The relation between depth of trophoblastic invasion and β-HCG levels in tubal pregnancies
Ectopic implantation usually begins with relatively normal growth of trophoblast and serum beta-hCG progression. However, the trophoblast eventually erodes into vessels and a variable degree of bleeding and hematoma compromises its growth. The serum beta-hCG level then usually begins to demonstrate some degree of abnormal progression. For our patients, the length of the ectopic pregnancy varied widely, depending mainly on when the individual patient chose to seek medical treatment. Infertility patients followed from the moment of conception would thus be expected to show a better correlation between early beta-hCG levels and the size of the tubal pregnancy. Preconditions for the operative laparoscopic management of a tubal pregnancy usually include that the tube be unruptured, less than 3 cm in diameter, and readily accessible via the laparoscopic approach. Ackerman et al. suggested there was a general correlation between the serum beta-hCG level and tubal rupture, and the present data demonstrate an overall positive correlation between the size of the tubal pregnancy and the serum level. However, the range of levels is so broad for any given size of mass or tubal status that this correlation is not meaningful clinically. A reliable method to determine the size and status of a tubal pregnancy before laparoscopy would be valuable. Unfortunately, we did not find the preoperative serum beta-hCG level to be useful for making this prediction.