen, progesterone, follicle stimulating hormone, testosterone and others.)
In the years after you start menstruating, your hormones are not yet regular enough to cause ovulation to happen each cycle. Ovulation only happens in about 2 in 10 cycles during the first year of having your period. By the sixth year, ovulation happens in about 9 in 10 cycles (1-3). When you don’t ovulate, your period may come at a different time. It can look and feel differently too and your cycle symptoms will probably be different. Eventually, your hormones should come into balance. Your cycle is still likely to vary a bit after that, but not like when it first begins.
An egg is released by the ovary in only ~2 in 10 cycles during the first year. By the sixth year, this happens in about 9 in 10 cycles.
For the first two or so years after menarche, it is typical to have:
Cycles that usually last between 21 and 45 days, but may sometimes be longer or shorter
Periods that last seven days or less
Periods where you use up to ~3–5 regular pads or tampons per day (and at most 6). If you’re using a menstrual cup, this is between ~5–30ml in your cup.
Some lower abdominal cramps and/or lower back pain before or during your period (4-8)
For the first couple of years, about 9 in 10 of your cycles will be within the range of 21–45 days — the odd cycle may be shorter or longer than that (5). By your third year of menstruating, about 6–8 in 10 of your cycles will likely be within the range that is considered “normal” for adults* (6).
For the first ~two years, most cycles should be between 21–45 days long. After that, they should begin to settle into a 24–38 day range.
Talk to a healthcare provider if you have:
Cycles that consistently fall outside of the range of 21–45 days (or 24–38 if you’ve been menstruating for several years)
Periods that become very irregular after having regular cycles for at least 6 months
No period for more than 90 days
No first period by the age of 15
The growth of facial hair, unusual body hair, or thinning hair on your head
Intense pain/cramps, or pain that is not relieved by over-the-counter medication (4-8)
Your cycle = a messenger from within
Your cycle can let you know when everything is working as-usual, or if something else might be going on — this is why it’s important to track your cycles. An unpredictable cycle may be the first noticeable symptom of a treatable hormonal condition. Common conditions that sometimes show-up during the teenage years include polycystic ovary syndrome (PCOS) and endometriosis. Treating these conditions as early as possible is important.
You should aim to have a check-up with an OB/GYN between the ages of 13 and 15. An OB/GYN will ask you questions about your health and body and may perform a basic physical exam. A pelvic exam is not usually performed at your first visit. They might also ask the date of your first period and how your cycles and periods have been (bring your phone, or a Clue cycle review).
Does this mean I can get pregnant?
Yes. It’s also important to know that pregnancy is possible even if you haven’t had your first period yet. The way the cycle works means someone can be fertile before they ever get their period (9): ovulation and the growth of the uterine lining both happen in the weeks leading up to menstruation. Safe, protected sex is important, whenever you choose to have it.
It’s possible to become pregnant even if you haven’t had your first period yet.
What to track
Menarche is an exciting time to start tracking the dates of your periods, as well as any other feelings or changes you notice in your body and moods. Tracking will give you a record of your menstrual history and help you to see emerging patterns in things like mood, energy and how social you feel. This can help you learn what to expect over time and give you clues as to when you may be ovulating or are about to get your period (even if it’s irregular at first). Tracking will also help you learn to use your cycle as a vital sign to your overall health, as you learn what your own unique “normal” looks like.
Essential to track:
Helpful to to track:
Skin (if you have acne)
Any other symptoms you might be concerned about
*The typical range for adults used to be considered 21–34 days long. This range for adults is now considered 24–38 days. This article was updated on March 16, 2021 to reflect the newer range.
Learn about your body and women’s health
*Article originally published on February 17th 2017
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