Doubling of Beta HCG levels is seen in?

Ans. (b) 48 hoursRef.: D.C. Dutta 8th ed. /23, 8th ed. / 66, 7h ed./58-59HCG* HCG is a glycoprotein which is synthesized by syncytiotrophoblast of the placenta.* The half-life of HCG is 36 hours.* In early pregnancy the doubling time of HCG is 1.4 -2days.* It has 2 subunits:# a-biologically similar in LH, FSH and TSH. (i.e. nonspecific)# b-subunit-unique to HCG. (i.e. specific)* Structurally it is similar to- FSH, LH, TSH but functionally it is similar to LH (i.e. luteotropic), i.e. helps in maintaining corpus luteum. So, the main hormone which maintains activity of corpus luteum during pregnancy is HCG and in non-pregnant state is LH.* It can be detected in material serum as early as 8 days following fertilization/day 22 of menstrual cycle/5 days before missed period by immuno assay.0* The level is 100 IU/L or mlU/mL around the time of the expected menses.* The level progressively rise and reach maximum levels by about 8-10 weeks/70days/lst trimester. It then falls until about 16 weeks and remains at low level up to term.* HCG disappears from circulation by 2 weeks following delivery.Action* Sustains the corpus luteum and thereby maintains the hormonal support to the pregnancy in early weeks.* Stimulates the leydig cells of the male fetus to produce testosterone and thereby induces development of the male external genitalia