Are you a series POASer....? Even after you get the double line?

Is a Lighter Colored Home Pregnancy Test Line a Sign of Miscarriage?
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By Krissi Danielsson, Miscarriage/Pregnancy Loss Expert
Updated November 25, 2014.

Question: Is a Lighter Colored Home Pregnancy Test Line a Sign of Miscarriage?

Home pregnancy test lines show up -- or don't -- based on the detection of the hormone hCG in your urine. When hCG is present, the test will return a positive result for pregnancy, and when hCG is not present, the test comes back negative. Given that hCG levels increase exponentially during early pregnancy, doesn't that mean the pregnancy test line should get darker and darker if the pregnancy is normal?


Answer:

In actuality, things are not that simple. Although a home pregnancy test line would probably be darker when the urine has a higher concentration of hCG, taking multiple home pregnancy tests to check the color of the line is simply not a reliable method of monitoring development of early pregnancy. Blood is the far more reliable body fluid for monitoring hCG levels.

The reason is that blood maintains a fairly steady composition at all times, thus making it easier to monitor changes in chemicals such as hCG. In contrast, the concentration of urine will fluctuate heavily throughout the day based on how much fluid you drink, how frequently you use the restroom, and other factors. Less concentrated urine means a lighter colored home pregnancy test line.

See Also: The Right Way to Take a Pregnancy Test

Even though you will likely pass more hCG in your urine during the course of a day as the pregnancy progresses and your levels increase, this does not mean a home pregnancy test would necessarily reveal a darker line. A person in early pregnancy who takes a test with very concentrated urine could theoretically have a darker colored home pregnancy test line than someone in later pregnancy who tests after drinking multiple gallons of water.

In contrast, the levels of hCG in your blood would not be affected by external factors, and thus quantitative hCG blood tests over a period of days are far more reliable for monitoring hCG levels.

If you are feeling anxious about miscarriage or having any symptoms, don't waste money buying multiple home pregnancy tests (and if you can't fight the temptation, don't waste time worrying about light-colored pregnancy test lines). Instead, speak to a practitioner about finding some other form of reassurance that your pregnancy is progressing as it should, such as a blood test.

Source:

Bastian, Lori A., Kavita Nanda, Vic Hasselblad, and David Simel, "Diagnostic Efficiency of Home Pregnancy Tests." Archives of Family Medicine Sept 1998. Accessed 23 Jul 2008.

Perfect timing Myturn. I got a BFP a few days ago and have been obsessively poasing to make sure the line is getting darker :)

I am not obsessed in the least. I wait to POAS until atleast a few days after my period was due. I have never had a dark line either. The line came up quickly with this pregnancy but it was not dark at all. I only drink water and a coffee in the morning and tea in the afternoon. The test was at night time. I wonder if only drinking water is the reason I only had light lines. It has never made me worry that I might MC though.