1. Flo - ovulation calendar, period tracker, and pregnancy app
  2. Your cycle

24 Top Questions About Your Menstrual Cycle Answered

Periods are characterized by bleeding from your uterus through your vagina and indicate the end of your reproductive cycle. While this is a normal occurrence in females who have started and gone through puberty, there are still some questions surrounding this phenomenon.

Kate Shkodzik, medical consultant at Flo

The medical specialist at Flo, Kate Shkodzik, answers the most commonly asked questions on periods.

Why do women have periods every month?

Period or menstruation is a monthly bleeding from the uterus and is a part of a healthy woman's menstrual cycle. All hormonal changes and changes in the ovaries and uterus that happen during a menstrual cycle are aimed at achieving pregnancy. When pregnancy doesn't occur, the uterus sheds its inner lining with blood and mucus through the cervix and vagina due to hormonal changes.  

How many months without a period is normal?

Normal menstrual cycle length is about 21-35 days. The period is considered missed if you don`t have it for more than 6 weeks. 

Sometimes period delay can be due to stress or rapid weight loss. 

Sometimes it may be a sign of an endocrine problem like polycystic ovary syndrome, thyroid dysfunction, hyperprolactinemia or some other health problem. If your periods are late, take a pregnancy test and don't hesitate to visit your doctor.

Is it normal to have periods twice a month?

It is normal to have periods twice a month only in case your menstrual cycle is about 21 days long and you have periods twice during one calendar month. However, if you have bleeding twice or more during one menstrual cycle, notice blood after sex or if your periods stopped and then started again after several days, something is wrong. 

There may be some underlying reasons for that like hormonal imbalance, ovarian cysts, endometriosis, uterine fibroids, pelvic inflammatory disease or even cervical neoplasia. If you notice bloody discharge at a time other than the time of your periods, you should visit your doctor to find out the reason for that.

When is a menstrual cycle too short?

The length of the menstrual cycle is the number of days between the first day of one period and the first day of the next period. In most women, it is about 28 days. The length of the cycle between 21 to 35 days is considered to be normal.

The menstrual cycle is too short if your menstruation starts 21 or even fewer days after the onset of your previous period. 

What can be the reasons for period delay?

There is a great variety of reasons for your periods to be late. If you are trying to conceive or for some other reason had unprotected intercourse, pregnancy is the most likely reason. If pregnancy is reasonably excluded, late periods can be caused by medical conditions: PCOS, ovarian cyst, high level of prolactin or thyroid issues. 

Sometimes using hormonal birth control methods can also cause late periods.

What causes irregular periods?

There is a great variety of reasons for periods to be irregular. The most likely is excessive stress, extreme exercising, and sudden loss of body weight or obesity. The reasons for irregular periods can also be gynecological, like polycystic ovary syndrome or functional ovarian cysts or endocrine like high levels of prolactin or thyroid issues.

Do irregular periods influence the ability to get pregnant?

Irregular periods can influence the ability to get pregnant. The reasons for irregular periods can be stress, body weight fluctuations, polycystic ovary syndrome, hyperprolactinemia, hyper- or hypofunction of the thyroid gland. Irregular periods are usually associated with problems with ovulation which may influence the ability to get pregnant. 

How long can I have irregular periods after a miscarriage?

It usually takes 4 to 6 weeks for your periods to start after a miscarriage in case you had a regular cycle before. Sometimes it can take up to three months for your period to become regular. 

One of the reasons for irregular periods after a miscarriage is stress.

Try to relax, have more rest, keep a healthy diet, exercise regularly if you used to. If your menstrual cycle doesn't become regular for three months after the miscarriage, contact your doctor to find out the reason.

Should I worry if my period is late for 1 day?

There is usually nothing to worry about if your period is late for 1 day. If you are trying to conceive or for some other reason had unprotected intercourse, pregnancy is the most likely reason. Take a pregnancy test to confirm or exclude it.

Period is 10 days late. Am I pregnant?

There is a variety of reasons for late periods. If you are trying to conceive or for some other reason had unprotected intercourse, pregnancy is the most likely reason. To confirm or exclude pregnancy, you can take a home pregnancy test which detects the presence of hCG or "pregnancy hormone" in your urine. You can also do a blood test which will also show this hormone and its quantity in blood.

I had no sex. Why can my periods be late?

There is a great variety of reasons for your periods to be late. The most likely is excessive stress, extreme exercising, fluctuations in body weight. The reasons for late periods can also be gynecological, like polycystic ovary syndrome or functional ovarian cysts.

The reasons can also be endocrine in nature like high levels of prolactin or thyroid issues (its hyper- or hypofunction). Sometimes using hormonal birth control methods can also cause late periods.

Can adaptation to new birth control pills cause the period delay?

Adaptation to new birth control pills can cause period delay. If your period is late after the first month on new contraceptive pills, take a pregnancy test. If it is negative and nothing else bothers you, you have nothing to worry about.

Can I get pregnant having sex 2 days before my period starts?

You can get pregnant on any day of the cycle. But the chances are higher during the ovulation. Ovulation is the process when the egg is released from the ovary happens usually 12 to 14 days before your next period starts. 

