Updated October 16, 2019
To get pregnant fast, the most important question is: When do you ovulate? This is when the ovary releases the egg so that it can be potentially fertilized by a sperm cell. The five days leading up to ovulation and ovulation day are the only days that you can get pregnant. You generally have a higher chance of pregnancy the closer you are to ovulation day.
While there are some free ovulation calculators that will give you an estimate of when you ovulate by using some ovulation symptoms that you can monitor, the majority of women will choose to use an ovulation test to get pregnant fast.
What is an Ovulation Test?
An ovulation test, also called an Ovulation Predictor Kit (or OPK), detects the concentration of luteinizing hormone (LH) in your urine. An LH surge will reach its peak 24-36 hours before you ovulate. The test normally will show a positive result when the LH surge occurs.
What is an LH Surge?
Levels of luteinizing hormone (LH) stay low normally, but increase before ovulation.
LH will increase to its peak 24-36 hours before ovulation. The process where LH increases from low to peak is called the LH surge. How long the LH surge lasts can vary from woman to woman. During the LH surge, LH can reach its peak in just a few hours, or it can take up to 6 days to reach peak before ovulation.
The table below shows you the average LH concentration in urine at different stages.
Knowing Your LH Surge Matters
Many women have the misconception that ovulation tests will only show one day of a "positive" result. That is not always true! This is only true for women whose LH surge lasts for less than one day. In reality, over half of studied women have an LH surge that lasts longer than one day. Accordingly, ovulation tests will show positive results for more than one day. Though there is a variety of surge patterns for TTC women, there are two that matter most in understanding how to use ovulation tests correctly to accommodate your pattern.
Pattern 1: Gradual Onset See the picture example below. This LH surge lasts for 5 days. Cycle Day (CD) 17 is the peak day, when you will see the darkest test line out of all your observed ovulation strip test lines. CD 14 - CD 16 are the days you will still see a darker test line than the faint negative test line of previous days.
If you've gotten positive ovulation tests for several days, don’t worry! This is normal. You are also fertile during those days because sperm can live in the body for up to 5 days, while an egg can live for only 24 hours. If you want to boost your chances of getting pregnant and want to be more certain of ovulation day among all the positive results, know that the darkest line is your peak day, which signals that the egg will be released from the ovary within the next 24-36 hours.
Pattern 2: Rapid Onset The LH surge can happen quickly within a few hours. See the example below. Unlike the gradual onset pattern, women with rapid onset pattern may only detect one positive ovulation result despite consecutive days of testing.
No matter which pattern you have, you are not alone. 57.1% of studied women are the gradual LH surge type while 42.9% are the rapid LH surge type.
If you have a gradual onset pattern, you won’t need to worry about missing your LH Surge with ovulation tests if you test consistently before your predicted ovulation day. However, if you have a rapid onset pattern, you may easily miss your LH surge if you don’t test during the short LH surge time window.
It is important to know your pattern if you want to use ovulation tests effectively. The quickest way to track your pattern is to use the Premom Ovulation Calculator, the first ovulation predictor & period tracker app that allows you to view your LH hormone progression throughout your ovulation cycle.
Here are important tips to follow for the best use out of your ovulation tests:
- Start testing early in your cycle to find a negative test result as a baseline. This will help you identify the darker lines as the LH increase begins; it also helps the app’s algorithms to calculate the LH levels from the very beginning of the cycle.
- Upload the photo of the ovulation test results to the test gallery in the Premom app. The tests will be automatically aligned in your gallery.
- During your 1st cycle while using ovulation tests or Premom, keep testing once a day in the beginning, and test twice when the test line begins getting darker.