Peak fertility is the part of a woman’s cycle when ovulation happens and the chances of pregnancy are highest. It lasts about 6 days and usually occurs about 10 to 14 days after the first day of the menstrual period.
Peak fertility can be identified through signs and symptoms such as clear vaginal discharge, acne breakouts, a rise in body temperature, lower abdominal pain, mood changes, and increased appetite.
Knowing exactly when peak fertility happens is important for people trying to get pregnant, because it helps pinpoint the most fertile days. However, peak fertility timing should not be used as a natural birth control method.
Main symptoms
The main symptoms of peak fertility include:
1. Clear vaginal discharge
Clear vaginal discharge that looks like raw egg whites is often the first sign that peak fertility is approaching. During this phase, the body releases a hormone called estradiol, which increases fluid production and provides natural lubrication that helps sperm enter the vaginal canal.
When cervical mucus becomes thinner and clearer, it not only signals peak fertility but also helps sperm travel more easily to the egg, increasing the chance of fertilization.
2. Acne breakouts
Acne breakouts often occur around times of peak fertility, as hormonal changes can make the skin oilier, increasing the likelihood of blackheads and pimples, even well beyond the teenage years. Read more about types of acne.
3. Slight increase in temperature
A slight rise in body temperature occurs as the body prepares for fertilization. During this phase, the follicles release an egg and produce more of the hormone progesterone, which increases body temperature by about 0.3 to 0.8°C (0.5 to 1.4°F). This change can be detected with a thermometer immediately after waking up.
4. Increased sex drive
Higher hormone levels can sometimes lead to an increased sex drive, making a woman feel more attractive and experience greater sexual desire.
5. Lower abdominal pain
Lower abdominal pain (pain in the lower belly, around the level of the ovaries) is one of the most common symptoms. Some women may feel cramping pain that comes and goes, which can be a clear sign that ovulation is happening.
6. Irritability and mood swings
Mood changes are also common during peak fertility, mainly due to the hormonal shifts typical of this phase.
Women who are trying to get pregnant but have difficulty calculating their fertile period or recognizing their symptoms can choose to take an ovulation test, which can be purchased at a pharmacy.
When it happens
Peak fertility usually occurs 10 to 14 days after the first day of the period and lasts about 6 days.
How to calculate
To find out when peak fertility happens, enter your information into the calculator below:
To calculate peak fertility manually, add 14 days to the first day of the last period, then count 3 days before and 3 days after to identify the 6-day window that corresponds to peak fertility.
What is the most fertile day?
The most fertile day is the day of ovulation, along with the 3 days before and the 3 days after ovulation. During this time, fertilization is more likely to happen if there is unprotected sexual contact, increasing the chance of pregnancy.
In addition, because the egg has a “life span” of about 24 hours after being released by the ovaries, the day after ovulation can also be one of the most fertile days.