Q: Good day Doc I would like to know. What is the cause of blood always reading positive to pregnancy but urine doesn’t test positive? Looking forward to your response.

A:  When pregnancy tests are done, they usually test for the presence of the hormone, Human Chorionic Gonadotrophin (hCG). The presence of this hormone signifies pregnancy and its absence denotes no pregnancy.  

Blood pregnancy tests are typically very accurate.

A positive result on blood pregnancy test, as I already noted above, could mean that you’re pregnant. If you’re not, then the false positive result could be due to medications like fertility medicines or some meds used for the treatment of seizures

It is also possible that one was pregnant at the time of the previous blood pregnancy test and miscarried soon after. This type of early pregnancy is referred to as a chemical pregnancy

An ectopic pregnancy, a situation in which a pregnancy implants outside of the womb (uterus), could also result in high hCG levels. It is usually discovered in the first couple of weeks of pregnancy (it would have been discovered by the 8th week of pregnancy). The patient would usually come into hospital with complaints of light abdominal bleeding, abdominal pain or cramps, extreme dizziness from the bleeding. If the tube ruptures (bursts), patient could faint from profuse bleeding into the abdomen.

When a miscarriage happens, the hCG in the body does not disappear overnight. It would usually take about four to six weeks after miscarriage for the hCG levels to return to normal. So, this could also be responsible for the positive pregnancy test you had.

Rising hCG levels could also be due to two conditions known as choriocarcinoma (in which a cancer forms in the ‘placenta’ tissues) or a molar pregnancy (in which a fertilized egg turns into a mass of cysts instead of a normal pregnancy).

So, your best option now is to see your doctor for a detailed history, examination and investigation. S/he will advise on next steps.

All the best!