<prompt> Investigation of Choice post datism?USGXrayAmniocentesisSpectrophotometry  <response>: ANSWER: A USGREF: Dutta 6th edp. 319Post dated pregnancy: 2weeks beyond the expected date of delivery gestational age 294 daysEtiology:Wrong dates : most commonHereditaryPrimi, sedentary habit, previous prolonged pregnancy, elderly multiparaFetal congenital anomalies like anencephalyPlacental sulphatase deficiencyClinical diagnosis:Menstrual historyWeight recordAbdominal girthHeight of uterus , uterus feels full of fetus , hard bones of fetusRipe cervixInvestigations:Assessment of fetal maturity:? USG: it is the investigation of choice? FL, CRL, BPD are measured and composite biometry done? Amniocentesis is invasive, and has been replaced by USG.Assessment of well being:? Modified biophysical profile? Absence of umbilical artery end diastolic frequency indicates fetal jeopardy. 