During pregnancy, maximum urinary HCG level is reached in: March 2007

Ans. C: 70 days Human chorionic gonadotropin (hCG) is made by the embryo soon after conception and later by the syncytiotrophoblast. It can be detected as early as 8-9 days following ovulation, doubles every 2 days in pregnancy and maximum levels are reached between 60-70 days of pregnancy (100-200 IU/ ml) Its role is to prevent the disintegration of the corpus luteum of the ovary and thereby maintain progesterone production that is critical for a pregnancy in humans. Early pregnancy testing, in general, is based on the detection or measurement of hCG. It is an impoant tumor marker. The beta subunit of human chorionic gonadotropin is secreted also by choriocarcinoma, germ cell tumors, teratoma and islet cell tumor. The lack of a visible fetus on vaginal ultrasound after the beta hCG levels have reached 1500 IU/ ml is strongly indicative of an ectopic pregnancy. Gestational trophoblastic disease like Hydatidiform moles ("molar pregnancy") or Chroiocarcinoma may produce high levels of beta hCG (due to the presence of syncytialtrophoblasts- pa of the villi that make up the placenta) despite the absence of an embryo.