“The menstrual cycle is the time from the first day of a woman’s period to the day before her next period,” says Toni Belfield, a specialist in sexual health information and a trained fertility awareness teacher.

“Girls can start their periods anywhere from age 10 upwards, but the average is around 12 years,” says Belfield. “The average age for the menopause (when periods stop) in this country is 50-55.”

Between the ages of 12 and 52, a woman will have around 480 periods, or fewer if she has any pregnancies.

What Happens During the Menstrual Cycle?

To understand the menstrual cycle, it helps to know about the reproductive organs inside a woman’s body. These are:

• Two ovaries (where eggs are stored, develop and are released)
• The womb (uterus), where a fertilised egg implants, and a pregnancy grows
• The fallopian tubes, two thin tubes which connect the ovaries to the womb
• The cervix, the lower part of the womb that connects to the vagina
• The vagina, a tube of muscle connecting the cervix to the outside of the body

The menstrual cycle is controlled by hormones. In each cycle, rising levels of oestrogen cause the ovary to develop an egg and release it (ovulation). The womb lining also starts to thicken.

After ovulation, the hormone progesterone helps the womb lining grow thicker, ready for pregnancy.

The egg travels down the fallopian tubes. If pregnancy doesn’t occur, the egg is absorbed into the body. Levels of oestrogen and progesterone fall, and the womb lining comes away and leaves the body as a period (the menstrual flow).

The time from the release of the egg to the start of a period is around 10-16 days. Watch an animation about how the menstrual cycle works.

Periods

A period is made up of blood and the womb lining. The first day of a woman’s period is day one of the menstrual cycle.

“Periods last around three to seven days, and women lose about three to five tablespoons of blood in a period,” says Belfield. Some women bleed more heavily than this, but help is available if heavy periods are a problem. Find out about treatments for heavy periods.

Ovulation

Ovulation is the release of an egg from the ovaries. A woman is born with all her eggs. Once she starts her periods, one egg (occasionally two) develops and is released during each menstrual cycle.

After ovulation, the egg lives for 24 hours. “If you release more than one egg in a month, you will produce that second egg within 24 hours of the first,” says Belfield.

Pregnancy happens if a man’s sperm meet and fertilise the egg. Sperm can survive in the fallopian tubes for up to seven days after sex.

A woman can’t get pregnant if ovulation doesn’t occur. Some hormonal methods of contraception, such as the combined pill, the contraceptive patch and the contraceptive injection work by stopping ovulation.

When is the Fertile Time?

“Theoretically, there’s only a short time when women can get pregnant, and that is the time around ovulation,” says Belfield.

It’s difficult to pinpoint exactly when ovulation happens unless you’re practising fertility awareness (FPA guide to natural family planning). In most women, ovulation happens around 10-16 days before the next period.

Fertility awareness can be used to plan or avoid pregnancy, but has to be taught by a trained fertility awareness instructor. It involves monitoring vaginal secretions, taking your temperature every day, and keeping a calendar of your cycle to help pinpoint when ovulation is likely to be happening.

“It’s not accurate to say that women are fertile on day 14 of the menstrual cycle,” says Belfield. This might be true for women who have a regular, 28-day cycle, but it won’t apply to women whose cycles are shorter or longer.

Vaginal Secretions

Vaginal secretions (sometimes called vaginal discharge) change during the menstrual cycle. Around the time of ovulation they become thinner and stretchy, a bit like raw egg white.

Find out more about getting pregnant, fertility and period problems.

From www.nhs.uk

Puberty can be a confusing time because your body and your feelings are changing as you grow up. Here are answers to some of the questions that boys often ask about their bodies.

At what age do you go through puberty?

Puberty describes all the physical changes that children go through as they grow into adults. Most people start to notice changes at around 11 years old, but there’s no right or wrong time to start puberty. It might be sooner or it might be later, and this is normal.

Read more on boys and puberty.

What’s the average penis size?

