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Menstrual Cycle

A woman's menstrual cycle can range from 24 to 35 days beginning on the first day of fresh red bleeding. It is divided into two phases, occurring either side of ovulation; the follicular phase and the luteal phase.

The follicular phase is of variable length from the first day of the period until ovulation and it is during this time that, under the guidance of follicle-stimulation hormone (FSH), a dominant follicle (a fluid filled sac containing an egg) develops in the ovary in preparation for ovulation. The follicles in the ovary produce oestrogen that increases to a peak prior to ovulation.

A surge of luteinising hormone (LH) is then released and approximately 24-36 hours later the egg is released (ovulation). This usually occurs 14 days before the next period. The next phase is known as the luteal phase and is fairly regular in length, usually 10-16 days. The dominant follicle remaining after the egg is released forms the corpus luteum which produces progesterone. Progesterone causes the lining of the womb (endometrium) to thicken up in anticipation of a pregnancy. If fertilisation does not occur, the corpus luteum breaks down, progesterone levels drop and the endometrium is shed as a period (day 1 of the next cycle).

Cervical Mucus

During the menstrual cycle there is variation in the type and amount of cervical secretions. By understanding these changes and correlating them with your menstrual cycle you should be able to identify your most fertile period in order to maximise your chances of conceiving.

The start of the follicular phase is the woman's period (usually 2-6 days in length). Following the period, the amount of cervical mucus is minimal for a few days and there is a dry vaginal sensation.

The amount of secretions then increases slightly so a woman may notice a sticky white/pale yellow discharge on her underwear followed by a creamy white/yellow discharge that indicates possible increased fertility.

As the fertile period begins the secretions become more watery and slippery with a very wet vaginal sensation. The most fertile cervical mucus resembles raw egg white and is clear and stretchy (it may be stretched several centimetres between your fingers). This mucus has similar qualities to semen, allowing the sperm to survive and pass through the cervix in order to be available at the time the egg is released.

Following ovulation the levels of oestrogen drop quickly (as progesterone rises) and the cervical fluid changes abruptly, leaving a dry feeling for most of the remainder of the cycle. How often to have sexual intercourse?

There is no right or wrong answer to this question. The more frequently you have unprotected sex, the better your chances of becoming pregnant. It is recommended to have sex every 2 - 3 days throughout the month. However, there are certain days during the month when you are at your most fertile and therefore having sex around this time point will improve your chances of pregnancy. It is recommended to have sex around the time of ovulation. On a 28 day cycle, ovulation usually occurs around day 14. On a 30 day cycle, ovulation is around day 16. You are recommended to have sex in the 5 days leading up to ovulation and the day of ovulation itself.

It is important not to become too focused on having sex to become pregnant. This takes the fun out of sex and can cause strain in a relationship. Sex can become a chore that needs to be done rather than an enjoyable act between two people who love each other.

Ovulation Prediction Kits

Ovulation predictor kits tests can be helpful if you are unsure that you are ovulating each month or if you are unsure what day ovulation occurs in your cycle. Ovulation tests can indicate when ovulation occurs by detecting the "LH surge" described earlier. Ovulation usually occurs in the 24 - 48 hours after this increase in hormone level. Therefore these tests indicate when you are at your most fertile. Many different types of ovulation tests are available in your local pharmacy. Ovulation tests work like pregnancy tests in that they detect hormone levels in your urine. Follow the test instructions carefully to ensure accurate results. Be aware that different brands may differ slightly with regards instructions for use. The first urine in the morning is the best sample to test as hormone levels are more concentrated first thing in the morning rather than the evening. If you cannot test the sample straight away, store the urine in a fridge and bring to room temperature before testing.

If you have just stopped using contraceptives such as the "pill", it is recommended to allow two normal menstrual cycles (two 'periods') before using an ovulation test. Otherwise your menstrual cycle may not have returned to normal and an LH surge will not be picked up. You may also get a negative result if you have used the test too late into your cycle. If you have a history of polycystic ovarian syndrome or you are taking medications to improve your fertility you may get a false positive result as women with PCOS have higher levels of LH throughout the cycle.

Regular use of ovulation tests can be expensive. If you wish to use these tests, we suggest using them for one or two months to see if you are ovulating and to get to know your cycle. If you are ovulating each month and you have an awareness of the length of your menstrual cycle we then it is probably no longer necessary to use the tests.


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Cork Fertility Centre has now been renamed Waterstone Clinic. Please click here to visit our new site