Re: Please - I need a Dr.s imput!

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All pregnancy tests measure the presence or absence of a hormone known as Human Chorionic Gonadotropin (HCG), a hormone produced exclusively in pregnancy, and whose quantity increases as the pregnancy progresses. It starts at 0, and goes up from there. The various commercial pregnancy tests can detect HCG at different levels of sensitivity, so that one may read positive, while another may be negative on the same sample of urine, if the HCG level in that urine sample lies between the different test's sensitivities. Another confounding variable may be the ammount of HCG in a given urine sample. Concentrated urine, such as first morning urine will show positive sooner than dilute urine, because the concentration will be higher.

You may have had a "chemical pregnancy". This is technically a miscarriage, the pregnancy is so brief that only sensitive tests in a narrow window of time are able to detect it at all. There are some estimates that upwards of 50% of all pregnancies end this way, with the patient usually unaware that she was pregnant at all.

A blood test is usually more sensitive than urine tests, but only in very early pregnancies.

--
William D. McIntosh, MD, FACOG
Clarksville, TN

This is for educational purposes only.  It is not intended
 to replace consultation and examination by your physician
 or other health care provider.

• Next message: Brenda: "Changing Progesterone Levels?"
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• In reply to: Marisa: "Please - I need a Dr.s imput!"