Penis size varies from man to man, in the same way that everyone is a different height, weight and build. Most men’s penises are somewhere around 9cm (3.75in) long when they’re not erect, but it’s normal for them to be shorter or longer than this. Some things can make your penis temporarily smaller, such as swimming or being cold.

Most penises are roughly the same size when they’re hard, between about 15 and 18cm (6-7in) long. You can’t make your penis larger or smaller with exercises or medication. Find out more about penis size.

What is circumcision?

Circumcision is an operation to remove the piece of skin (the foreskin) that covers the tip of the penis. In the UK, it’s usually done for religious reasons, and is most common in the Jewish and Muslim communities. If you have been circumcised, it’s nothing to worry about. It won’t affect your ability to have sex.

Female genital mutilation (also called female circumcision) is illegal in the UK. It involves cutting off some or all of a girl’s external genitals, such as the labia and clitoris.

I have spots on my penis and it itches. Is this normal?

If you’ve recently had sex without using a condom you may have picked up a sexually transmitted infection (STI). Visit a sexual health or genitourinary medicine (GUM) clinic, GP, nurse, young people’s clinic or a community contraceptive clinic. Find a sexual health clinic near you.

Lots of boys have normal lumps and bumps on their penis, and spots can also be caused by an allergy or irritation. But if you’re worried, seek advice from a doctor or clinic. Medical people see problems like this every day, so there’s nothing to be embarrassed about.

Is it normal for my penis to smell fishy and have white bits behind the tip?

This can happen naturally from time to time. To prevent it happening, wash gently behind the foreskin if you have one (men who have been circumcised don’t have a foreskin) when you bath or shower. Use water, or water and a mild soap. Find out more about washing your penis.

If you’re washing carefully and the symptoms don’t go away, and you’ve had sex without a condom, you may have an STI. See a doctor, or visit a sexual health or genitourinary medicine (GUM) clinic, young people’s sexual health or a community contraceptive clinic. Find a sexual health clinic near you.

What is sperm?

Sperm is produced in the testicles (balls) and released in fluid called semen during sexual activity. Every time a man ejaculates (comes) he can produce more than 100 million sperm. But it only takes one sperm to get a girl pregnant, and that can happen before the boy ejaculates. This is because the fluid that comes out of the tip of his penis before he ejaculates (called pre-ejaculatory fluid) can contain sperm.

If you’re having sex with a girl, always use contraception and condoms to prevent both pregnancy and STIs. Talk to your partner about what contraception she’s using, and make sure that you use condoms too.

If you’re having sex with a boy, always use condoms to stop yourself getting an STI or passing one on.

Is it normal to get an erection when you wake up in the morning?

Yes, most boys have an erection when they wake up in the morning, and they can get one when they’re not expecting it during the day, even when they’re not sexually excited. This is a normal part of sexual development and growing up.

Is it normal for one testicle to hang lower than the other?

Yes, this is normal and nothing to worry about. One theory is that it stops your testicles banging together when you run.

How do I know if I have testicular cancer?

Check your testicles every month by gently rolling them, one at a time, between your thumb and fingers to feel for any unusual lumps or bumps. You’ll feel a hard ridge on the upper back of each ball. This is the epididymis, where sperm is stored, and it’s normal to feel it here.

If you feel any lumps, it probably isn’t testicular cancer, but get it checked by a doctor. Other warning signs include:

• one ball growing larger or heavier than the other
• an ache in your balls
• bleeding from your penis

If you notice any of these, see your doctor. If caught early, testicular cancer can usually be treated successfully.

What is premature ejaculation?

This is when a boy or man ejaculates (comes) too quickly during sex. This is fairly common, especially among younger men, and can be due to nerves or over-excitement. Some people don’t worry about it, and some find that using a condom can help to delay ejaculation. Find out more about premature ejaculation.

If it bothers you, see your local doctor, nurse, or visit a sexual health or genitourinary medicine (GUM) clinic, young people’s clinic or community contraceptive clinic. These places will give you free and confidential advice whatever your age, even if you’re under 16. Find a GP or sexual health clinic near you.

Can you pee while having sex?

