Vaginal discharge changes through the month, these secretions (also known as cervical mucus or cervical secretions) are produced in the cervix and made up of 90-98% water. The consistency change is bought about by stringy molecules called mucins which respond to increasing oestradiol levels. The secretions tell us something about our cycles, whether we are in our fertile period, how strong ovulation is, and for us fertility acupuncturists, informs our diagnosis from a TCM perspective, so it is always a good idea to write down any changes on your Basal Body Temperature chart.
There are 5 types of cervical mucous
- Post period your vulva area feels dry and you may not even be aware of the G type mucous which is thick, pasty and impenetrable to sperm. At this time oestrogen is low.
- Oestrogen rises as the follicles in the ovary develop and grow the mucous becomes more liquid and wet, even sticky, you may be aware of a feeling of moistness or stickiness. You might notice as creamy or white secretions which hold its shape. The role of these secretions is to catch some of the abnormal/poor quality sperm (i.e. slow swimmers) before they reach the uterus. This is L -type mucous and when dried and see under a microscope, appears as branched ferns. (C)
- As the oestrogen increases the discharge becomes wetter and more stretchy.For some it can be quite profuse and the feeling is of slipperiness in the vulva. The role of the S-type fertile mucus is to provide a rapid transportation of the sperm to the uterus. To facilitate this the mucins are lined up longitudinally and appear as pine needles under a microscope. S-type or Spinn mucous is very stretchy and slippery like egg white. (A) If stretched between finger and thumb a thread can stretch to several centimeters. However, not every woman is aware of this, some just feel an increased wetness which is quite normal. The last day of stretch mucous is usually the day of the LH surge and peak fertility on an ovulation predictor kit.
- The P-type mucus, which very often is not distinguished from S-type, is the most fertile of all and gives sperm a final push to pass through the cervix into the uterus.It is not as thick and stretchy as S but it is extremely lubricative and feels slippery in the vulva. Under a microscope it makes hexagon shapes. (D)
- After ovulation progesterone increases and he mucous thickens again forming a plug across the oz of the cervix to prevent sperm from penetrating.Vulval secretions are white and sticky but they are no longer stretchy.
There are always variations from woman to woman and within a woman’s fertile period. Women with shorter cycles may not experience any dry days after the period, instead they go straight into being aware of a L type mucous. Others might find that after the mucous becomes dry again in the luteal phase, just before menstruation, secretions increase and have some of the characteristics of mucous earlier in the month – this is prompted by a drop in progesterone and a slight rise in oestrogen.
It’s worth bearing in mind that stress can disrupt cervical mucous patterns and if there are several attempts at ovulation shown by fluctuating secretions (and temperature peaks) follicles are developing but not quite producing enough oestrogen to trigger the LH surge and ovulation. This can often be the case with poly cystic ovaries (PCO), those with long cycles, and breast feeding mums when they start to drop a feed.