Ovulation occurs when a mature egg breaks out of its follicle in the ovary and is released. It usually happens in the middle of the cycle — in a 28-day cycle, ovulation would occur on the 14th day. But some people's cycles are longer or shorter than 28 days. Because this is the point at which an egg is ready to be fertilized by sperm, it's the most fertile time in the menstrual cycle.
Once released, the egg travels down the fallopian tube, where it survives for 12 to 48 hours. If it meets up with sperm, the egg is fertilized. The fertilized egg will then implant in the uterus. If conception doesn't occur, the egg will dissolve and the lining of the uterus will be shed during a menstrual period.
Some people have no symptoms and won't know they're ovulating. Some track ovulation by checking their cervical mucus or taking their basal body temperature. The most common symptoms of ovulation are:
Mild pain in the abdomen or pelvis, or mittelschmerz
Light vaginal bleeding or spotting
Thin, clear, slippery discharge from the vagina
Slight increase in resting (basal) body temperature
Sore, swollen breasts
Bloating
Moodiness
Increased sex drive
Changes in appetite
The ovulation process is controlled by hormones. The hypothalamus in the brain releases gonadotropin-releasing hormone (GnRH). GnRH then directs the pituitary gland to release follicle-stimulating hormone (FSH) and luteinizing hormone (LH).
The reason for these hormones is to help small sacs, called follicles, to release the egg.
Eggs develop in follicles inside the ovaries. Between the 6th and 14th day of the menstrual cycle, FSH and LH act on cells of the ovaries to help an egg mature. Between day 10 and 14, one egg fully matures. At around day 14, LH levels surge and trigger ovulation.
Some people know when they're ovulating because it happens at the same time each month or they have symptoms like sore breasts, bloating, or mood changes.
Another way to tell is by looking for signs of ovulation, like changes in cervical mucus or basal body temperature. During ovulation, vaginal discharge will become thin, clear, and slippery like egg whites, and the resting (basal) body temperature will rise slightly.
A home ovulation kit can determine with more certainty whether ovulation is happening. It contains a test that shows whether your urine contains LH, a hormone that's released right before ovulation. A positive result means that ovulation is likely to occur within 36 hours. The ovulation test that doctors use checks levels of hormones like progesterone in a blood sample to determine whether ovulation is happening.
Ovulation isn't a medical condition and it doesn't need treatment. But there are medications to treat people who don't ovulate regularly or who are looking to boost the number of eggs they release each cycle to improve their odds of getting pregnant.
Medication Options
When infertility is an issue, doctors can prescribe oral or injectable medicines like these to stimulate ovulation.
Clomiphene citrate (Clomid, Serophene) is a pill that stimulates the pituitary gland to release more FSH and LH, causing an egg to grow and be released.
Letrozole (Femara) also increases FSH levels to induce ovulation.
Gonadotropins (Menopur, Gonal-F, Follistum) are stronger medicines that trigger "superovulation," or the release of multiple eggs at once. These medicines can help people over 40 conceive by making several egg follicles develop at once.
Metformin triggers ovulation by improving insulin resistance, a common cause of infertility in women with polycystic ovary syndrome (PCOS).
Bromocriptine (Cycloset, Parlodel) helps with ovulation problems caused by excess production of the hormone prolactin from the pituitary gland.
Complementary and Integrative Therapies
Some couples try complementary and integrative therapies to help them conceive. Although these treatments aren't proven to boost ovulation or increase the chances of getting pregnant, some people find them relaxing during what can be a very stressful experience.
Birth control methods like the pill, patch, and vaginal ring contain the hormones estrogen and progestin, which prevent ovulation by controlling the release of hormones from the pituitary gland. Stopping ovulation helps prevent unwanted pregnancies. The morning-after pill is a form of emergency contraception that delays ovulation to prevent pregnancy.
Treating conditions that affect ovulation, like PCOS and thyroid disease, can improve ovulation if you're trying to get pregnant.
A few lifestyle changes can improve fertility, too.
Stay at a Healthy Weight
Obesity causes irregular menstrual cycles, and might even stop ovulation altogether. Without ovulation, a pregnancy can't happen. Conditions that are related to obesity, like diabetes and thyroid disease, can also affect ovulation.
A body mass index between 19 and 24 is considered ideal for ovulation and pregnancy. Your doctor can recommend a diet and exercise program to help you stay at a healthy body weight.
Avoid Unhealthy Habits
Any of these things might alter hormone levels in ways that disrupt ovulation.
Smoking: Chemicals in tobacco smoke lower levels of estrogen and progesterone. This drop in hormones can cause a reduction in egg quantity and quality. Smoking also damages the DNA in eggs, increasing the risk for miscarriage and birth defects.
Heavy alcohol use: Drinking more than one or two alcoholic beverages each day could affect ovulation. Abstention from alcohol is best when you’re trying to conceive.
Caffeine: While one or two small (6- to 8-ounce) cups of coffee a day shouldn't affect the ability to get pregnant, drinking more than that might cause problems with ovulation and reproduction.
Chemical exposure: Exposure to pesticides, heavy metals, dry cleaning chemicals, and other toxins in the environment and at work might have a negative effect on ovulation and fertility.
Exercise in Moderation
Moderate aerobic exercises like walking or riding on a stationary bike may help with ovulation and fertility. But very intense exercise could have the opposite effect, especially in people who are already at a healthy weight. Working out for too long or too hard might actually stop ovulation and menstrual periods and make it more difficult to conceive.
Ovulation doesn't cause complications, but several conditions cause problems with ovulation. All these disorders can lead to issues with egg production and fertility.
Premature ovarian failure, which is when the ovaries stop working before age 40
Too much prolactin, a hormone made by the pituitary gland that stimulates milk production after childbirth
Ovulation pain, or mittelschmerz, is pelvic pain that affects some women during ovulation.
It's usually felt in the lower belly or pelvis, often on the side where the egg is released. Mittelschmerz isn't harmful and it shouldn't affect fertility.
Ovulation is the time during the menstrual cycle when a mature egg is released from the ovary, usually around day 14 of the menstrual cycle.
Infertility drugs stimulate ovulation in women who are trying to conceive. Hormonal birth control stops ovulation.
Smoking, exposure to toxic chemicals, exercising too vigorously, and drinking alcohol to excess can affect ovulation.
If you experience any concerning symptoms during ovulation, such as persistent pain, it's critical to see a healthcare provider for evaluation to rule out underlying conditions.
