This method is based on the recognition of changes in the cervical mucus through a woman’s menstrual cycle. It is often called the Billings method, after Drs E.L. And J.J. Billings who developed it fully.
Many women may already be aware that the mucus secreted in the vagina has different qualities at different times of the month, but may not realize that this is related to ovulation. From day one of the menstrual cycle the woman’s oestrogen level slowly builds up to a peak at ovulation; as the oestrogen level rises, the mucus secreted by the glands of the cervix changes in quality. From being scant and thick, creamy and opaque, it becomes clear, more liquid, very slippery and also stretchy. This provides an ideal medium for sperm to live in, and helps them travel easily through the cervix and on to fertilize an ovum. Gradually after ovulation, when progesterone is more dominant in the body, the mucus again becomes thick, sticky, opaque and impenetrable to sperm.
The essence of this technique is to recognize when the mucus is going through the changes which say that ovulation is imminent. The quality and quantity of the mucus can vary considerably from woman to woman and from one cycle to another, but the key factor is its stretchability. This is a quantifiable quality known as spinnbarkeit–`that which can be drawn into a thread’. The spinnbarkeit reaches a peak around the time of ovulation, when the mucus can be stretched several centimetres; the mucus at this time is often likened to raw egg-white, very slippery and glassy.
If you rely on thealone, you should avoid sex from the time that the mucus begins to show any sign of clarity, wateriness, glassiness or spinnbarkeit. This involves checking the mucus several times every day, either by wiping the vulva with a tissue or toilet paper and then examining the mucus, or by doing a digital examination. Sex should be avoided until all trace of spinnbarkeit has disappeared for several days.
Thehas one advantage over the calendar and temperature methods: it can, in some women, give warning of ovulation. This is not always the case; as Shapiro says in The Birth Control Book ovulation can occur one or two days before or after the so-called peak symptom (maximum spinnbarkeit). Without using any other methods to check when you have ovulated you will find it difficult to know which applies to you. For some women the time of ovulation can be obvious as they experience the mittelschmerz or midpain caused by congestion of the follicle when it is ready to burst. Women who don’t naturally experience the mittelschmerz can provoke it by a rather bizarre method of bouncing up and down on a hard chair several times, but I’m sure that this becomes rather tiresome!
If you are dedicated to using the mucus method to determine your fertile time, there are ways of improving or confirming your observations. One is by using a speculum and mirror for self-examination; with this device you are able to see the external os (mouth of the womb). In this way, you can check whether there is little mucus, or whether it is dribbling, trickling or virtually pouring out of the os. The greater the quantity, the closer you are to ovulation, as a general rule. Also the os itself gradually opens towards the time of ovulation, and also lifts higher in the vagina. Both of these factors can help you slightly towards predicting ovulation, although they still might not give you enough warning to avoid sex — remember that sperm can live for up to four days.
Two other ways of testing the mucus can confirm the timing of ovulation. The concentration of glucose sugar in the mucus is high at the time of ovulation. In America kits have been developed to test and indicate the glucose level; these are not available in this country, but a similar test can be made by using diabetic Tes-tape. A short length of this can be secured over the tip of the finger with an elastic band, and the fingertip touched against the os. The yellow paper will turn various shades of green/blue towards ovulation, and dark blue when ovulation is imminent or has just taken place. Most proponents of the mucus method in this country prefer to train women to recognize the natural qualities of the mucus rather than to rely on testing kits.
A further method of testing the mucus is by microscope. Mucus smears taken at the time of ovulation show a phenomenon known as lerning’ under a microscope — the specimen is made up of many branching arms like a fern. This ferning builds up to ovulation time, and disappears completely within two or three days. However, any traces of blood in the mucus negate this effect, and some women experience a very slight bleeding at the time of ovulation.
All of the methods used to check the cervical mucus can be adversely affected by infections of the vaginal area such as thrush or cervicitis. If you wish to use this method of birth control, it is advisable to have a thorough pelvic examination to check for any pre-existing infection before you begin charting your mucus pattern. The use of vaginal sprays and douches, which is not recommended by doctors in any case, can also disguise the natural character of the mucus.