Understanding the phases of your cycle

At a high level, your menstrual cycle is your body’s way of preparing for pregnancy every month, or, if you’re not pregnant, you’ll usually get your period. Your menstrual cycle is controlled by various hormones, which act as chemical messengers in your body. 

Your hormones make the eggs in your ovaries mature, which means they’re ready to be fertilized by a sperm cell. Your hormones also thicken the lining of your uterus (which consists of blood and tissue, similar to the makeup of many parts of your body), making it a good environment for a fertilized egg to implant into your uterus’ lining if you were to get pregnant. You can think of your uterine lining as a cozy bed for a potential baby. If a sperm meets your egg, they’ll settle in there, but if not, that lining will leave your body through your vagina– that’s your period.

The time in your cycle, usually about halfway through, during which your ovaries release a mature egg, is called ovulation. This is the time in your cycle when you have the highest chance of getting pregnant. For some people, this phase can be accompanied with symptoms such as bloating, spotting, or cramps– reminders that your body is in action.

If pregnancy doesn’t happen (if your egg is not fertilized by a sperm), that lining of your uterus will be shed through your vagina, which is your period. If you DO get pregnant, your body needs that lining to provide nutrients to the fetus, which is why you won’t get your period during your pregnancy.

	Menstruation Period Typically from days 1-5 of your cycle, approximately The lining of your uterus sheds through your vagina if pregnancy has not occurred 3-5 days of bleeding is typical, but up to 7 may be normal
	Follicular Phase Typically lasts until day 14 of your cycle, approximately Your estrogen levels (one of the key hormones that regulates your menstrual cycle) rise, causing the lining of your uterus to thicken. Meanwhile, another hormone called the follicle-stimulating hormone will cause the follicles in your ovaries to grow. In the last several days of this phase, one of the follicles will develop into a mature egg
	Ovulation Usually happens about halfway through your cycle, about 14 days before your period starts. Ovulation refers to your ovary releasing its egg. Around the time you ovulate, you have the highest chances of getting pregnant. Ovulation may happen earlier or later for you depending on the typical length of your cycle. Your egg lives for about a day after your ovary releases it. Sperm can live in your uterus for about 6 days after sex. This means you can usually get pregnant within about a 6 day window of your menstrual cycle: the day you ovulate, or the 5 days before you ovulate. It is possible, but more unlikely, to get pregnant the day after you ovulate.
	Luteal Phase Typically lasts from about day 15 to 28 of your cycle, approximately Your egg leaves your ovary and starts traveling towards your uterus via your fallopian tubes. Your progesterone levels (another key hormone) rise to help prepare your uterine lining for pregnancy If pregnancy occurs, your egg becomes fertilized by sperm and the resulting embryo attaches itself to your uterine wall. If pregnancy does not occur, estrogen and progesterone levels drop, and the lining of your uterus will shed during your period

Irregularity and changes in your cycle

Some people have regular cycles, others’ vary from month to month. Average cycle lengths range between 25-30 days, but they may be slightly shorter or longer, and their length may vary from month to month. The length of your cycle is the amount of time between the first day of your period and the first day of your next period. Normal periods can last anywhere from 3 to 7 days. 

Missing a period is one of the first signs of pregnancy, but there are many other possible reasons for missing a period. Some things that might throw off your cycle include:

• Starting or stopping hormonal birth control (e.g., the pill, hormonal IUD, patch, implant, etc.)
• Certain medical conditions such as polycystic ovary syndrome or thyroid disorders
• Stress
• Jet lag or long distance travel
• Being sick
• Too much exercise
• Poor diet/ nutrition
• Recent or sudden weight gain or loss
• Taking certain medications
• Menopause (when your period stops for good)

As your body goes through times of change and stress, your period can also be affected. It’s especially common for younger people or people approaching menopause to have irregular periods. Irregular periods might mean an early or late period, having different symptoms or bleeding patterns than normal, or skipping your period altogether. It’s worth checking with your doctor if your periods suddenly stop or become irregular, come more often than every 21 days or less often than every 45 days, or last more than 7 days total.

Important: Data displayed are intended for informational use only. Do not use the ovulation prediction to control pregnancy or support conception. 

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