POSTTERM PREGNANCYPOSTTERM PREGNANCY

AZZA ALYAMANIAZZA ALYAMANI

OBSTETRICS & GYNICOLOGYOBSTETRICS & GYNICOLOGY

DepartmentDepartment

King Khalid UniversityKing Khalid University

IntroductionIntroduction

Post term pregnancy is a common situation. It Post term pregnancy is a common situation. It

cause cause anxietyanxiety for both women and obstetricians for both women and obstetricians

because it perceived as being a cause of increased because it perceived as being a cause of increased

risk to the fetus.risk to the fetus.

Post term pregnancy per se is not a pathological Post term pregnancy per se is not a pathological

condition and should not be confused with thecondition and should not be confused with the

post maturity syndrome post maturity syndrome described by Clifford indescribed by Clifford in

1954.1954.

DefinitionsDefinitions

* Post term* Post term ( prolonged pregnancy ) : ( prolonged pregnancy ) : it is it is 42 completed weeks or more 42 completed weeks or more ( 294 days).( 294 days). this definition is accepted by both WHO & FIGO.this definition is accepted by both WHO & FIGO.

* Post maturity* Post maturity syndromesyndrome : : it is it is IUGRIUGR with associations of ,meconium with associations of ,meconium stained amniotic fluid , oligohydramnios , fetalstained amniotic fluid , oligohydramnios , fetal distress , loss of subcutaneous fat and dry distress , loss of subcutaneous fat and dry cracked skin reflecting cracked skin reflecting placental insufficiencyplacental insufficiency..

* Past date* Past date : : past the calculated EDD before 42 weeks.past the calculated EDD before 42 weeks.

Incidence :Incidence :

5 -10 % 5 -10 %

Dating by the last menstrual period (LMP) alone ,Dating by the last menstrual period (LMP) alone ,

has a tendency to overestimate the GA .has a tendency to overestimate the GA .

While the use of early ultrasound alone , to calculateWhile the use of early ultrasound alone , to calculate

GA , significantly reduced the incidence of post term GA , significantly reduced the incidence of post term

pregnancy .pregnancy . Ia Ia

ImportanceImportance A)A) Fetal and Neonatal risksFetal and Neonatal risks

* * It is likely that the majority of morbidity It is likely that the majority of morbidity and mortality associated with post term and mortality associated with post term pregnancy, arises because of pregnancy, arises because of post maturitypost maturity..

** Post term pregnancies are associated Post term pregnancies are associated with excess with excess perinatal morbidity & mortality perinatal morbidity & mortality . .

** Delivery at 42 week is associated with a Delivery at 42 week is associated with a doublingdoubling of the perinatal mortality rate , unlike of the perinatal mortality rate , unlike

the 37 -41 week period in which the 37 -41 week period in which antepartumantepartum

deathsdeaths contribute about 2/3 of the total . contribute about 2/3 of the total .

When lethal congenital abnormalities areWhen lethal congenital abnormalities are

excluded ,excluded ,intrapartum fetal deathintrapartum fetal death is is 4 times4 times more more

common, andcommon, and

neonatal deathneonatal death is is 3 times3 times more common in infant more common in infant s s born after 42 weeks.born after 42 weeks.

In addition , In addition , meconium stainingmeconium staining of the amniotic of the amniotic

fluid and the likely of fluid and the likely of intrapartum fetal hypoxiaintrapartum fetal hypoxia

were much more common in post term were much more common in post term

pregnancies compared to those delivered at 40 ws.pregnancies compared to those delivered at 40 ws.

This result in This result in fetal acidosisfetal acidosis , , neonatal seizuresneonatal seizures & &

perinatal deathperinatal death . Post term pregnancy is also a . Post term pregnancy is also a

risk factor for risk factor for birth traumabirth trauma and and shoulder dystociashoulder dystocia..

B)B) Maternal risks of post term pregnanciesMaternal risks of post term pregnancies::

** increased increased operativeoperative delivery , delivery , hemorrhagehemorrhage and and

maternal maternal infectioninfection..

** in addition , psychological morbidity as in addition , psychological morbidity as

increased maternal increased maternal anxietyanxiety . .

EtiologyEtiology

Not ClearNot ClearIt is common in :It is common in : * primigravida* primigravida * previous post term pregnancy. 30%* previous post term pregnancy. 30%

The causeThe cause may be due tomay be due to : : 1. low cortisol levels with post term fetal distress.1. low cortisol levels with post term fetal distress. 2. relative 2. relative adrenocortical insufficiency adrenocortical insufficiency leading to leading to delay in the onset of labor & increased risk of delay in the onset of labor & increased risk of intrapartum hypoxia or death.intrapartum hypoxia or death.

