(prolonged)Post-termpregnancy
Post-term（prolonged） pregnancy
definitionPost-term pregnancy, extends beyond 294 daysor 42 weeks from the first dayof theLMP.Increased perinatal morbidity and mortality havebeen documented when pregnancy extendsbeyond 42 weeks' gestation. The incidence ofcongenital anomalies is also increased inpostdatepregnancies
definition ◼ Post-term pregnancy, extends beyond 294 days or 42 weeks from the first day of the LMP. Increased perinatal morbidity and mortality have been documented when pregnancy extends beyond 42 weeks' gestation. The incidence of congenital anomalies is also increased in postdate pregnancies
EpidemiologyTheincidenceof posttermpregnancy rangesbetween 7%and 12%ofallpregnancies.Approximately 4% of all pregnancies extendbeyond 43weeks,and recurrence riskis50%forsubsequentpregnancies
Epidemiology. ◼ The incidence of postterm pregnancy ranges between 7% and 12% of all pregnancies. Approximately 4% of all pregnancies extend beyond 43 weeks, and recurrence risk is 50% for subsequent pregnancies
Diagnosis1.post-term pregnancy must be based on anaccurate estimate of gestational age. 2.Obstetric dates should be considered valid iftwo or more of the following criteria are met:certain LMP; positive urine pregnancy test 6weeksfromtheLMP:
Diagnosis ◼ 1.post-term pregnancy must be based on an accurate estimate of gestational age. ◼ 2.Obstetric dates should be considered valid if two or more of the following criteria are met: certain LMP; positive urine pregnancy test 6 weeks from the LMP;
3.fetal heart tone detected with Dopplerultrasonographic testing at 10 to 12 weeks'gestation orwith DeLee's stethoscope at 18 to 20 weeks'gestation;fundal height at the umbilicus at 20 weeks'gestation;pelvic examination consistent with LMP before 13weeks'gestation; and ultrasonographic dating by lengthbetween 6 and 12 weeks'gestation or by biparietaldiameter before 26 weeks'gestation.The best estimates of gestational age are based on asmany criteriaas possible
◼ 3.fetal heart tone detected with Doppler ultrasonographic testing at 10 to 12 weeks' gestation or with DeLee's stethoscope at 18 to 20 weeks' gestation; fundal height at the umbilicus at 20 weeks' gestation; pelvic examination consistent with LMP before 13 weeks' gestation; and ultrasonographic dating by length between 6 and 12 weeks' gestation or by biparietal diameter before 26 weeks' gestation. ◼ The best estimates of gestational age are based on as many criteria as possible
Complications1.Postmature or dysmature neonates exhibit someof the following findings: wasting ofsubcutaneoustissue,failure of intrauterinegrowth, meconium staining, dehydration (脱水），absenceofvernixcaseosa胎儿皮脂andlanugo胎毛hair，oligohydramnios,andpeeling脱皮 of skin.Such findings are describedinapproximately 10% to 20% of true posttermfetuses
Complications 1.Postmature or dysmature neonates exhibit some of the following findings: wasting of subcutaneous tissue, failure of intrauterine growth, meconium staining, dehydration（脱 水）, absence of vernix caseosa胎儿皮脂 and lanugo胎毛 hair, oligohydramnios, and peeling 脱 皮 of skin. Such findings are described in approximately 10% to 20% of true postterm fetuses
2.MacrosomiaMacrosomia is far more common in posttermthan term pregnancies. Twice as many posttermfetuses than term fetuses weigh more than 4,000g.Birth injuries caused by difficult deliveries andshoulderdystociaare increased inposttermpregnancy
◼ 2. Macrosomia ◼ Macrosomia is far more common in postterm than term pregnancies. Twice as many postterm fetuses than term fetuses weigh more than 4,000 g. Birth injuries caused by difficult deliveries and shoulder dystocia are increased in postterm pregnancy
Oligohydramnios. Amniotic fluid tends to decrease inpostterm gestation, probably due to decreasinguteroplacental reserve.Low AFV is associated withincreased rates of intrapartum fetaldistress andcesareandeliveryMeconium.Postterm gestations report an increasedincidence of meconium-stained amniotic fluid andmeconiumaspirationsyndrome
◼ Oligohydramnios. Amniotic fluid tends to decrease in postterm gestation, probably due to decreasing uteroplacental reserve. Low AFV is associated with increased rates of intrapartum fetal distress and cesarean delivery. ◼ Meconium. Postterm gestations report an increased incidence of meconium-stained amniotic fluid and meconium aspiration syndrome
Management.After 40 weeks'gestation,patients maykeepdailyfetalmovement charts. Many physicians generally accept thatcareful fetal monitoring can reduce the risk of perinatalmortality of the postterm fetus to virtually that of theterm fetus, but which method is best remainscontroversial. Whether the patient who reaches 41 to42 weeks'gestation with an unripe cervix is bettermanaged by cervical ripening and induction or bycontinued testing is under debate
Management. ◼ After 40 weeks' gestation, patients may keep daily fetal movement charts. Many physicians generally accept that careful fetal monitoring can reduce the risk of perinatal mortality of the postterm fetus to virtually that of the term fetus, but which method is best remains controversial. Whether the patient who reaches 41 to 42 weeks' gestation with an unripe cervix is better managed by cervical ripening and induction or by continued testing is under debate
Antepartum Testing.The use of the NST as asingle technique to evaluate the posttermgestation is not recommended, based on reportsof poor outcome after a reactive nonstress testin this situation. However, evidence suggeststhat semi-weekly NSTs in combination withAFIs can reduce perinatal mortality (18)
◼ Antepartum Testing. The use of the NST as a single technique to evaluate the postterm gestation is not recommended, based on reports of poor outcome after a reactive nonstress test in this situation. However, evidence suggests that semi-weekly NSTs in combination with AFIs can reduce perinatal mortality (18)