No. During sex, a valve shuts the outlet tube from your bladder so that only sperm can pass through the tube (urethra), which you use to pee.

Why is it harder to ejaculate when you have sex a second time soon after the first?

If you have sex a second time straight after the first, it can take longer for you to reach orgasm (come). This is normal. If you’re worried about this, take a longer break after sex before you start again. Whether it’s the first, second or tenth time you’ve had sex that day, always use a new condom to protect against pregnancy and STIs.

At what age do you go through puberty?

You’ll probably start to notice changes from age 10 upwards, but there’s no right or wrong time to start. Some people go through puberty later than others. This is normal. If you have no signs of puberty by the age of 16, see a doctor for a check-up.

Find out more about girls and puberty.

Is discharge from the vagina normal?

Yes, this is perfectly normal. Girls start to produce more vaginal discharge (fluid) as they go through puberty and the hormones in the glands of the vagina and cervix (neck of the womb) begin to work. The fluid helps to keep the vaginal area moist, and protects it from damage or infection.

Before puberty, most girls have very little discharge. After puberty, what’s normal for one girl won’t be normal for another. Some produce a lot of fluid and some produce very little.

When you start your periods, you’ll probably notice that your discharge varies at different times during your menstrual cycle. It might be colourless or creamy white in colour, and it may become more sticky and increase in quantity. Find out about periods and the menstrual cycle.

My discharge smells. Is that normal?

It’s not normal if the discharge becomes smelly or green, or if your vaginal area is itchy or sore. These may mean that you have an infection, such as thrush, which is common but easily treated. If you’ve had sex without using a condom, there’s a risk you might have a sexually transmitted infection (STI).

If your discharge is different from what’s normal for you, see a doctor or nurse. Advice is free and confidential, even if you’re under 16.

Read how to keep your vagina clean and healthy.

When should you start your periods?

Girls usually start their periods between the ages of 10 and 16. Most girls start when they’re around 12. As everyone develops at different rates, there’s no right or wrong age for a girl to start. Your periods will start when your body is ready, and there’s nothing you can do to make them start sooner or later.

If you haven’t started your periods by the time you’re 16, visit your doctor for a check-up.

What should you use when your periods start?

To be prepared for your first period, keep sanitary pads (sometimes called sanitary towels) or tampons at home, and carry some in your bag.

Sanitary pads line your underwear to soak up the blood as it leaves your vagina. Tampons are inserted inside the vagina to soak up the blood before it leaves the vagina. Tampons have a string that hangs outside the vagina, and you pull this to remove the tampon.

Don’t flush sanitary pads or tampons down the toilet. Wrap them in paper and put them in the bin. Most women’s toilets have special bins for sanitary products.

There are different kinds of pads and tampons for light, medium and heavy blood flow. Use whatever you find most comfortable. Try different kinds until you find one that suits you. You might need to use different kinds at various points during your period. You need to change your pad or tampon several times a day.

You’ll find instructions in the packet on how to use them. Sanitary pads and tampons are available in pharmacies, supermarkets, and some newsagents and petrol stations.

There’s a life-threatening infection called Toxic Shock Syndrome (TSS), which affects around 20 people in the UK (men and women) every year. It’s not known why, but a lot of these cases occur in women who are wearing tampons, particularly highly absorbent (‘heavy’) ones. Find out more about TSS.

If you’re worried about anything to do with periods or want more information, talk to an older woman, such as your mum, big sister, the school nurse or a teacher. Your doctor or local contraception or young people’s clinic can also help. Find sexual health services near you.

Is my period normal?

Don’t worry if your periods aren’t the same as your friends’ periods. Every girl is different. Bleeding can last up to eight days, although it usually lasts about five days. The bleeding is heaviest during the first two days.

During your period, your blood flow may seem heavy, but the actual amount of blood is equivalent to between five and 12 teaspoons. However, you may have periods that are heavier than normal. This is known as menorrhagia, and there’s medication to treat it, so talk to your doctor if you’re worried. Find out more about heavy periods. You can also take the heavy periods self-assessment to see if your periods are heavy.

