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Q&A About Ovulation With a Reproductive Endocrinology and Infertility Specialist

With Jessica Walter, MD

Your body may experience changes during your menstrual cycle. Your mood may change, you may become bloated and experience breast tenderness and headaches. That's why many people opt to track their menstrual cycle. For people who are trying to get pregnant, it can also be helpful to track your ovulation to increase your chances of fertilization.

For those looking to avoid pregnancy who are not using other birth control methods, it can be helpful to track your ovulation schedule so you know when not to have sexual intercourse.

Northwestern Medicine Reproductive Endocrinology and Infertility Specialist Jessica Walter, MD, answers frequently asked questions about tracking ovulation.

Q: What is ovulation? 

During the first part of the menstrual cycle (following your period) the ovary grows a follicle, or a fluid-filled sac. During ovulation, the follicle in the ovary breaks open to release the egg inside. This egg travels down the fallopian tubes that connect your ovaries (where your eggs are) to your uterus. The egg will be able to be fertilized 24 hours. Contrary to popular belief, sperm can live in the female reproductive tract for up to five days. If it is fertilized by a sperm, it may implant in the uterus and start developing into a fetus. If not fertilized, the egg will dissolve.

Q: When does ovulation occur during your menstrual cycle and how many hours does it last? 

A: Ovulation typically occurs halfway through a menstrual cycle. In the average 28-day menstrual cycle, ovulation occurs around day 14. However, there is normal variation in the overall length of a menstrual cycle, and any cycle between 21 and 35 days is considered normal. The best way to estimate when you ovulate is to count backwards 14 days before the start of your next menstrual period.

Ovulation lasts for approximately 12 to 24 hours.

Q: What symptoms might you experience during ovulation?

A: This process can lead to some bleeding and release of inflammatory fluid into the belly from the rupturing follicle. This can be uncomfortable. As a result, some women experience mild abdominal bloating, cramping, or pelvic pain. Others experience a change in cervical mucus or breast tenderness. Cervical mucus around the time of ovulation is often characterized as like egg whites. It becomes slippery and stretchy in consistency and clear in color. It is important to note that some individuals have no symptoms during ovulation.

Q: Why might it be helpful to track ovulation if you're trying to conceive?

A: Tracking ovulation while you are trying to conceive will help you and your partner time sex appropriately to maximize your chances of pregnancy.

Who can benefit from doing this?

A: Tracking ovulation is helpful for people who are trying to conceive. First, if the menstrual cycle is regular (coming roughly every month) and ovulation or signs of ovulation are detected each month, this helps an individual understand that they are "ovulatory," meaning their body is appropriately recruiting a follicle and making an egg each month.

Secondly, knowing when ovulation occurs helps to identify the ideal time to have sex. The "fertile window" is a six-day period that ends on the day of ovulation. The highest rate of pregnancy has been demonstrated in multiple studies to occur if couples have sex during the one to two days immediately preceding ovulation. Tracking the timing of your own cycles helps identify the most optimal times to engage in intercourse.

Tracking ovulation is also beneficial for individuals using donor sperm, it helps people time inseminations that are performed either at home or with a gynecologist or fertility specialist.

If an individual finds that they are not regularly having ovulation, this could prompt an earlier evaluation with an obstetrician/gynecologist or reproductive endocrinologist.

Having a basic understanding and awareness of how your body works can be empowering for all people, even if your immediate goal is not to conceive. For example, tracking ovulation can also help individuals or couples time sex outside of the fertile window — if the goal is to avoid pregnancy. Some people track ovulation as part of the rhythm method to prevent pregnancy.

Q: What's the best time during your cycle to start tracking ovulation (and why)?

A: The best time to start tracking your ovulation depends on the length of your menstrual cycle. Assuming you have a 28-day cycle, and you anticipate ovulation to occur halfway through the cycle on day 14, we recommend starting to track on cycle day 10, with cycle day one considered the first day of full menstrual flow. Ovulation can sometimes be unpredictable, so if you want to be sure you do not miss ovulation, you can always start to track earlier.

Q: What are tracking strategies and tools I can use?

A: Calendar method: For the calendar method, you can track the first day of each menstrual cycle. Ovulation occurs roughly halfway through the cycle, or 14 days before your next period, so you can estimate which days you will have peak fertility. It is important to note that calendar-based methods rely on an assumption that ovulation always occurs 14 days prior to the next period. There is natural variation in the timing of ovulation and this estimation may not always be accurate.

There are also tracking apps that you can use that mimic the calendar method, but some use algorithms to estimate when you are most likely to ovulate.

Basal body temperature method: Your basal body temperature is your temperature at rest, and it is typically determined by measuring your temperature each morning at roughly the same time prior to getting out of bed. Ovulation causes a slight increase in an individual's basal body temperature. Peak fertility occurs during the two to three days preceding a rise in basal body temperature.

Cervical mucus method: Around the time of ovulation, some individuals notice that their cervical mucus increases in quantity, becomes clear, stringy and slippery. The cervical mucus around ovulation is sometimes likened in quality to egg whites. This can be an indication of impending or recent ovulation.

Ovulation predictor kits: Ovulation predictor kits traditionally have individuals urinate on a stick once a day in the morning. The sticks measure a hormone in the urine called luteinizing hormone, also known as LH. LH surges, or rises rapidly, immediately prior to ovulation. The ovulation predictor kits detect this elevated level of LH in the urine. Ovulation occurs roughly 24 hours after the LH surge is detected in urine. A positive test indicates detection of LH in the urine and is suggestive of ovulation within the next 24 hours. This can help to time intercourse or inseminations.

Q: How long does it typically take to get pregnant after you start tracking your ovulation?

A: Nearly 80% of all couples will become pregnant in the first six months of trying to conceive. Remarkably, the overall rate of conception in any month for a couple with no infertility is relatively modest — at only about 25%. You should not be discouraged if you do not become pregnant after the first few months of trying.

Q: When should you see a doctor if you're trying to conceive and haven't had success? 

A: If you are younger than 35 and you have been actively trying to conceive for 12 months, you should see a fertility specialist, such as a reproductive endocrinologist. Because of age-related decline in fertility (both conception rates and live birth rates), we recommend that if you are 35 years or older, you should be evaluated by a doctor sooner, after only 6 months of trying. Earlier evaluation may be warranted outside of these recommendations based on an individual's medical, obstetrical or gynecological history — such as endometriosis or polycystic ovary syndrome.