One method of fertility monitoring uses changes in cervical mucus to predict ovulation.
When a person is fertile, the cervical fluid is watery, thin, and slippery, and it may appear similar to an egg white.
What is cervical mucus?
Ovulation is when an ovary releases an egg for fertilization.
Cervical mucus is fluid that the cervix releases into the vagina. It has several functions, including keeping the vagina lubricated and preventing infection.
Throughout the menstrual cycle, hormonal shifts influence the amount, texture, and appearance of cervical mucus.
There may be enough mucus for a person to notice it in their underwear. Although the cervix always produces some mucus, it makes more right before and after ovulation.
So, if a person notices an increase in vaginal discharge, they may be seeing fertile cervical mucus.
What is fertile discharge?
Fertile discharge is thin, clear or white, and slippery, much the same as an egg white. This type of discharge signals that ovulation is approaching.
Fertile cervical fluid helps sperm move up the cervix to fertilize an egg. It also keeps the sperm healthy during the journey.
People usually notice fertile discharge a few days before ovulation. The discharge may become wetter and more slippery over several days. After ovulation, the amount of discharge usually decreases.
A ripening egg grows inside an enclosure, called a follicle, in the uterus. The follicle grows and produces estrogen. When the follicle ruptures, the body ovulates, releasing an egg.
The estrogen that the follicle produces softens the cervix and opens it slightly. Estrogen also changes the texture of cervical fluid, making it more able to support fertility.
Cervical mucus timeline
Everyone's cervical fluid is slightly different. So, to detect fertile discharge, a person should monitor their cycle for several months.
The days that discharge changes vary from person to person. Those who ovulate later in their cycle, for example, should expect fertile discharge after day 14.
In general, the cycle of discharge follows this pattern:
- Early cycle (days 1–5): This is when menstruation occurs.
- Post-period (days 5–10): At first, there may be little or no discharge, but sticky, glue-like fluid may follow. This is a time of low fertility.
- Pre-ovulation (days 10–14): The body starts to produce more estrogen. The sticky fluid may thin and look cloudy. Eventually, it gets slippery and begins to look like egg whites.
- Ovulation (day 14): On the day of ovulation, many notice that their cervical fluid is very wet and viscous. A person may be able to stretch the fluid an inch or more between their fingers.
- Post-ovulation (days 14–22): After ovulation, the body releases the hormone progesterone, which dries up cervical fluid. The discharge may look cloudy at first, then become thicker.
- Pre-period (days 22–28): As a period approaches, the discharge may have a glue-like consistency again. There tends to be little or no discharge 1–2 days before menstruation. Some people notice spotting just before their period.
Ovulation plays a significant role in determining the consistency of cervical fluid. A person who does not ovulate may notice fewer changes in their vaginal discharge.
A person who ovulates very late or early may find that their cycle does not follow the "typical" schedule.
When is a person most fertile?
A person should monitor their cycle for several months to detect fertile discharge.
Fertile cervical fluid is a good signal of increased fertility. Anyone trying to get pregnant should have intercourse during the time when they notice the fertile discharge. Doctors call this the "fertile window."
An egg only lives 12–24 hours after ovulation, but sperm can live much longer, often 3–5 days in fertile cervical fluid.
This means that, for people wishing to become pregnant, the best time to have intercourse is right before ovulation, as sperm can live in the reproductive tract for several days. If they are already there when ovulation occurs, they can immediately fertilize the egg.
How to check
To determine fertility, check the appearance of cervical fluid at least once a day, beginning on the first day after a period.
It can help to keep track of daily changes in a diary or to use a monitoring app.
To check for cervical fluid:
- After using the bathroom, wipe the area around the vagina to remove any excess pee, which can change the appearance of cervical fluid.
- Pat the area with toilet paper. Make a note of any visible fluid.
- Wash the hands. Gently insert a finger about half an inch into the vagina.
- Remove the finger and note the color, texture, and general appearance of the fluid.
- If the fluid is clear, thin, watery, and stretchy, it may be fertile cervical discharge.
Several factors can influence the way that cervical fluid looks, which is why a person should monitor the appearance and consistency over time, to get a sense of what is normal for them.
Some people find that their cervical fluid looks different after sex. For example, when semen mixes with vaginal fluids, this can change the appearance of vaginal discharge. Soap, lubricants, and other products that can also result in changes.
Some people produce less fertile cervical mucus, so they may not notice it.
Others produce no fertile cervical mucus, and this indicates a problem with ovulation. Some medical conditions, such as polycystic ovarian syndrome, or PCOS, make ovulation less likely. Being underweight can also cause the body not to ovulate.
As a person approaches menopause, they may ovulate less frequently. Some people run out of eggs early, which a doctor would diagnose as a decreased ovarian reserve. This can cause a person to ovulate irregularly, if at all.
Keeping track of the appearance and consistency of cervical fluid can help a person determine when they are fertile.
This method is most reliable when a person has monitored changes in fluid for several cycles. When it comes to cervical fluid, everyone has a different "normal." A person who knows their usual pattern can more easily spot signs that they are about to ovulate.
Many people also use other methods of tracking fertility, such as basal body temperature monitoring and ovulation testing. A combination of approaches can provide more certainty about ovulation.
It is important to note that having fertile cervical fluid is not a sure sign of fertility.
The body may release high levels of estrogen, even though a person does not ovulate. However, in general, if a person does not ovulate, they are much less likely to have fertile cervical fluid.
While home methods of monitoring ovulation may help, the only way to verify ovulation is to see a doctor or midwife.