Cervical mucus – characteristics
Cervical mucus is produced by the glands in the cervix and the vagina. This mucus essentially has two functions:
• Protection against germs: Mucus forms a kind of block in the cervix. This creates a barrier which is difficult for germs to penetrate. The uterus is thus better protected against infections.
• Transport medium for sperm: The consistency of cervical mucus determines whether a man’s sperm can make its way through the vagina and into the uterus.
Cervical mucus – changes in the menstrual cycle
The hormone release from follicle-stimulating hormone (FSH), oestrogen and luteinising hormone (LH) not only regulates egg maturation and ovulation; it also changes the consistency of the cervical mucus. During the course of the menstrual cycle, it is fluid and clear on the fertile days around ovulation. In addition, similarly to egg white, it forms threads and can be stretched. This fluidity is ideal for allowing the man’s sperm into the uterus. On non-fertile days, cervical mucus is cloudy and white-coloured. The consistency is tough and therefore more impermeable to sperm.
Cervical mucus as an indicator of fertile days – symptothermal methods
To be able to better assess their menstrual cycle, women often check the consistency of their cervical mucus, which collects at the vaginal opening. The end of the woman’s fertile days is ascertained by measuring the basal body temperature. This is checked every morning after waking up and before getting out of bed. At the end of the fertile days, the temperature rises by about 0.2 °C and remains at this level until the start of the next cycle. Monitoring physical signs like this is referred to as a symptothermal method. To draw on this method as an indicator of fertile days, women need to monitor their bodies on a daily basis.
Cervical mucus after conception
Cervical mucus changes its density and colour throughout the course of the menstrual cycle. This means you can find out on which days you have a better chance of getting pregnant. However, you cannot tell whether fertilisation has taken place based on cervical mucus. This can be established only if you miss your next period.
Examination of cervical mucus during fertility treatment
A cervical mucus examination is part of the basic diagnostic process during fertility treatment, in order to check whether your cervical mucus is an optimal transport medium for sperm. To do this, the doctor will take a sample of the mucus on the days around ovulation. This is then examined in the laboratory. The permeability is assessed based on the so-called Insler Score.