Progesterone in molar vesicle fluid and theca lutein cyst fluid.

Serum progesterone was estimated by a competitive protein-binding method in the peripheral venous blood in 12 cases of normal pregnancy at the time of delivery and in maternal venous blood, umbilical venoms, and umbilical arterial blood in another 5 cases. Progesterone concentration in the peripheral blood and in the serous fluid of molar vesicles was measured in 18 cases of hydatidiform mole. The theca lutein cyst fluid from 3 patients with hydatidiform mole was also assayed for progesterone. Umbilical cord venous blood and umbilical arterial blood showed a variable concentration of progesterone with a mean fetal-maternal progesterone ratio of 4.7 plus or minus 0.6 and a mean umbilical vein-artery progesterone ratio of 5.7 plus or minus 0.4. Serum progesterone concentration in hydatidiform mole was from 25.0 to 263.2 ng/ml with a mean plus or minus standard error of 101.7 plus or minus 15.2 ng/ml, while the corresponding mole vesicle fluid progesterone concentration ranged from 260.5 to 1842.0 ng/ml with a mean plus or minus SE of 770.9 plus or minus 87.4 ng/ml. The ratio of progesterone in vesicle fluid and in the serum was 4.0 to 52.8 (mean, 7.6). Progesterone concentrations in the theca lutein cyst fluid from 3 patients with hydatidiform mole were 25,428 ng/ml; 7,635 ng/ml; and 4,686 ng/ml. The high fetal-maternal progesterone ratio and umbilical vein-artery progesterone ratio reflect preferential progesterone transfer to the fetus and utilization by the latter. The finding in hydatidiform mole is due to the absence of the fetus and indicates that the molar trophoblast produced progesterone in significant amounts and that theca lutein cysts have a very high but variable concentration of progesterone in their fluid.