The average length of the menstrual cycle (from the first day of your period until the day before your next period) is 28 days, although anywhere between 24 and 35 days is common.

Your hormone cycle may affect you physically and emotionally. Some women don’t have any symptoms, but on the days leading up to your period you may have symptoms of premenstrual syndrome. These include:

• Headaches
• Bloating
• Irritability
• Backache
• Feeling depressed
• A general feeling of being upset or emotional
• Difficulty sleeping
• Difficulty concentrating
• Breast tenderness
• Some weight gain (up to 1kg)

Once your period has started, these symptoms usually improve. When your period has ended they disappear.

Periods can sometimes be painful. The precise cause of painful periods is unknown, but you may feel pain in your abdomen, back or vagina. It usually starts shortly before your period begins, and lasts for a few days. Painkillers can help. Find out more about treating painful periods.

What if my period is late?

If you’re worried about your period, visit your doctor or a local community contraceptive or young persons clinic (call the sexual health helpline on 0300 123 7123 for details). Girls’ periods can be irregular for many different reasons, including stress.

Another reason for a late period is pregnancy. If you’ve had sex without using contraception and your period is late, take a pregnancy test as soon as possible. You can get a test kit from your local doctor, contraceptive clinic or young person’s clinic. Find sexual health services near you. You can also do a pregnancy test yourself, using a test kit bought at a pharmacy or supermarket.

Are my breasts too small?

No. Every woman is different and everyone’s body develops at its own rate. Don’t worry about what size is ‘normal’.

How do I know if I have breast cancer?

It’s unusual for teenagers to get breast cancer. Lumps, bumps and changes to the breast are common, and most of them are benign (non-cancerous).

There’s no set method of checking your breasts, but get to know what they look and feel like so that you’ll notice any changes. However, it’s normal for your breasts to change in size or become more tender during your menstrual cycle.

When must I have a cervical screening test?

A cervical screening test (sometimes called a smear) is a test where cells are taken from a woman’s cervix (located above the vagina) to check for changes that could lead to cervical cancer. Cervical cancer can be prevented if it’s detected early through cervical screening.

In England, cervical screening tests are offered to women from age 25 upwards, every three to five years. You should have them whether you’re straight, gay or bisexual. Women who have sex with women need to have cervical screening as well as women who have sex with men.

What is the hymen?

The hymen is a very thin piece of skin that stretches across the vagina, just inside the woman’s body. Every girl is born with a hymen, but it can break when using tampons, playing sport, or doing other activities, including having sex.

Do you put on weight when you’re on the Pill?

No, there’s no evidence that the contraceptive pill causes weight gain. Some girls and women put on weight while they’re taking the Pill, but so do girls and women who aren’t taking it.

If you’ve got any questions about the Pill or any other methods of contraception, such as the injection, implant or patch, go to a GP, local contraceptive clinic or young person’s service (call 0800 567 123). Find sexual health services near you.

You can get free and confidential advice about sex, contraception and abortion even if you’re under 16.

Can you get pregnant if you have sex during your period?

Yes. A girl can get pregnant if she has sex with a boy, at any time during her menstrual cycle, and can get pregnant the first time she has sex.

That’s why you should always use contraception. There are lots of different methods, including:

• Contraceptive cap
• Combined pill
• Condoms
• Contraceptive implant
• Contraceptive injection
• Contraceptive patch
• Diaphragms
• Female condoms
• Intrauterine device (IUD)
• Mirena (intrauterine system or IUS)
• Natural family planning
• Progestogen-only pill (mini-pill)
• Vaginal ring

Only condoms help to protect you against STIs and pregnancy, so use condoms as well as your chosen method of contraception every time you have sex.

What is the clitoris?

The clitoris is a small soft bump in front of the entrance to the vagina. It’s very sensitive, and touching and stimulating it can give strong feelings of sexual pleasure. This is how most girls masturbate. Most girls and women need the clitoris to be stimulated in order to have an orgasm during sex.

Find out 15 things you should know about sex.

From www.nhs.uk