A challenge to the concept of tubal reflux to explain the rise and fall of CA125 in serum during the first trimester.
Although amniotic fluid concentrations of cancer antigen (CA) 125 rise during the first two trimesters of pregnancy, the serum concentrations of CA125 peak during the first trimester and drop to non-pregnant values in the second and third trimester. A previous hypothesis to explain this phenomenon was that in the early first trimester decidual CA125 gains access to the maternal compartment via 'tubal reflux' and subsequent absorption by peritoneal lymphatics. However, as pregnancy advances, the decidua capsularis fuses with the decidua parietalis, thus obliterating the endometrial cavity at 10-12 weeks; the Fallopian tubes thus become functionally obstructed. To test this hypothesis, we evaluated early first trimester CA125 concentrations in women conceiving by in-vitro fertilization (IVF) and embryo transfer with patent tubes (group 1) and in those conceiving by IVF and embryo transfer with bilateral tubal occlusion (group 2). We also compared those conceiving with human menopausal gonadotrophin therapy for ovulation induction without assisted reproduction (group 3) and those conceiving without fertility drugs in assisted reproduction (group 4). Mean CA125 concentrations were similar in groups 1-3; the mean CA125 concentration in group 4 was lower but this difference was not statistically significant, probably due to the small sample size. These data do not support the concept that tubal reflux explains the rise and fall of serum concentrations of CA125, since these were equal in IVF conceptions with or without tubal patency.
Check
J H
JH
University of Medicine and Dentistry of New Jersey/Robert Wood Johnson Medical School at Camden, Cooper Hospital/University Medical Center, Department of Obstetrics and Gynecology, USA.
Vetter
B H
BH
D018394:CA-125 Antigen / Q000097:blood*; D003656:Decidua / Q000378:metabolism; D004624:Embryo Transfer; D005184:Fallopian Tube Diseases / Q000097:blood; D005187:Fallopian Tubes / Q000378:metabolism*; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D008596:Menotropins / Q000627:therapeutic use; D010062:Ovulation Induction; D011247:Pregnancy / Q000097:blood*
D018394:CA-125 Antigen; D008596:Menotropins