READER QUESTION: “What if I don’t have a 28-day cycle?”

My Hormonology

READER QUESTION: “What if I don’t have a 28-day cycle?”

My HormonologyKami, a Hormonology newsletter subscriber, asks: “I get my period every 20-24 days, and it only last about 4 days. How would that affect my weeks compared to a normal 28-day cycle?”

My answer:

This is a great question since most women don’t have the “perfect” 28-day cycle (myself included). Some have cycles that are shorter, some that are longer, and some women’s cycles (like yours) vary in length from month to month.

First, the length of your period doesn’t affect the length of your monthly cycle. The number of days you bleed is simply an indication of how much uterine lining you’re building up in the second half of your cycle before you shed it in the first week of your cycle. Of course, your hormones do play a key part in your period: Progesterone helps determine the amount of uterine lining you build up and plunging estrogen triggers its shedding (which is your period), but your hormone cycle itself is unaffected by the number of days you actually bleed.

Generally speaking, it’s the first half of your cycle that varies in length; the second half is typically 14 days (give or take a day and barring ill health, stress or medications that can make any part of a cycle wonky). So, if you’re healthy and have a 20-day cycle, the first half of your cycle is just 6 days. In that time, your estrogen and testosterone spike fast, shooting up quickly from rock-bottom to their peaks. Then, your Week 3 and Week 4 would be about 14 days.

Since your cycle length varies, the trick to figuring out where you are in your cycle is to know when you ovulate. This is the signal that you’re leaving the first half of your cycle and entering the second half. Luckily, there are a few easy ways to figure that out…

You can use simple tools: You can take your temperature with a “basal thermometer” first thing in the morning (when your temperature climbs .5 to 1 degree, you’re ovulating) or by using an “ovulation microscope” (spit on the lens and if you see a fern pattern when it dries, you’ll be ovulating the next day). Both of these devices are available for about $6 and $25 respectively on

You can use your body as a barometer: To figure out if you’ve passed into your Week 3, monitor your vaginal secretions. (This involves a bit of personal investigation….kind of like checking an oil dipstick for lack of a better metaphor.) When your secretions are clear and slick, you’re in the first half of your cycle. When they become cloudy and thicker, it means that progesterone is rising and your Week 3 has begun.

You can also use your moods as a barometer: Rising estrogen and testosterone in the first half of your cycle amp up your energy, outlook, talkativeness and libido. Once Week 3 hits, estrogen and testosterone take a deep plunge immediately and progesterone starts to rise. This hormonal combination makes you a bit fatigued, a little moody, perhaps blue, it makes you a bit quieter and, most notably, your once-high libido takes a steep nosedive.

All this said, please don’t use these methods to track ovulation as means of birth control. They are not foolproof and sperm is surprisingly patient, able to live up to a week inside your body, so trying to schedule intimacy around ovulation days can often be futile. Plus, you miss out on your highest testosterone days!

Anyway, above disclaimer aside, I hope this helps you understand your cycle better so you know where you are in it!

Have a question of your own? For instance, how Hormonology works, which is the best week of your cycle to do an activity or how your hormones impact you in a certain way? Ask me! Send your question to gabrielle [at] It could end up in the next Hormonology post!

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