What Is the Female Reproductive System?
The human female has a reproductive system located entirely in the pelvis. The external part of the female reproductive organs is called the vulva. Located between the legs, the vulva covers the opening to the vagina and other reproductive organs located inside the body.
The fleshy area located just above the top of the vagina is called the mons pubis. Two pairs of skin flaps called the labia surround the vaginal opening. The clitoris, a small sensory organ, is located toward the top of the vulva where the folds of the labia join. Between the labia are openings to the urethra (the tube that carries urine from the bladder to the outside of the body). Once girls become sexually mature, the outer labia and the mons pubis are covered by pubic hair.
A female's internal reproductive organs are the vagina, uterus, fallopian tubes, and ovaries. When a baby girl is born, her ovaries contain hundreds of thousands of eggs, which remain inactive until puberty begins. At puberty, the pituitary gland, located in the central part of the brain, starts making hormones that stimulate the ovaries to produce female sex hormones, including estrogen. The secretion of these hormones causes a girl to develop into a sexually mature woman.
Toward the end of puberty, girls begin to release eggs as part of a monthly period called the menstrual cycle. Approximately once a month, during ovulation, an ovary sends a tiny egg into one of the fallopian tubes. Unless the egg is fertilized by a sperm while in the fallopian tube, the egg dries up and leaves the body about 2 weeks later through the uterus. This process is called menstruation. Blood and tissues from the inner lining of the uterus combine to form the menstrual flow, which in most girls lasts from 3 to 5 days. A girl's first period is called menarche.
The vagina is muscular tube that extends from the vaginal opening to the uterus. The vagina is about 3 to 5 inches long in a grown woman. Because it has muscular walls, it can expand and contract. This ability to become wider or narrower allows the vagina to fit something as small as a tampon and as large as a baby. The vagina's muscular walls are lined with mucous membranes, which keep it protected and moist. The vagina has several functions: for sexual intercourse, as the pathway that a baby takes during childbirth, and as the route for the menstrual blood from a woman's period) to leave the body from the uterus.
A thin sheet of tissue with one or more holes in it called the hymen. It partially covers the opening of the vagina. Hymens are often different from person to person. Most women find their hymens to have stretched or torn after their first sexual experience.
The vagina connects with the uterus at the cervix. The cervix has strong, thick walls. The opening of the cervix is very small (no wider than a straw). During childbirth, the cervix opens up to allow a baby to pass. At the upper corners of the uterus are the fallopian tubes which connect the uterus to the ovaries. The ovaries are two oval-shaped organs that lie at the upper right and left of the uterus. They produce, store, and release eggs into the fallopian tubes in a process called ovulation.
If a female and male have sex, within several days of the female's ovulation (when the egg is released), fertilization can occur. Sperm "swim" up from the vagina through the cervix and uterus to meet the egg in the fallopian tube. It takes only one sperm to fertilize one egg.
The two fallopian tubes are each attached to a side of the uterus. Within each tube is a tiny passageway no wider than a sewing needle. At the other end of each fallopian tube is a fringed area that looks like a funnel. This fringed area wraps around the ovary but doesn't completely attach to it. When an egg pops out of the ovary, it enters the fallopian tube. Once the egg is in the fallopian tube, tiny hairs in the lining help push it down the narrow passageway toward the uterus.
What Does the Female Reproductive System Do?
The female reproductive system enables a woman to:
- produce eggs
- have sexual intercourse
- protect and nourish the fertilized egg until it is fully developed
- gives birth
Menstruation (a period) is a major stage of puberty in girls; it is one of the many physical signs that a girl is turning into a woman. Some girls cannot wait to start their periods, and others may feel afraid or anxious. Many girls do not have a complete understanding of a woman's reproductive system or what actually happens during the menstrual cycle, making the process seem even scarier.
Puberty and Periods
When girls begin to go through puberty (usually starting between the ages of 8 and 13), their bodies and minds change in many ways. The hormones in their bodies stimulate new physical development, such as growth and breast development. About 2 to 2 1-2 years after a girl's breasts begin to develop; she usually gets her first menstrual period.
The start of periods is known as menarche. Menarche does not happen until all the parts of a girl's reproductive system have matured and are working together.
As a girl matures and enters puberty, the pituitary gland releases hormones that stimulate the ovaries to produce other hormones called estrogen and progesterone. These hormones have many effects on a girl's body, including physical changes, growth, and emotions.
About once a month, a tiny egg leaves one of the ovaries—a process called ovulation—and travels down one of the fallopian tubes toward the uterus. In the days before ovulation, the hormone estrogen stimulates the uterus to build up its lining with extra blood and tissue, making the walls of the uterus thick and cushioned. This happens to prepare the uterus for pregnancy: If the egg is fertilized by a sperm cell, it travels to the uterus and attaches to the cushiony wall, where it slowly develops into a baby.
If the egg isn't fertilized, though—which is the case during most of a woman's monthly cycles—it does not attach to the wall of the uterus. When this happens, the uterus sheds the extra tissue lining. The blood, tissue, and unfertilized egg leave the uterus, passing through the vagina on the way out of the body. This is what we know as a menstrual period. This cycle happens almost every month for several more decades (except, of course, when a female is pregnant) until a woman reaches menopause and no longer releases eggs from her ovaries.
Why Haven't I Started My Period Yet?
Everybody goes through puberty at different speeds. Some girls begin their period as early as age 8 or 9; others do not get going until they are 15 or 16. It all depends on your hormones. When you start puberty is partly linked to genetics.
How Often Does a Girl Get Her Period?
Just as some girls begin puberty earlier or later than others, the same applies to periods. Some girls may start their period as early as age 10, but others may not start until they are 15 years old.
