In order to get pregnant (or to reduce the risk of pregnancy if no form of contraception is being used), it is important for a woman to understand the different phases in her menstrual cycle, and what they represent physiologically.

It is relatively easy for a woman who has regular periods to monitor her menstrual cycle, and understand when she is experiencing each of the three main phases. However, if periods are irregular, these phases can be more difficult to gauge.

Menstrual cycles tend to last between 26 and 34 days, with the average being 28 days. The stages of the cycle are as follows:

Phase 1, the follicular phase.

This phase is when the lining of the womb thickens in preparation for a fertilized egg. It is also the phase when estrogen and other hormone levels rise and stimulate follicles in the ovaries. The largest of these follicles will develop and become the egg, which is then released in phase two. Menstruation occurs during the follicular stage.

Phase 2, Ovulation.

This is when an egg is released by one or both of the ovaries. The egg then travels through one of the fallopian tubes, where, after a day or two, if unfertilized, the egg will dissolve. During ovulation, it is not uncommon for some women to feel slight pain in the pelvis area, and due to hormone fluctuation, mid cycle blood-spotting can occur. Women who experience this can generally ascertain that ovulation is occurring.

Phase 3, Luteal phase.

This phase is when the ovaries continue to secrete corpus luteum, which is a thick substance that grows after the egg has been released. This substance will then line the womb, creating thick mucus, perfect for a fertilized egg to develop on.

The most fertile period of a woman's monthly cycle generally runs from five days before ovulation until one to two days after an egg has been released. This is when a woman is most likely to get pregnant.

Women with regular cycles can monitor dates using a calendar-based method, ascertaining when ovulation occurs by considering the following general guidelines.

• The start of menstruation is considered day 1 of the menstrual cycle.

• In a 28-day cycle, there is a 14-day luteal phase, which happens at the end of the cycle.

• Ovulation generally happens approx 12 days into the average menstrual cycle.

• The most fertile period of the cycle tends to be at the end of the 2nd week/at the beginning of the 3rd week, just before and immediately after ovulation.

Keeping a diary of menstruation and ovulation symptoms is an ideal way for a woman to monitor the phases of her cycle. There are books and online calendars that make this clear and easy, requiring just a small amount of data.

Other ways of monitoring the menstrual cycle include plotting basal body temperature (which lowers just prior to ovulation), and checking the consistency of cervical mucus and the position of the cervix, both of which change during certain times of the month. Home ovulation kits are also available. These are kits that indicate when ovulation is occurring by measuring hormone levels present in the urine.