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.
In a fertile cycle menstruation follows the Peak 11-16 days later unless conception has occurred. This interval of approximately two weeks is called the “luteal” phase.
Both clinical and laboratory studies have shown that the last day of the slippery sensation is the most fertile time in the cycle. It is called the Peak of fertility because it is the day when sex is most likely to result in a pregnancy. Studies show that ovulation usually occurs within a day of the Peak. It is important to realise that the Peak isn't necessarily the day of most mucus. The slippery, lubricative sensation may last a day or two after the visible signs of mucus, which means you're still highly fertile – the sensation is the more valuable symptom.
The first indication of potential fertility will be a change from the Basic Infertile Pattern (BIP). You will feel a change in the sensation that the mucus produces at the vulva. As the days pass you'll notice that the mucus becomes thinner and clearer, and the sensation becomes wet and then slippery. Women use different words to describe this changing, developing pattern, but the mucus will always have a wet, slippery quality because of its chemical structure and composition, even when there is too little to see.
Following menstruation there will often be a number of days when you feel dry and don't see any discharge. This is called the Basic Infertile Pattern (BIP). We know from the work of scientists that the hormone levels are low at this time and the cervix is blocked by a thick plug of mucus which prevents sperm entering the uterus. This means that you're infertile at this time.