<prompt> In defining General Fertility Rate, the denominator is:Population between 15 and 49 years of ageWomen between 15 and 49 years of ageMid-year populationLive births  <response>: Ans. is b i.e. Women between 15 and 49 years of ageRef Park 20the, p 419, 18the, p. 356 17the p 333General fertility rate GFR:It is the number of live births per 1000 women in the reproductive age group 15-44 or 49 years in a given year _ Number of live births in an area GFR--- Midyear female population age 15-44 or 49 in the same area in same yearAlso knowTotal fertility rate :Total fertility rate represents the average number of children a woman would have if she were to pass through her reproductive years bearing children at the same rates as the women now in each age groupThis measure gives the approximate magnitude of completed family size Gross reproduction rate GRR:Average number of girls that would be bom to a married woman if she experiences the current fertility pattern throughout her reproductive span 15-44 or 49 year assuming no mortality Net reproductive rate NRR:NRR is defined as the number of daughters a newborn girl will bear during her lifetime assuming fixed age specific fertility and mortality rates.NRR is demographic indicator, the present level of NRR in India is 1.5 1990.NRR of 1 is equivalent to attaining approximately the 2-child normThe govt, of India in 1983 adopted the policy of attaining a NRR of 1 by the year 1996 now to be achieved by 2006These types of questions where denominator is asked are one of the most often repeated questions in PG exams. These are the one of the easiest questions but quite often confusing because of the large number of statistical formulas.I have listed down most of the imp. Epidemiological formulas. Have a look at them and stress on the denominators.Birth Rate no. of live birth during the yrmid yr population x 1000Crude Death Rate no. of deaths during the yrmid yr population x1000General Fertility Rate no. of live birth during the yrmid yr female population age 15-44 x 1000General Marital Fertility Rate no. of live births during the yrmid yr married female population x 1000Case Fatality Rate No of deaths due to a dsno of cases due to the same ds x 100Maternal Mortality Rate Total no. of female deaths dt complication of pregnancy, child birth or within 42 days of delivery from puerperal causes total no. of live birth x 1000Still birth rate Foetal deaths weighing over 1000gm i.e. equivalent to 28 wks of gestationtotal live birth still births over 1000 gms x 1000Perinatal Mortality Rate Foetal deaths weighing over 1000 gms i.e. 28 wks gestation or more early neonatal death within 7 days of birthtotal no. of live birth x 1000Infant Mortality Rate No. of deaths of infants no. of live births x 1000Neonatal Mortality Rate no. of deaths of neonateNo. of live births x 1000Under 5 mortality rate or child mortality rate no. of deaths of children less than 5 yrs of age in a given yearno. of live birth x 10001-4 year mortality rate No. of deaths of children aged 1-4 yrs during a year total no. of children aged 1-4 yrs at the middle of the year x 1000 