When a penis enters a vagina during sexual intercourse, it is possible for conception to occur, resulting in pregnancy. This is the case even if:
- the girl has not had her first period (menstruation)
- the boy withdraws his penis from her vagina before ejaculating
- the girl is having her period
- it is the first time she has had sexual intercourse.
Missed periods
The first sign that a girl may be pregnant is when her period doesn’t come when expected. If this occurs, it is vital to talk to a trusted adult and/or see a doctor as soon as possible.
Contraception (birth control)
Obviously the most effective means of preventing an unplanned pregnancy is to abstain from sexual intercourse. However, for those who choose otherwise the safest and surest way is to use contraception. Some forms of contraception such as condoms also protect against sexually transmitted infections (STIs). Planning to become sexually active is a major decision that should be discussed with parents or another trusted adult before having sex.
If two people decide to have sex, it is important for both partners to talk about contraception options and to consistently use contraception whenever having sex. The responsibility for contraception should be shared equally.
There are many different types of contraception and it can be confusing deciding which method is right. No contraceptive method can be 100% guaranteed so it is important to be informed about the range of contraception available and to weigh up the risks and benefits of each. School nurses and doctors can provide information about these issues and options.
The most common contraceptive option for boys and men are condoms, which help prevent both unplanned pregnancy and STIs.
Common contraceptive options for girls and women also include condoms and:
- a contraceptive pill, which must be taken at the same time every day
- Implanon®, a small plastic rod implanted under the skin of the arm that slowly releases hormones.
The human body is sophisticated, and geared towards reproduction, so contraception must be used as advised in order to be effective.
Read more about contraception on the Get the Facts website (external site).
Conception (becoming pregnant)
Around 14 days before a girl’s period is due, her ovaries release at least one egg. This stage of the menstrual cycle is called ovulation. Ovulation is the optimum time for a pregnancy to occur if a male and female have unprotected penis-to-vagina intercourse.
When a man ejaculates (comes, reaches climax, orgasms) inside a woman’s vagina, about one teaspoon of semen – containing millions of sperm – is released into the vagina. The sperm swim into the uterus and fallopian tubes. If just one sperm implants itself into the released egg, fertilisation occurs. If the fertilised egg implants in the wall of the uterus, conception occurs and a new human life begins.
These are the ideal conditions for conception to occur, however, it is also possible to fall pregnant even if:
- sex occurs at any other time in the menstrual cycle
- the male man does not ejaculate. Conception is still possible because sperm are also present in the clear fluid released from the penis prior to ejaculation (pre-cum)
- any semen, including pre-cum, is deposited in or just outside the vagina
- the woman does not orgasm during intercourse.
Being pregnant
How would you know if you are pregnant?
An egg successfully fertilised by a sperm will remain in the lining of the uterus so that, rather than being shed, the lining stays intact to be able to nourish the egg. This means the girl will not get her usual period. A missed period can be the first sign of pregnancy. A pregnancy dates from the time of the last period, so a girl could be 4, 5, 6 or more weeks pregnant before realising it. In addition, the other physical symptoms of pregnancy (such as fatigue, nausea and breast tenderness) might not be experienced until later.
For more information see How do I know if I am pregnant?
Decisions about pregnancy
Making the decision to get pregnant is massively important. An unplanned pregnancy places enormous pressure on all those involved. If someone discovers they are unexpectedly pregnant, it is critical to seek help as quickly as possible. They need to talk to people close to them and/or health professionals who can advise them of the full range of options, considerations and choices.
What happens during a pregnancy?
It takes 40 weeks (9 months) for a baby to be ready to leave its mother’s womb (uterus). During this time it remains in the uterus, protected by a watery sac and nourished by the placenta. In the first 8 weeks the baby is called an embryo and, after that, it is called a foetus.
The placenta is attached to the inner wall of the uterus and to the foetus by the umbilical cord. It develops and grows with the baby and provides total nourishment and all the oxygen the foetus needs through the cord. The umbilical cord also removes waste products from the foetus by returning them to the mother’s circulatory system, and then out through her lungs and kidneys as part of her normal body functions.
During the pregnancy, everything the mother does has a direct impact on the wellbeing of the baby so it is important that the mother eats healthy food, and does not use alcohol or drugs.
Birth
A baby is born about 40 weeks after the mother’s last period. The average newborn baby is about 45–50cm long and weighs between 3 and 4 kilograms.
When the baby is born, the doctor or midwife ties or clamps the umbilical cord, cutting it about 5cm from the baby’s tummy. The short piece left attached to the baby dries up and usually drops off within a few days. The place where it was attached heals and becomes the navel (umbilicus, or bellybutton).
Parenthood
A newborn baby is utterly helpless and dependent on those responsible for it, all day, and every day. It needs parents and carers who will love it and put its needs before their own for the long term.
See more information about having a baby and parenting.
You can also find more information about pregnancy on the Get the Facts website (external site).