Taking into account that an egg lives for about 12 to 24 hours and sperms can survive for up to 5 days, the riskiest days are 5 days before ovulation and 24 hours after it. 

Is it normal to get emotional before period?

The period after ovulation and before menstruation is called the luteal phase. During this phase, your body is getting ready for pregnancy if fertilization takes place. The 'main' hormone of the luteal phase is progesterone.  

Anxiety, mood fluctuation, headache, weight gain, increased hunger are all symptoms of premenstrual syndrome (PMS). Cyclic changes in progesterone and estrogen, excess prostaglandins and fluctuations in serotonin levels are all responsible for PMS symptoms. 

About 75 percent of women suffer from recurrent symptoms of PMS. If these symptoms do not affect your everyday life, you have nothing to worry about. 

Big increase in hunger before the period. Is it normal?

Increased hunger, anxiety, mood fluctuation, headache, weight gain are all symptoms of premenstrual syndrome. PMS symptoms are the result of cyclic changes in progesterone and estrogen, excess prostaglandins and fluctuations in serotonin. 

About 3 in 4 women suffer from recurrent symptoms of PMS. If these symptoms do not affect your everyday life, you have nothing to worry about.

Why is my period blood black?

Your period can be black or dark brown at the very beginning or at the end of your period. And it is absolutely normal. At the beginning and at the end of menstruation, the flow is usually slow and blood you see on your pad or tampon is old blood.

The menstrual discharge which consists mostly of endometrium — the inner lining of the uterine wall — and blood comes from the uterus to the vagina where it is oxidized. Blood contains iron which becomes black after oxidation. However, if your menstrual blood is black during the whole period, you should contact your doctor as there can be some other reasons for that.

Can antibiotics affect your period?

The antibiotics are not responsible for the situations when women have late, early or absent periods or heavy and prolonged menstruation after taking antibiotics. The most probable cause is usually the infection for which an antibiotic was prescribed. Infections stress your body, and stress is a well-known reason for the late or absent period.  

There is a long list of side effects for the various antibiotics, but the irregular or painful period is not part of it except when it comes to rifampin. Rifampin is an antibiotic that is used to treat tuberculosis and it is the only one that is proven to cause irregular or painful menstruation.

How can I make my period come earlier?

It depends on why you need your periods to come earlier. If you need to have your period before some important occasion or going on vacation and you are already on birth control pills, you can switch to placebo pills. However, keep in mind that your period can be heavy and prolonged in case you switch to placebo pills during the first ten pills of the pack. It’s better to consult a doctor before making a switch.   

There is also a common belief that vitamin C, ginger and different herbs like parsley, turmeric and other can induce periods. However, there is no reliable scientific evidence that they work. Remember that if you have never had your period, these recommendations will not work in your case. 

Why does my period stop and then start again?

If your period came in time then stopped for up to 24 hours and then started again, it may be because old blood from the uterus didn't get expelled. In this case, this old blood may be brown or even black and the flow will not be heavy.  

However, if your period came late or early and you’re sexually active, it’s recommended to take a pregnancy test first. If it is negative and the flow is not heavy, you have nothing to worry about. On the other hand, if the pregnancy test is positive or the bleeding is heavy, you need to contact your doctor.

Bleeding after taking a morning-after pill. Is it my period?

A morning-after pill is a form of emergency contraception. It contains levonorgestrel which is a synthetic form of the hormone progesterone. A morning-after pill may cause unexpected uterine bleeding that is supposed to end before your normal period start. 

Emergency contraception pills can also cause your next period to come late or early or be heavier and more painful. The morning-after pill should not be used as a routine method of birth control.

Is it ok to feel different depending on the day of the period?

Your emotional and physical condition may differ depending on the phase of your menstrual cycle. It happens due to hormonal changes during the cycle. If these changes don't affect your everyday life and don't bring any discomfort, you have nothing to worry about.

Whom should I tell about my first period?

First period or menarche is a very important moment in every girl’s life. It is an essential stage in maturity. You may talk to your parents or close ones about your first periods. You can also ask them for help in choosing a sanitary product and discuss changes that are happening to you during this period.

What to put in a period kit?

It is a good idea to have a period kit with you during your menstruation. There should be 3 to 4 sanitary pads or tampons depending on what hygiene product you use. Remember to change pads at least every 4 hours, tampons every 4 to 8 hours, and empty and wash your menstrual cup every 10 to 12 hours. 

If you have menstrual cramps, don't forget about painkillers; non-steroidal anti-inflammatory drugs (NSAIDs) are the best option. Your period kit should also contain extra underwear in case of spotting, hand sanitizer, feminine wipes and 2 to 3 plastic bags.

Flo Period & Ovulation Tracker

4.8, 279.7K
  • Amazing! Ricecake2003
    This app is super useful for tracking periods, and has given me mostly accurate predictions so far! I especially love that you can comment anonymously on posts and get help from and give help to the community.
  • Such an intuitive app! Hannah Malone
    I've tried several period tracker apps on the market and nothing is as good as Flo. It's accurate, detailed providing you with an abundance of parameters to log, and they even provide useful articles and surveys to help you better understand the complex nature of the female body.

Track your cycle with Flo App

You will receive a one-time SMS. We will not store or use your phone number in any other way.