Postterm PregnancyIGUBAN, MAJOERIE S.

Postterm pregnancy 42 completed weeks (294 days) or more from the first day of the last menstrual period

Estimated Gestational Age using Menstrual Dates2 categories:Those truly 40 weeks past conceptionThose of less advanced gestation but with inaccurately estimated gestational age

Sonographic evaluation of gestational age has been used to add precision

Incidence4-19% according to Divon and Feldman-Leidner (2008)2000: 7.2% vs 2006: 5.6%

Risk factor:BMI 25 and Nulliparity (1998 to 2001 Danish Birth Cohort)

Repeated postterm births: incidence of subsequent postterm birth increased from 10 to 27% if the first birth was postterm. (Bakketeig and Bergsjo, 1991)Increased to 39% if there had been 2 previous, successive postterm births

Perinatal mortalityIncreased perinatal mortality after the expected due date was passed.Major causes: gestational hypertensionProlonged labor with CPDunexplained anoxiaMalformationsIncreased rate of cesarean delivery for dystocia and fetal distress

Pathophysiologypostmature or postmaturity syndromeWrinkled, patchy, peeling skinLong, thin body suggesting wastingAdvanced maturity (open-eyed, unusually alert, appeard old and worried)Nails typically long

Associated oligohydramnios

Placental dysfunctionSkin changes were due to loss of protective effects of vernix caseosaPlacental senescencePlacental insufficiency (Larsen and co-workers, 1995)Placental apoptosis (Smith and Baker, 1999)

Erythropoietin levels significantly increase in pregnancies reaching 41 weeks or moreDecreased fetal oxygenation

Fetal distress and oligohydramniosLeveno and associates (1984): both antepartum fetal jeopardy and intrapartum fetal distress were the consequences of cord compression associated with oligohydramnios

Amniotic fluid volume continues to decrease after 38 weeks

ComplicationsOligohydramniosMacrosomiaMedical or Obstetrical Complications

ManagementInduced laborPrognostic factors for successful inductionUnfavorable cervixCervical ripeningStation of Vertex

Recommendations:Inititation of fetal surveillance at 41 weeks. After completing 42 weeks, either antenatal testing or labor induction (American College of Obstetricians and Gynecologists)Labor induction (Parkland Hospital)

Intrapartum ManagementWhile being evaluated for active labor, fetal heart rate and uterine contractions be monitored electronically for variations consistent with fetal compromise (American College of Obstetricians and Gynecologists)

Fetal Growth Disorders

Normal Fetal growthFetal growth characterized by sequential patterns of tissue and organ growth, differentiation, and maturation.

3 consecutive phases of cell growth:Initial phase of hyperplasia: 1st 16 weeks; rapid increase in cell numberCellular hyperplasia and hypertrophy: up to 32 weeksCellular hypertrophy: after 32 weeks; most fetal fat and glycogen deposition

Fetal growth restrictionLow-birthweight infants who are small-for-gestational age

Small-for-gestational ageWeight is below the 10th percentile for their gestational age (Battaglia and Lubchenco (1967)Mean weights-for-age with normal limits defined by 2 standard deviations ( Usher and McLean, 1969)

Metabolic abnormalitiesMajor cause of hypoglycemia in SGA fetuses was reduced supply rather than increased fetal consumption or diminished fetal glucose production. These fetuses had hypoinsulinemia along with hypoglycemia (Economides and co-workers, 1989)Glycine:Valine ratio in cord blood from growth-restricted fetuses and found ratios similar to those observed in older children with kwashiorkorHypertrigyceridemia correlated with degree of fetal hypoxemia

Morbidity and MortalityIncreased rate of:Fetal demiseBirth asphyxiaMeconium aspirationNeonatal hypoglycemiaHypothermia

Risk FactorsConstitutionally small mothersPoor maternal nutritionSocial deprivationMaternal and fetal infectionsCongenital malformationsChromosomal aneuploidiesDisorders of cartilage and boneDrugs with teratogenic and fetal effectsVascular diseaseRenal diseasePregestational diabetesChronic hypoxiaAnemiaPlacental and cord abnormalitiesInfertilityExtrauterine pregnancyAntiphospholipid Antibody SyndromeGeneticsMultiple fetuses

Identification of Fetal-Growth RestrictionUterine Fundal heightSonographic measurementsAmniotic fluid measurementDoppler velocimetry

PreventionOptimization of maternal medical conditions, medications, and nutritionAccurate pregnancy dating is essential

ManagementGrowth restriction near termPrompt delivery

Growth Restriction remote from termObservation

Long term sequelaeAdult hypertension and atherosclerosisDevelopment of type-2 diabetesHeart disease both in the mother and fetus

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