Questions in the Maternal and Child Health Forum have been answered by doctors from Henry Ford Health System.

Question Title: Can Pregnancy Tests Be Accurate Later in Pregnancy?

Forum: The Maternal and Child Health Forum
Topic: Pregnancy - Abnormal


I read on another bulletin board that after the 3rd month, the mother's placenta is done developing so that hCG level drops to 10% of the peak level for the mother and that pregnancy tests will then not be accurate.

Wouldn't there be at least enough hCG to bring up a positive on a QUALITATIVE blood test (the yes or no kind) or an EPT home test? Or does the hCG level drop to insignificant levels and pregnancy tests are then not accurate? Or does this only apply to home tests? Will a qual. blood test give a positive if a woman is 5, 6, 7 months pregnant even if her hCG levels have dropped?

One more question - how accuate is an OB-GYN's pelvic exam to determine pregnacy at 8 weeks since the actual conception date - is there anything in particular I need to be sure the OBGYN is looking for or that I need to ask.

I'm so confused and hoping you can answer my questions. Thanks.


The short answer to your question about hCG is yes, qualitative blood and urine tests will remain positive throughout pregnancy. Even though placental production of hCG is lower later in pregnancy, there still will be high enough levels (>30 mIU) to make tests positive.

Eight weeks past the conception date (or 10 weeks last menstrual period dates) should be detectable by physical exam. However, certain situations (i.e. maternal obesity) may make the physical diagnosis difficult.



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