When you’re trying to conceive, timing is everything. There’s a small window during which you need to have the sperm ready to meet the egg. So how do you know when your window has arrived? Thankfully, at-home ovulation tests can give you that answer and help you plan the best time for baby making.
The most common tests analyze your urine for an increase in luteinizing hormone (LH), says Beth Taylor, an infertility specialist at Olive Fertility in Vancouver. This hormone peaks, in what’s known as an LH surge, a day or two before an egg is released and then declines once ovulation has occurred.
A positive result on one of these tests—usually indicated by a line that is equal to or darker than the test line—means that it’s time to get busy, says Ashley Gilman, a Toronto OB-GYN who specializes in reproductive endocrinology and infertility. Since sperm can survive in your cervical mucus for up to five days prior to ovulation and an egg only lasts for about 24 hours, having sex just before you ovulate will help maximum your odds of conceiving by ensuring that you have sperm waiting to meet the egg when it’s released.
A few urine tests also look for estrogen, which rises one to three days before the LH surge. Taylor explains that this gives you a bigger fertile window and makes dual-hormone tests a good option for couples who want to maximize their chances of conceiving or have tight schedules.
Toronto mom Sara Morrow* used urine-based tests to help her conceive three times. “They were easy to use and interpret,” she says. She also liked how the tests confirmed that the eggy white discharge she saw was a sign of ovulation. “These tests help you learn more about your body,” she says.
But she wasn’t a fan of the price. A 20-test kit (which can last one to two months) starts at about $60, while a 10-test dual-hormone kit costs around $70.
Gilman notes that, though urine-based tests are very accurate, they aren’t for everyone. Women who have medical conditions like polycystic ovary syndrome or who use certain medications (particularly those that contain hormones) should skip these tests because these factors may lead to incorrect results.
Women who have highly unpredictable cycles are also poor candidates. “Let’s say someone gets a period only once every three months,” says Gilman. “You won’t know when to start testing, so you could be testing every day for three months, which is costly and stressful.” She encourages women who don’t have regular periods to see their healthcare practitioners because it could be a sign of a medical condition or indicate that they’re not ovulating.
One other drawback? While an LH surge is needed to trigger ovulation, it doesn’t always mean that you’ll release an egg. “You might get a positive and then not ovulate that month for reasons that we don’t totally understand yet,” says Gilman. But, thankfully, that’s rare. “If you have a regular cycle and you’re using urine ovulation tests and they give positive results, you’re most likely ovulating.”
For the most accurate results, Taylor recommends using your second urine of the day. She says most women get their LH surges in the early morning and their first pee might be diluted by fluids that have built up while sleeping.
Before using an ovulation predictor kit, Morrow tried deciphering her cycle herself by tracking her basal body temperature (BBT). Your BBT is your body’s temperature when it’s fully at rest and, for most women, it’s somewhere between 36.1C (97F) and 36.4C (97.5F) prior to ovulation. After you release an egg, it increases slightly to between 36.4C (97.5F) and 37C (98.6F). Though your BBT won’t give you an immediate heads-up on when you’re going to ovulate, following it over several weeks can help you see when you’ll likely ovulate next.
But it’s not always as easy as it sounds. “You have to take your temperature first thing in the morning, before you get out of bed, and I always forgot,” says Morrow. Tracking your BBT also requires a thermometer that displays your temperature accurately, down to at least one-tenth of a degree.
These thermometers generally start at $25, so they’re less expensive than urine tests, and there are apps like Kindara, Glow and Clue that can help make tracking your temperature easier. Still, tracking BBT is finicky—anything from being ill to sleeping in a different room can affect it—which makes it less accurate than urine-based tests, notes Taylor. Rather than predict when you’re about to ovulate, it helps you establish a general pattern of when you’ll ovulate over time, so it’s not ideal for women with irregular cycles.
Another way to demystify your cycle is to examine your spit using a saliva-based ovulation test. With these tests, you place a drop of saliva on a glass slide and examine it using the tiny microscope provided in the kit. Since the composition of saliva changes with hormone levels, women who experience pre-ovulation increases in estrogen may be able to see distinctive, fern-like patterns in their samples.
“I tried for eight months without tracking and got pregnant with my son the first month I used the saliva test,” says Calgary mom Leslie Mae*, who also used a saliva test while trying to conceive her daughter two years later. Initially, using the kit took a bit of trial and error, but it was really easy to understand the results once she mastered getting her spit on the slide. Mae adds that her husband also enjoyed examining the slides. “It was nice to be able to share that,” she says.
Though Mae recommends the saliva tests, studies are mixed on their accuracy at predicting ovulation, with efficacy rates varying from 42 to 90 percent. User error is a major concern because something as small as an air bubble can affect the result and saliva ferning is poorly understood. Some factors that can influence results include smoking, eating and drinking before using the test. Taylor recommends urine-based ovulation tests over saliva-based ones, adding that she doesn’t see a benefit to the saliva tests beyond the potential cost savings. While spit-based ovulation tests cost around $65, they are reusable, making them cheaper in the long run.
“All of these methods can be a little cumbersome,” says Gilman, who acknowledges that fertility tracking can be very stressful. “I think people should choose the method that is least stressful for them.”
*Name has been changed