How to get pregnant

How to get pregnant

When is the best time to conceive?

For a healthy woman of childbearing age to conceive a baby, ovulation must take place. During ovulation, an egg is released from the ovary of the woman and it is this egg which is fertilised by the male sperm during intercourse.

Regardless of the length of the menstrual cycle, ovulation usually occurs 14 days before the next period is due. Therefore, the most fertile time of the month for a woman who has a 28 day cycle is this mid-cycle period.

Intercourse at this time and during the three days either side of ovulation provides the ideal conditions for a pregnancy to take place.

What is the usual menstrual cycle?

The usual menstrual cycle lasts for 28 days. However, cycles can vary considerably. Some women may have regular five week cycles; others may find that the number of days can vary from month to month. Women may experience menstrual cycles of anything from 20 to 40 days.

For women who have regular periods it is straightforward to work out the most fertile time of the month. Ovulation will take place on day 14 of a 28-day cycle and the woman will remain fertile from roughly day 11 to day 17. For women with a five week cycle, ovulation is likely to take place on day 21.

The unfertilised ovum, or egg, can only survive for about 12 hours. If it is not fertilised by the male sperm within this time, it will die and will be absorbed by the cells lining the fallopian tubes.

However, male sperm can live in the female genital tract for up to 72 hours, so the very best time for a woman to have sexual intercourse if she wants to become pregnant is between day 11 and day 14 of a normal 28-day cycle.

What if I have irregular periods?

In a woman with a 28-day cycle, given the timing of ovulation and the lifespan of a male sperm, we can estimate that she is likely to become pregnant if intercourse takes place between day 8 and day 18 of her cycle. Conversely, she is unlikely to become pregnant if intercourse takes place during the first 8 days or the last 10 days of her cycle. However, this is a very inexact science

For women with irregular periods, working out the best time to get pregnant can be difficult. It is important to note that using the ‘safe period’ as a method of contraception is likely to prove very unreliable indeed for these women. The principle underlying the so-called ‘safe period’ or the rhythm method of contraception is that women have a regular menstrual cycle.

In order to work out the most fertile time or the ‘good days’ for becoming pregnant, a woman needs to have some regularity in her menstrual cycle.

A woman who has very irregular periods may need to visit her GP for further advice on the best time to conceive. Both the woman and her partner may be referred to a fertility clinic for investigation and advice, particularly if they are having serious difficulty in becoming pregnant.

Couples who are having difficulty conceiving may be advised to keep a temperature chart or use an ovulation kit. The body temperature rises very slightly (about 0.20C after ovulation). Therefore, careful monitoring of the body temperature with a special thermometer and chart will usually demonstrate if and when ovulation is occurring. A blood test for progesterone levels on Day 21 of the cycle will also help to confirm ovulation. Ovulation kits measure the levels of different hormones in the urine and can help to predict ovulation.

What other factors affect fertility?

Many factors can affect fertility. In couples who are undergoing investigation and treatment for fertility problems, all the following factors will be looked at:


Smoking is a major factor in infertility. Any couple who are hoping to conceive a healthy baby should consider giving up smoking, or should gradually reduce their intake of nicotine, before embarking on trying to become pregnant.

Maternal age:

Fertility in the woman begins to decline after the age of 30, and becomes quite marked after the age of 35, making it much more difficult for her to become pregnant. However, there is a strange phenomenon loosely referred as ‘the last fling of the ovary’ which can occur in women in their forties and is known to have resulted in many an unexpected pregnancy!

Frequency of intercourse:

The ease with which a woman becomes pregnant is usually related directly to how often she has intercourse. If sexual intercourse takes place four times a week, then live male sperm will always be present in the outer part of the female Fallopian tube waiting to be fertilised. Provided the woman is ovulating on a regular basis, one of the male sperm is certain to link up with the ovum sooner or later. On the other hand, if a couple are only having sex once a week, the exact date of ovulation may be missed for several consecutive months, or even years.

Emotional factors:

Factors such as stress, strain, overwork, tiredness, major fluctuations in weight; obesity; illness etc can all take their toll on the fertility of both partners in a relationship. In today's high-pressure Ireland, with so many couples both in demanding full-time jobs, these are very real issues to contend with.

The vast majority of fit and healthy couples who are engaging in sexual intercourse on a regular basis without contraception are likely achieve pregnancy within a year provided there are no underlying factors affecting fertility in either partner.

It is equally possible to become pregnant the first time you try!

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