How conception works

• How conception works
• How to maximise your chances of conceiving
• When to worry
• How do I know I've conceived?

How conception works

Conception is a remarkably complex process. The male has to produce a sperm and the female has to produce an egg which then have to come together at just the right time and in just the right place. If you want to give yourself the best chance of conceiving, it is essential that you understand how the male and female reproductive systems work, and what happens when.

• The female
• The male
• Conception

The female

Each month the woman produces an egg from one of her two ovaries, which lie one on each side of the uterus (womb). The ovaries are glands which store the eggs in small sacs called follicles. Once the egg is released, fine hairs at the end of one of the fallopian tubes pick it up and waft it into the fallopian tube.

The egg then travels down the fallopian tube into the uterus. If it has been fertilised, the egg implants itself into the lining of the uterus (the endometrium). During each cycle the endometrium thickens ready to receive a fertilised egg. (If there is no fertilised egg, the endometrium breaks down and is shed from the body at menstruation, when a woman has a period.)

The male

Male semen contains several million sperm, but only one will be needed for conception, and that single sperm cell contains the father’s genetic contribution to the baby. The sperm can swim, and need to be able to do so as they have to move through the cervix, into the uterus and along the fallopian tubes. As they travel, chemical changes mature the sperm so that they become capable of fertilising an egg.

Conception

When a couple has sexual intercourse with full penetration, the man ejaculates his semen into the woman’s vagina near the cervix, the entrance to the woman’s uterus. The cervix is usually blocked by cervical mucus, but this thins around the time of ovulation (when an egg is released from one of the ovaries) to allow sperm to pass through.

The sperm and egg usually meet in the fallopian tube. A single sperm penetrates and fertilises the egg, which then travels into the uterus where it implants into the uterine lining. Once it has implanted, the growing embryo is sustained by hormones, until the developing placenta can take over and nourish the pregnancy. About nine months after conception, the developing baby is ready to be born.

How to maximise your chances of conceiving

You can do a great deal to improve your chances of conception by paying attention to your health and lifestyle. These changes in your lifestyle will be useful when you are pregnant as well.

• Take good care of your health
• Keep sperm cool
• Have sex at the right time
• Checking your cervical mucus
• Checking your temperature
• Ovulation predictor kits
• Have frequent sex

Take good care of your health

• Eat a varied diet with plenty of fresh fruits and vegetables, protein-rich food such as fish, poultry or pulses, and whole grains
• Avoid smoking, or cut down if you find it impossible to give up
• Limit alcohol intake
• Take regular exercise; aim for three 20 minute sessions each week. Try walking, swimming or cycling
• Get adequate rest and relaxation. Avoid high stress levels

Keep sperm cool

Sperm develop best at a temperature 2-3°C lower than the rest of the body, which is why the testes are outside the body. Wearing tight underpants or jeans can raise the temperature of the testes and lower sperm production, so wearing boxer shorts is worth a thought.

Have sex at the right time

The best time for ‘baby-making’ sex is just before ovulation. The average length of a woman’s fertility cycle is 28 days, counting Day 1 as the first day of a period and going on to the beginning of the next. If you have a regular 28-day cycle, you can therefore predict that ovulation is likely to occur mid-cycle, on around Day 14. Many women find, however, that their cycle length varies a great deal, which makes calculating the mid point difficult.

Fortunately, there are other natural changes in a woman’s body which can help you to work out when your ‘fertile’ pre-ovulation days might be, and increase your chances of conceiving.

Checking your cervical mucus

The cells lining the cervix produce mucus continuously but its appearance changes as your hormone levels change throughout your monthly cycle.

In the early part of the cycle, the mucus is thick and sticky; it blocks the cervix, making it difficult for sperm to get through. Most women are not even aware of any mucus at this time.

As ovulation approaches, the mucus thins and becomes clear. This allows the easy passage of sperm through the cervix. After ovulation, the mucus again becomes thicker.

Observe your mucus for a month or two and you will begin to notice the difference, and be able to time intercourse for the time the mucus is thin.

Checking your temperature

After ovulation, a woman’s basal body temperature rises slightly, by around 0.2°C, and keeps at this higher level until menstruation begins. To see this rise, you need to take your temperature every morning and record it on a special chart.

‘Basal’ means ‘the temperature of the body at rest’. You therefore need to take your temperature when you wake, before going to the bathroom, having a cup of tea, or any other activity, as this can cause your temperature to climb.

Ideally you should have had sex on the days just before your temperature began to rise, so keeping temperature charts can only give you a general picture of when your most fertile time might be, and tell you whether or not you’re having intercourse near to ovulation.

Ovulation predictor kits

You can also buy ovulation predictor kits which measure the changing levels of hormones in your body to help you work out the ‘best’ time for intercourse.

Have frequent sex

Remember, too, that the more often you have sex, the more likely it is you will have intercourse on the fertile days! According to an eminent infertility expert, one of the most common causes of infertility is infrequent sex at the best time of the cycle. Your partner will not ‘run out’ of sperm. Sperm counts are slightly lower if a man has frequent sex, but since each ejaculation contains millions of sperm this will not affect his ability to produce sufficient sperm.

When to worry

• What are our chances?
• When should we go to the doctor?
• Keeping a temperature chart

What are our chances?

Pregnancy is a matter of chance. It does not always happen even if the egg and sperm are in the right place at the right time, and the length of time that it takes couples to conceive varies a great deal. Some couples will be lucky and conceive the first month; others will be still trying a year later, but that doesn’t necessarily mean there’s anything wrong.

The chances of getting pregnant in each cycle vary according to a wide range of factors, but perhaps the most important one is the woman’s age.

• For a woman aged 20-25, the chances of conceiving are around 25 per cent for each cycle (that is a one in four chance)
• For a woman aged 30-35, the chances are 15 per cent, and thereafter the likelihood of becoming pregnant continues to decline with increasing age
• It will take a couple in their early twenties an average of five cycles to conceive
• Women in their early thirties will get pregnant, on average, after nine cycles
• One in ten couples will take more than a year to succeed in conceiving

When should we go to the doctor?

Given the chances listed above, most GPs tell you not to worry until you have been having regular sexual intercourse without contraception for at least a year. Only then does it become more likely that there is a reason why you are not conceiving and this can be investigated.

However, if any of the following apply to you and your partner, you could ask your GP to arrange straightforward sperm and ovulation checks after you have been trying for six months:

• You are over 30 and feel that ‘time is running out’
• You suspect that you might be having problems with ovulation (perhaps because of very long or irregular cycles)
• If either of you has had a sexually transmitted disease
• If you have had abdominal or pelvic surgery

Keeping a temperature chart

If you are reluctant to see your GP just yet, it may be worth starting to keep a temperature chart, as this is one of the first things your doctor is likely to ask you to do if and when you do go and see him. Your GP or family planning clinic can supply charts to fill in. Ovulation predictor kits also usually come with charts to fill in.

These charts play a useful role in alerting couples that there might be a problem (for example, charts which consistently show no temperature rise can indicate that ovulation is not occurring). Also, if you do decide to seek further treatment, a series of charts may show your GP that intercourse is taking place at the right time but conception isn't.