Support for this theory is thatSupport for this theory is that : :

infants delivered following a post term pregnancies infants delivered following a post term pregnancies

are at increased risk of :are at increased risk of :

** sudden infant death syndrome. sudden infant death syndrome.

* * death up to 2 years of age.death up to 2 years of age.

Fetal AssessmentFetal Assessment

Monitoring Post term PregnancyMonitoring Post term Pregnancy

The perinatal mortality does not significantly rise The perinatal mortality does not significantly rise

until 42 ws. gestation ,thus there is until 42 ws. gestation ,thus there is no needno need to offer to offer

fetal monitoring prior to this gestation, if it is notfetal monitoring prior to this gestation, if it is not

offered at term .offered at term .

There is There is no consensusno consensus about the appropriate about the appropriate

surveillance to post term pregnancy and surveillance to post term pregnancy and no clearno clear

evidence exists to support that fetal monitoringevidence exists to support that fetal monitoring

can reduce the perinatal mortality.can reduce the perinatal mortality.

* * simplesimple fetal monitoring fetal monitoring is is as effective asas effective as more more

sophisticated monitoring of post term pregnanciessophisticated monitoring of post term pregnancies

* The use of * The use of Doppler analysisDoppler analysis of various arterial of various arterial

systems as uterine , umbilical ,middle cerebral systems as uterine , umbilical ,middle cerebral

and descending aorta in uncomplicated post termand descending aorta in uncomplicated post term

pregnancies is pregnancies is notnot different from that in term different from that in term

pregnancies.pregnancies.

ThereforeTherefore

the recommended fetal monitoring the recommended fetal monitoring

in post term pregnancy in post term pregnancy

isis

a) a) Amniotic fluid measurementAmniotic fluid measurement

Liquor volume fall after term , thus AFI doesLiquor volume fall after term , thus AFI does

not improve perinatal outcomes , thus the meannot improve perinatal outcomes , thus the mean

pool depth pool depth (MPD)(MPD) is the tool of choice is the tool of choice for monitoring for monitoring

liquor in post term pregnancy. liquor in post term pregnancy. Ib Ib

b)b) CTG CTG

Simple monitoring with Simple monitoring with NSTNST and and liquor liquor assessment holds an advantage over the formalassessment holds an advantage over the formal

biophysical profile scoring.biophysical profile scoring.

It is therefore ,vital that each woman is treated It is therefore ,vital that each woman is treated

on an individual basis and counseled regarding on an individual basis and counseled regarding

the risks of post term pregnancy. the risks of post term pregnancy.

ManagementManagement

(1) induction of labor at 41+ weeks(1) induction of labor at 41+ weeks

to reduce perinatal mortality , meconium staining to reduce perinatal mortality , meconium staining of the amniotic fluid and small decrease inof the amniotic fluid and small decrease in caesarean section rate . caesarean section rate . 1a1a

(2) conservative management(2) conservative management

with close fetal surveillance, this can reducewith close fetal surveillance, this can reduce excess operative delivery in women who willexcess operative delivery in women who will opt to for conservative management .opt to for conservative management .

Other interventionsOther interventions::

a.a. nipple stimulationnipple stimulation

but have not been shown to be of benefit . but have not been shown to be of benefit .

b.b. sweeping the membranessweeping the membranes

at or beyond 40 weeks appear to significantlyat or beyond 40 weeks appear to significantly

reduce the incidence of post term pregnancyreduce the incidence of post term pregnancy

and should be offered to all women. and should be offered to all women.

Key pointsKey points::

1. the use of 1. the use of early ultrasound dating early ultrasound dating , reduces the, reduces the

incidence of postterm pregnancy.incidence of postterm pregnancy.

2. 2. induction of labor after 41+ weeksinduction of labor after 41+ weeks reduces perinatal reduces perinatal

mortality rates without increasing CS rates.mortality rates without increasing CS rates.

3. sweeping the membranes significantly reduces the 3. sweeping the membranes significantly reduces the

incidence of postterm pregnancy .incidence of postterm pregnancy .

4. no clear evidence that fetal monitoring can reduce the 4. no clear evidence that fetal monitoring can reduce the

perinatal mortality in postterm pregnancy.perinatal mortality in postterm pregnancy.

5. the use of 5. the use of NST NST andand liquor assessment liquor assessment in monitoringin monitoring

postterm pregnancy twice weekly is recommended inpostterm pregnancy twice weekly is recommended in

women who prefer conservative management withwomen who prefer conservative management with

fetal surveillance.fetal surveillance.

THANK YOUTHANK YOU