Image of abstract cycles to represent a normal or irregular period cycle.

Menstrual cycle length: Just what’s normal? 

We frequently hear 28 days thrown around as the “normal” length of a menstrual cycle, with ovulation occuring 14 days in, but that’s not the reality for many people. A cycle might last about 28 days on average, but cycle length can vary greatly between individuals who are still considered to have regular cycles. Few people have a perfectly “normal” cycle – exactly 28 days long with ovulation and menstruation that come like clockwork.

What is a “normal” period cycle?

Really, anything between 21 and 35 is considered normal, and the length of a period varies from person to person and even cycle to cycle. For a period to be considered regular, its start date needs to vary no more than seven days from cycle to cycle. If your period starts a few days later this cycle than it did for the previous cycle, you can still consider it a regular period as long as it didn’t start more than a week later. The same principle applies if it starts earlier too. Because your cycle length and period start date can vary from cycle to cycle, the timing of ovulation will vary too, so it’s important to track!

What does this mean for how long it might take to get pregnant?

Although some individuals may experience difficulty getting pregnant, all of the long-term statistics point only to success. Even without tracking fertility data, over 50% of couples who are TTC are able to conceive within the first six months of trying, and this number rises to over 80% when the time frame is increased to a year. However, tracking your fertility data can dramatically help your odds of conceiving, with Ovia users reporting pregnancy in an average of just 56 days.

What happens if you can’t get pregnant?

Most doctors characterize a woman under 35 as infertile when she has unsuccessfully tried to conceive for at least a year. For women older than 35, most doctors recommend infertility treatment after six months. However, it is important to understand that being infertile is completely different than being sterile, and many options such IVF and fertility medications are available for those who are struggling to conceive. Ovia suggests that women seek medical advice about their fertility options after six months of unsuccessful attempts while tracking their data.

All individuals are different and all cycles are different, so the time it takes to get pregnant is different for everyone. What’s “normal” for others might not be so normal for you, and vice versa — it’s simply about finding out what activities and behaviors help your unique fertility.

Read more
  • Creinin MD, Keverline S, Meyn LA. “How regular is regular? An analysis of menstrual cycle regularity.” Contraception. 70(4):289-92. Web. 10/4/2015.
  • “Patient Fact Sheet: Infertility: An Overview.” ASRM. American Society for Reproductive Medicine, 2012. Web.
  • Mayo Clinic Staff. “Menstrual cycle: What’s normal, what’s not.” Mayo Clinic. Mayo Clinic, 4/16/2013. Web.

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