faint line on ovulation test could i be pregnant?

How to Read Ovulation Test Lines
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July 2, 2022
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 are readily available and less intrusive than other methods (i.e. transvaginal sonography).

Ovulation test strips work by detecting a hormone called luteinizing hormone (LH) in the urine which rapidly increases (or surges) approximately 35 to 44 hours before ovulation.

Similar to other at-home hormone tests, ovulation test strips feature 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.
Only One Line On Ovulation Test

Only one line (i.e. no second line) on the ovulation test happens if you test too early or too late in 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.

It is also normal for women to experience an anovulatory cycle once in a while, meaning no LH surge. However if this continues for a few months, please consult a medical professional.
Faint Line on Ovulation Test

A faint line on an ovulation test means your LH levels are currently below the LH threshold defined as a positive result.

Similarly, a faint line on an ovulation test after ovulation and before your period means your LH levels have dropped below the LH threshold set for a positive result.

Lastly, a faint line on an ovulation test does not imply you are pregnant.

Only two solid lines on an ovulation test, approximately 2 weeks after ovulation, 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.
Do Ovulation Sticks Get Darker The Closer To Ovulation

Yes, the second line on an ovulation test (stick) becomes darker the closer a woman is to ovulation. This is because the levels of LH in your urine increases daily as you near the day of ovulation.

The day (or two) before ovulation, LH levels rise dramatically otherwise known as an LH surge. This means the second line on an ovulation test stick will become darker than the control line, and continue to be darker than the control line on the actual day of ovulation.
Two Lines On Ovulation Test

Two lines on an ovulation test indicates your LH levels is near or equal to the LH threshold set by the manufacturer on the control line.

However, this can mean a number of things depending on the colour of the 2 lines and which cycle day you did the test.

For example, two lines on an ovulation test, with one line (test line) lighter than the other (control line) before ovulation means your LH levels is nearing the LH threshold set for a positive result.

Alternatively, after ovulation, one line (test line) lighter than the other (control line) on an ovulation test, means your LH levels are declining back to baseline.

Finally, an ovulation test with two matching lines is a positive result indicating an LH surge.
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.
Three Lines On Ovulation Test

Three lines on an ovulation test is considered invalid due to poor manufacturing (i.e. defective).

Irrespective if you did the test during your fertile window (for LH), or outside your fertile window (for HCG).

You will have to do the test again to get an accurate result.
No Line On Ovulation Test

No control and test line on an ovulation test means the absorbent tip wasn’t saturated with enough urine, you have a rare condition, the ovulation test is defective or has expired.

Therefore, an ovulation test with no lines does not suggest you are pregnant.

Fortunately in the majority of cases, no lines on an ovulation test means the test is defective (or you have a rare condition). This is easy to check by doing the test again.

You can also ask your partner do the test (as males have the same hormone) to confirm you have a faulty batch of OPKs.
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 distinguish between the two hormones.

In fact, the majority of ovulation tests use a LH test threshold of 25 mIU/ml. This means in theory ovulation tests could 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 confirm you are pregnant.
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.

Read More:

What A Positive Then Negative Ovulation Test Means | Fertility SCIENCE

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

However, on their own OPKs are not a miracle treatment and do not decrease the time-to-pregnancy significantly. This is because there are many others factors which contribute to successful conception other than timed intercourse.

On the other hand, ovulation predictor kits (OPKs) allow women to understand their cycles better and seek medical assistance earlier (if required), which does indirectly decrease the time-to-pregnancy.

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