The amount of time between a girl's periods is called her menstrual cycle (the cycle is counted from the start of one period to the start of the next). Some girls will find that their menstrual cycle lasts 28 days, whereas others might have a 24-day cycle, a 30-day cycle, or even longer. Following menarche, menstrual cycles last 21-45 days. After a couple of years, cycles shorten to an adult length of 21-34 days.
Irregular periods are common in girls who have just started. It may take the body a while to sort out all the changes going on, so a girl may have a 28-day cycle for 2 months, then miss a month, for example. Usually, after a year or two, her cycle will become more regular.
As a girl gets older she will probably find that she can predict when her period will come. In the meantime, it is a good idea to keep track of your menstrual cycle with a calendar.
How Long and How Much?
The length of a girl's period can also vary. Some girls have periods that last just 2 or 3 days and others may have periods that last 7 days or longer. The menstrual flow—meaning how much blood comes out of the vagina—can vary widely from girl to girl, too.
Some girls may be concerned that they are losing too much blood. Though it may look like a lot, the average amount of blood is only about 2 tablespoons for an entire period. Most teens will change pads 3 to 6 times a day.
Especially when menstrual periods are new, you may be worried about your blood flow or whether your period is normal in other ways. Talk to a doctor or nurse if:
- your period lasts longer than a week
- you have to change your pad every 1-2 hours
- you go longer than 3 months between periods
- you have bleeding in between periods
- you have an unusual amount of pain before or during your period
- your periods were regular then became irregular
It can take up to 3 years from the time a girls period starts for her body to develop a regular cycle. Even then, what is regular varies from person to person. Your cycle can range from 21 to 45 days.
Changing hormone levels might make your period short one month (such as 2 or 3 days) and longer (such as 7 days) the next. You might skip a few months, get two periods almost right after each other, have a really heavy period, or one so light you almost do not notice it. (If you are sexually active and you skip a period you should call your provider ASAP).
All this irregularity can make planning for your period a real hassle. Try to keep track of when your last period started, and guess that about 4 weeks from that day you could be due for another. If you are worried about wearing that cute dress and suddenly starting your period at school, just make sure you pack protection. Carry a pad or tampon in your backpack, and wear a pantiliner to handle when it initially starts.
When it comes to periods, every girl's body has a unique (and unpredictable) timeline for getting on track. If your period still has not settled into a relatively predictable pattern after 3 years, or if you have four or five regular periods and then skip your periods for a couple of months, make an appointment with your provider to check for possible problems.
Cramps, PMS, and Pimples
Some girls may notice physical or emotional changes around the time of their periods. Menstrual cramps are pretty common—in fact, more than half of all women say they have cramps during the first few days of their periods. Doctors think that cramps are caused by prostaglandins, a chemical that causes the muscles of the uterus to cramp.
Depending on the person, menstrual cramps can be dull and achy or sharp and intense, and they can sometimes be felt in the back as well as the stomach. These cramps often become less uncomfortable and sometimes even disappear completely as a girl gets older.
Many girls and women find that over-the-counter pain medications (like Tylenol or Motrin) can relieve cramps. Also, taking a warm bath or applying a warm heating pad to the lower abdomen may decrease the discomfort. Exercising regularly throughout the monthly cycle may help lessen cramps, too. If these measures do not help, ask your doctor for advice.
Some girls and women find that their period brings about many emotional changes such as: sadness, being easily irritated, and anger. These types of emotional changes may be the result of premenstrual syndrome (PMS).
PMS is related to changes in the body's hormones. As hormone levels rise and fall during a woman's menstrual cycle, they can affect the way she feels, both emotionally and physically. Some girls, in addition to feeling more intense emotions than they usually do, notice physical changes along with their periods—some feel bloated or puffy because of water retention, others notice swollen and sore breasts, and some get headaches.
It is also not uncommon for girls to have an acne flare-up during certain times of their cycle; again, this is due to hormones. Fortunately, the pimples associated with periods tend to become less of a problem as girls get older.
Although most of the strange stuff that goes along with a girl's period is completely normal, there are a few conditions that can be more serious. If you suspect you have any of these problems listed below; see your provider for advice.
- Amenorrhea is the absence of periods. Girls who have not started their periods by the time they are 16 may have primary amenorrhea, usually caused by a hormone imbalance or developmental problem.
- Menorrhagia is the term your providers use for extremely heavy, prolonged periods. Menorrhagia is more than just 1 or 2 days of a heavier-than-average flow. Girls who have menorrhagia soak through at least a pad an hour for several hours in a row or have periods that are more than 7 days long.
- Dysmenorrhea is the medical term for very painful periods. The culprit in dysmenorrhea is prostaglandin, the same naturally occurring chemical that causes cramps. In large amounts, prostaglandin can cause nausea, vomiting, headaches, backaches, diarrhea, and severe cramps when you have your period. Fortunately, these symptoms usually only last for a day or two. Providers usually prescribe anti-inflammatory medicines to treat primary dysmenorrhea. As with cramps, exercise, hot water bottles, and birth control pills might also bring some relief.
What to Do if You Suspect a Problem
When you have questions about your period or anything else related to your development, talk to your provider. This is particularly true if you notice a change in your menstrual cycle. Though most period problems turn out to be nothing to worry about, it is always good to be safe.
See your provider if:
- You have not started your period by the time you are 16. This may indicate that you have a problem that requires medical attention.
- You stop getting your period or it becomes really irregular after it has been regular for a while (6 months or more). This can be a sign that you may have a hormone imbalance or a problem with nutrition, which can harm your body if left untreated.
- You have very heavy or long periods, especially if you have a short cycle and get your period frequently. In rare cases, lots of blood loss can cause anemia (iron deficiency) and leave you feeling really weak and tired.
- Your periods are really painful.