A 20 weeks pregnant woman is referred to your office with newly diagnosed hypeension. You are concerned that the fetus and placenta may be compromised. To assess fetal and placental health, which of the following hormone measurements would be most informative?

Serum hCG is produced by the syncytiotrophoblast and released into the fetal and maternal circulation. It is known as the hormone of pregnancy and is the basis for the pregnancy test. hCG is detected in serum at day 6-8 after implantation, and its levels peak at 60-90 days of gestation, declining thereafter. Maternal hCG levels are a useful index of functional status of the trophoblast (placental health). The main source of estrogen during the initial phase of pregnancy is the corpus luteum, being replaced later by placental production. The principal estrogen produced by the syncytiotrophoblast cells of the placenta is estriol. Plasma and urinary levels of estriol increase significantly throughout pregnancy to about 25 ng/mL during the last trimester. So Maternal hCG and Urinary estriol hormone measurement would be most informative to assess fetal and placental health. Ref: Molina P.E. (2010). Chapter 9. Female Reproductive System. In P.E. Molina (Ed), Endocrine Physiology, 3e.