Maternal serum CA125 levels in early intrauterine and tubal pregnancies.

Using an immunoradiometric assay, serum CA125 levels were measured in 13 women with a normal pregnancy, 9 with a spontaneous abortion, 3 with a hydatidiform mole, and 15 with a tubal pregnancy. Serum CA125 levels were high in patients with a normal pregnancy (154 +/- 169 U/ml; mean +/- S.D.), a spontaneous abortion (244 +/- 258 U/ml), or a hydatidiform mole (54 +/- 16 U/ml). In contrast, CA125 levels in patients with a tubal pregnancy (33 +/- 25 U/ml) were low, and almost all of those without uterine bleeding (25 +/- 9 U/ml) were within the normal range for non-pregnant women (< 35 U/ml). The difference between serum CA125 levels with intrauterine pregnancy and with tubal pregnancy may be ascribed to the difference of the amount of decidual tissues at the site of trophoblastic invasion.