A pregnant woman is found to have excessive accumulation of amniotic fluid. Such polyhdramnios is likely to be associated with all of the following conditions, except;

Ans. is 'd' i.e. Bilateral renal agenesisRef Repeat, Dutta Obs. 6th/e, p 214 (5th/e, p225)Etiology of polyhydramniosFetal anomalies - (About 20% of cases)Anencephaly - About 50% of casesOpen spina bifidaOesophageal or Duodenal atresiaFetal clefts and neck massesHydrops fetalis due to Rh iso immunizationPlacentalChoriocarcinoma of the placentaMultiple pregnancyHydramnios is more common in uniovular twins, usually affecting the second sac.MaternalDiabetes (50% cases have polyhydramnios)Renal or Cardiac abnormalitiesAlso rememberNormal volume of liquor at 10 weeks- 30 ml20 weeks- 250 ml 30 - 40 weeks - 500 - 1500 mlPolyhydramnios: when amniotic fluid is > 2000 ml.OligohydramniosWhen amniotic fluid < 100 mlSonographic diagnosis is made when amniotic fluid index is 5 cm or lessCauses of oligohydramniosAmnion nodosum - failure of secretion by the cells of amnion covering the placentaRenal agenesis or obstruction of the urinary tract 1UGR associated with placental insufficiencyAffecting one sac of uniovular twin, with an excess of fluid in the otherPostmaturity (dysmaturity)