When Is Ovulation? Signs of Ovulation and Ovulation Pain

In brief:

• An egg develops and is released in each cycle; sometimes more than one egg can be released (NHS).
• It is hard to predict the exact day of ovulation; if your cycle is shorter or longer than 28 days, the day of ovulation changes too (NHS).
• The egg lives for about 24 hours after ovulation. Sperm can live in the body for 3, sometimes 5 days (ACOG); according to the NHS, up to 7 days.
• One in five women has one-sided pelvic pain around ovulation (MedlinePlus).
• Basal body temperature rises after ovulation; it does not signal ovulation in advance (ACOG).

What is ovulation?

According to the NHS, the menstrual cycle is controlled by hormones. Oestrogen, which rises in the first half of the cycle, makes an ovary develop and release an egg; this is called ovulation. The womb lining also starts to thicken. In the second half of the cycle, progesterone prepares the womb for a possible pregnancy.

The egg travels down the tube towards the womb. If there is no pregnancy, oestrogen and progesterone fall, the womb lining is shed and the period starts (NHS). A woman is born with all her eggs; once periods start, usually one egg develops and is released in each cycle (NHS).

We explain FSH, one of the hormones that control ovulation, in What Is FSH and What Should Your Level Be? High and Low FSH.

When does ovulation happen?

• NHS: for most women ovulation happens about 10–16 days before the next period. Women with a regular 28-day cycle are fertile around day 14; for those with shorter or longer cycles this day is different.
• ACOG: in an average 28-day cycle, ovulation happens about 14 days before the next period. The part of the cycle that changes least is the time between ovulation and the next period.

Day 1 of the cycle is the day your period starts. According to the NHS, regular cycles of 21 to 35 days are normal. If your periods are irregular, you may not ovulate regularly either, which can make it harder to get pregnant (NHS).

Counting on a calendar: one calendar method treats days 8 to 19 as the most fertile days in women whose cycles are between 26 and 32 days long (ACOG). This method works best when cycles are regular. If your cycle is irregular, the calendar alone can mislead you.

On which days can you get pregnant?

According to ACOG:

• The egg lives in the tube for about 24 hours after ovulation.
• Sperm can live in a woman's body for about 3, sometimes 5 days.
• So sex from 5 days before ovulation until 1 day after can lead to pregnancy. The chance of pregnancy is highest when live sperm are in the tubes at the time of ovulation.

The NHS says sperm can live for up to 7 days before ovulation. So the fertile window can extend to earlier days of the cycle. According to the NHS, if ovulation is early or the cycle is short, it is also possible (though unlikely) to get pregnant right after a period ends.

What are the signs of ovulation?

Change in discharge: according to the NHS, around ovulation vaginal discharge becomes thinner, stretchier and like raw egg white. According to ACOG, just before ovulation the mucus produced by the cervix increases noticeably and becomes thinner and slippery; after ovulation it decreases and thickens. We explain how discharge changes over the cycle in When Is Vaginal Discharge Normal?.

Basal body temperature: your body temperature when fully at rest. According to ACOG, in most women it rises slightly (0.5–1 °F, about 0.3–0.5 °C) at ovulation and stays higher until the end of the cycle. The most fertile days are the 2–3 days before this rise. But the temperature rise appears after ovulation has happened, so it does not signal ovulation in advance. If you have a fever, the method is not reliable (ACOG).

Ovulation pain: according to MedlinePlus, one in five women has pain around ovulation (mittelschmerz). The pain:

• is on one side of the lower tummy;
• lasts from a few minutes to a few hours, sometimes 24–48 hours;
• is sharp and cramp-like;
• can switch sides from month to month;
• starts in the middle of the cycle.

Testing devices: some devices sold in pharmacies try to show the fertile days by measuring hormones in urine (ACOG).

Is ovulation pain dangerous?

According to MedlinePlus, ovulation pain can be uncomfortable but is harmless and is not a sign of disease. Usually no treatment is needed; if the pain is severe or lasts long, painkillers can be used.

Still, because more serious conditions that need treatment can cause similar pain, it is important to talk to your doctor about your pain (MedlinePlus).

Is tracking ovulation safe as contraception?

According to ACOG, with fertility awareness methods used perfectly, 1–5 in 100 women get pregnant in the first year. With typical use in real life this rises to 12–24 in 100. These methods are harder to use if your cycle is irregular or you bleed between periods (ACOG).

We explain emergency contraception after unprotected sex in The Morning-After Pill: Everything You Need to Know.

When should you see a doctor?

• Your ovulation pain has changed, lasts longer than usual or comes with bleeding (MedlinePlus)
• Your periods are irregular and you are struggling to get pregnant (NHS)
• There is a change in your discharge that worries you (NHS)

Frequently asked

What does discharge look like around ovulation?

According to the NHS, around ovulation discharge becomes thinner, stretchier and like raw egg white. According to ACOG, the amount increases noticeably and it becomes slippery; after ovulation it decreases and thickens.

How many days does ovulation last?

Ovulation is a single event in which the egg is released. The egg then lives for about 24 hours. Because of how long sperm live, the window in which pregnancy is possible is about 6 days: from 5 days before ovulation to 1 day after (ACOG).

Can you get pregnant right after your period?

It is unlikely but possible. According to the NHS, if ovulation is early or the cycle is short, you can get pregnant right after your period ends.

Which side is ovulation pain on?

It is felt on one side of the lower tummy, on the side where the egg is released. According to MedlinePlus, it can switch sides from month to month or stay on the same side for months.