MANAGEMENT OFPOSTTERM PREGNANCY1POSTTERM = 42 WEEKS2DEFINITION:ACOG BULLETIN 55, SEPT 2004Postterm pregnancy refers to pregnancies that extend beyond 42 weeks gestation (294 days, or estimated date of deliver (EDD) +14 days)Accurate pregnancy dating is critical to the diagnosisThe term postdates is poorly defned and should be avoidedAlthough some cases are a result of the inability to accurate defne the EDD, many cases result from a true prolongation of gestationReported frequency of postterm pregnancy is 7%3ETIOLOGIC FACTORSMost frequent cause of prolonged gestationA. Placental Sulfatase defciencyB. Error in DatingC. Fetal AnencephalyOther AssociationsMale SexGenetic PredispositionPrimiparityh/o prior postterm pregnancyWhen postterm pregnancy truly exists, the most common cause isUnknown4ASSESSMENT OF GESTATIONAL AGEAccurate dating is important for minimizing the false diagnosis of postterm pregnancyMOST RELIABLY AND ACCURATELY DETERMINED EARLY IN PREGNANCYQuestions at new ob visitWhen was the frst date of your last period?Do you have regular cycles? Approx how many days between cycles?Are you sure about the given date?Where you on any birth control when you got pregnant?When did you frst fnd out you were pregnant?5ACCURACY OF LMPThere are many inaccuracies in even the surest of LMPsRecallDelayed OvulationIrregular cyclesPredicting delivery date by ultrasound and last menstrual period in early gestation. Obstet Gynecol. 2001 Feb;97(2):189-94.The last menstrual period (LMP) was considered certain in 13,541 When ultrasound was used instead of certain LMP, the number of postterm pregnancies decreased from 10.3% to 2.7% (P