Question

1. A woman that is at risk of having a non-viable pregnancy may have to have blood draws frequently (every several days) at the beginning of her pregnancy to check for hormone levels. What hormone do you think is most likely being checked for, why? Draw a graph showing what normal levels of this hormone would look like and what hormones of a non-viable or at-risk pregnancy might look like.

Answer 1

Human chorionic gonadotropin or hCG is the hormone produced by the placenta, which enters the maternal circulation and is seen in urine. Pregnancy is detected by urine hCG test. However, when there is threat of a non-viable pregnancy, its levels fluctuate in blood. Hence, frequent hCG blood test need to be performed to detect whether the mother is at risk of miscarriage. Blood test for hCG involves removal of blood sample by venous puncture. The hCG levels normally double and increase as the pregnancy proceeds. However, if there is a risk of non-viable pregnancy, then the hCG levels do not double in blood every 48-72hrs, then it is deemed that there is a risk of non-viable pregnancy. In case of miscarriage, the hCG levels will drop instead of increasing. The hCG levels along with progesterone levels will be most beneficial in detecting non-viable pregnancies.

hCG levels increase to high levels in first trimester and after that they decline and remain stable for rest of pregnancy. This is not observed in a threatened non-viable pregnancy as shown in the graph. The graph shows hCG levels in blood on Y-axis and weeks of pregnancy on X-axis. As seen, in normal pregnancy, the hCG levels increase, doubly every week and then come back to a table level. In threatened non-viable pregnancy, hCG levels do not double as seen in normal pregnancy and the levels are also low. The graph only shows the trend in hCG levels.

250000 225000 200000 175000 hCG Levels 10/mL 125000 10000 Normal Pregnancy 75000 50000 Threatened Non-viable Pregnancy 25000 2 4 6 8 10 12 14 16 18 20 22 24 Time of Pregnancy (weeks)