What is ovulation?
Ovulation is when you release an egg from one of your ovaries. If that egg gets fertilized by a sperm and implants in your uterus, you’re pregnant!
You’re potentially fertile beginning five days before you ovulate through the day of ovulation, although you’re much more likely to get pregnant if you have sex during the final three days of this window.
There’s no foolproof method to predict when you’ll ovulate. But here are a few ways you can estimate when it’s most likely to happen, so you can try to time sex accordingly and boost your chances of getting pregnant.
Try the calendar method
If your cycle is regular – the same number of days each time – you can try the calendar method (also known as the Standard Days Method).
To estimate when you’ll ovulate, count back 14 days from when you expect your next period. Your fertile window includes the day you ovulate and the preceding five days. So, for example, if day 1 is the first day of your period and day 28 is the day before you expect your next period, you’d be fertile on days 10 through 15.
This method is the easiest way to estimate your fertile window, but it’s not very accurate, even if you have a good idea of when your next period will start. That’s because ovulation rarely happens exactly 14 days before menstruation.
In one large study, the day of ovulation varied from seven to 19 days before menstruation among women with 28-day cycles. Ovulation happened 14 days before a period only 10 percent of the time.
So you can see how it’s possible to miss your fertile window altogether using this method. On the other hand, it’s easy and free and worth a try, especially if you’re not in a hurry to conceive.
You can use BabyCenter’s Ovulation Calculator to find out which days you’re likely to be fertile according to the calendar method and what your due date will be if you conceive.
Use an ovulation predictor kit
Testing your hormone levels with an ovulation predictor kit (OPK) is another method. There are two kinds of kits: The most common type tests your urine, and the other tests your saliva. Both show a positive result in the days before you ovulate, giving you time to plan ahead for baby-making sex.
The pee-on-a-stick test indicates when your level of luteinizing hormone (LH) has gone up, which usually means one of your ovaries will soon release an egg. With the saliva test, you use a microscope to spot a pattern in your dried saliva that indicates the rise in estrogen which happens in the days before ovulation.
The kits are available at drugstores without a prescription. But they can be costly at $20 to $50 each.
Learn more about ovulation predictor kits.
Chart your ovulation symptoms
You can also track subtle changes in your basal body temperature (BBT) and cervical mucus for a few cycles to try to determine when you ovulate.
If you pay attention to these clues and note them on a chart, you may see a pattern that can help you predict when you’re likely to ovulate next. (If your periods are irregular, you may not notice a pattern.)
Your BBT is your lowest body temperature in a 24-hour period. You have to measure it every morning with a special thermometer and record it on the chart. On the day after you ovulate, you should see an uptick of 0.5 to 1.0 degree Fahrenheit in your BBT. This temperature increase typically lasts until your next period.
Cervical mucus is the vaginal discharge you sometimes find in your underwear. For most of the month, you may have very little of it, or it may be thick and sticky. But in the three to four days before, during, and immediately after ovulation, you’ll notice an increase in cervical mucus and a change in its texture. It’ll be clear, slippery, and stretchy, like raw egg whites.
Charting is free (after you buy the thermometer), but this method takes time and effort to do accurately.
Take note of mild cramping
Some women report that they feel mild cramps or twinges of abdominal pain, or a one-sided backache around the time of ovulation. These sensations are known as mittelschmerz. Although it isn’t a precise way to determine when you’re ovulating, it may be helpful to be aware of these symptoms (if you have them) while using the calendar, BBT, or cervical mucus methods..