Answer to Question #107133 in Human Anatomy and Physiology for sarah

Question

a six week pregnancy cannot be very accurately confirmed using an at home pregnancy test kit. why?

Answer 1

The home pregnancy test kit works by measuring the HCG level in urine which is produced by the cells of the placenta. This test can measure the hormone level in urine at a range 20 to 50 mIU/mL. Usually, this level corresponds to approximately 4-6 weeks post-conception. Urine concentration of hCG rises exponentially in the first trimester of pregnancy. The peak is usually around 10 weeks of gestation. Also, a normal pregnancy may have low hCG levels and result in a perfectly healthy baby. However, the large range of normal hCG levels and inconsistent rates-of-rise of this hormone may not accurately confirm the pregnancy. That's why checking serum levels with ultrasound evaluation at six weeks of pregnancy is needed to improve sensitivity and specificity.