"The cervix is a precision organ as complex as the eye."

The cervix lies between the vagina and the isthmus which leads to the body of the uterus. It is 25mm long and contains several hundred crypts (glands) lined by cells which, under hormonal and neural influence, manufacture mucus, which is released into the cervical canal.

J.B. Brown D.Sc. Ph.D.

Ovulation - the release of an ovum by the ovary - is the most important event of the fertile cycle; it occurs only once at a moment in time during the cycle, even when more than one ovum is released.

You may be wondering which irregularities in your mucus pattern and your menstrual cycles should be considered abnormal. There are different kinds of ovarian activity that are completely normal responses to different times and events in your life. Your Billings Ovulation Method® chart will help you make the connection between what is going on with your mucus pattern and menstrual cycle and what is going on in your life and your body. So let's take a look at these normal "irregularities" before we look at what might be abnormal.

Ovulatory Dysfunction is the absence of ovulation or abnormal ovulation activity. This condition is a major cause of infertility. It is often associated with irregular menstrual cycles and is usually caused by hormonal disorders. Adrenal and ovarian hormone abnormalities are the most frequent cause of ovarian dysfunction, and the most common example of this is Polycystic Ovarian Syndrome (PCOS). It is estimated that 5 to 10 per cent of Australian women have PCOS, but many don't know they have it.

The lining of the uterus, called the endometrium, thickens during each menstrual cycle in response to the hormone oestrogen. Progesterone levels begin to rise around the time of ovulation, changing the endometrium to make it ready for the implantation of a fertilised egg. If conception doesn't take place, the levels of progesterone and oestrogen fall, causing the endometrial lining to be shed.

The most effective way of learning to recognise your individual pattern of fertility and infertility according to the mucus signals is to record your observations each day in a chart. The aim is to identify on any day whether intercourse could or could not result in pregnancy.