How to Read Ovulation Test Lines

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How to Read Ovulation Test Lines

For couples trying to conceive, a proper understanding of a woman’s menstrual cycle and ovulation period is essential to reduce the time to pregnancy and associated stress.

In a perfect menstrual cycle, ovulation occurs on the 14th day, of a 28 day menstrual cycle. However, this only occurs in less than 20% of cycles among completely normal women making it difficult to time intercourse with ovulation. Fortunately, there are a few options available on the market to help women test whether or not they due to ovulate. 

Ovulation sticks, sometimes also called ovulation predictor kits (OPKs) or simply ovulation test strips are urine-based tests that women can use at home to detect imminent ovulation. They work by detecting a hormone called luteinizing hormone (LH) in the urine which rapidly increases (or surges) approximately 35 to 44 hours before ovulation.

Ovulation test strips are easily available and less intrusive than other methods such as transvaginal sonography.

These tests always have 2 lines. One line is the known as the control line which indicates if the test was used correctly and is working, while the second line is known as the test line.

Do Ovulation Sticks Get Darker The Closer To Ovulation

The second line on an ovulation test (stick) becomes dark or darker than the control line the closer a woman is to ovulation. This is because the levels of LH in your urine is increasing towards the ovulation positive test level set by the manufacturer.

No Line On Ovulation Test

No line on an ovulation test means the test did not work because the absorbent tip wasn’t saturated with enough urine, the ovulation test is damaged or the ovulation test has expired.

Only One Line On Ovulation Test

Only one line on the ovulation test happens if you tested too early or too late in your cycle, or failed to ovulate during your cycle.

The majority of women (>75%), without any known conditions, ovulate anywhere between cycle day 12 to 17, meaning testing from cycle day 10 to 16 is most likely to identify your LH surge.

While is it not abnormal for women to experience an anovulatory cycle once in a while, meaning no LH surge, it is better to see a medical professional if this continues for a few months.

Faint Line On Ovulation Test, Could I Be Pregnant

A faint line on an ovulation test indicates you are not pregnant. Only two solid lines on an ovulation test, performed outside your ovulation window, would suggest you are pregnant. This is because at-home ovulation tests can not distinguish between LH and human chorionic gonadotropin (hCG) in your urine.

Two Lines On Ovulation Test, Could I Be Pregnant

Two lines on an ovulation test could indicate you are pregnant if the test was performed approximately 2 weeks after ovulation. This is because LH is molecularly similar to the pregnancy hormone human chorionic gonadotropin (hCG) and at-home ovulation tests can not distingush between the two hormones.

To be more specific, the majority of ovulation tests use a LH test threshold of 25 mIU/ml. This means ovulation tests could in theory detect hCG levels above this threshold 12 days after ovulation following successful conception.

However, ovulation tests are not as reliable as pregnancy tests in detecting pregnancies and it is recommended to use the latter to see if you are pregnant.

How Long Will An Ovulation Test Stay Positive

An ovulation test can stay positive 1 to 2 days after the initial positive test. This is because the LH surge is sometimes longer than normal and therefore levels of LH in the urine have not dropped below the test threshold.

A Tip From Fertility Science

Although ovulation tests are a simple and effective way to help predict ovulation, they are by no means perfect.

In a related study, positive ovulation tests failed to correctly predict ovulation within 24 hours, in approximately one-third to one-half of cycles, among completely normal women.

However, the same study also found that the simultaneous use of cervical mucus and ovulation tests improved the prediction of ovulation among the same women.

Overall, ovulation predictor kits (OPKs) allow women to understand their cycle better and seek medical assistance earlier if required.

The fact is OPKs are not a miracle treatment and they do not decrease the time-to-pregnancy significantly. This is because there are many factors involved in successful conception other than timed intercourse.

References

Yeh P T, et al. (2019). Should home-based ovulation predictor kits be offered as an additional approach for fertility management for women and couples desiring pregnancy? A systematic review and meta-analysis. http://doi.org/10.1136/bmjgh-2019-001403

Su H W, et al. (2017). Detection of ovulation, a review of currently available methods. https://doi.org/10.1002/btm2.10058

Direito A, et al. (2012). Relationships between the luteinizing hormone surge and other characteristics of the menstrual cycle in normally ovulating women. https://doi.org/10.1016/j.fertnstert.2012.08.047

Cole L A, (2010). Biological functions of hCG and hCG-related molecules. https://doi.org/10.1186/1477-7827-8-102

Park S J, et al. (2007). Characteristics of the urinary luteinizing hormone surge in young ovulatory women. https://doi.org/10.1016/j.fertnstert.2007.01.045


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