prolonged pregnancy

Definition: is any pregnancy last for 42 weeks or more (294) days or more.

It s a cause of anxiety for both woman &obstetrician & should be differentiated from IUGR.
Fetal risk of post term pregnancy are:

1.fetal hypoxia& acidosis
2.neonatal seizure &Perinatal death..
3.macrosomia &need for ClS also increase.
4. shoulder dystocia &birth trauma.
5.muconium stain syndrome.
6. sudden infant death syndrome.
7.increase Perinatal mortality morbidity.
8.fetal trauma may lead to cerebral pulsy&IVH

Maternal risks of post term pregnancy:

1.increase operative delivery.
2.increase bleeding &postpartum hemorrhage
3.increase incidence of prolonged labour with it s complication like fetal distress, obstructed labour,repture uterus,pph&maternal infection
4.increase maternal anxiety&psychological morbidity.

Incidence:

About 4-14% of pregnancy are post term& this  incidence reduced  significantly when dating of pregnancy is done by first trimester UlS.

Aetiology:

The causes of prolonged pregnancy is unclear& it may represent simple biological variation.
It s more common in:      1.primigravida&nillparous
2. obese one
3. previous history of post term pregnancy lead to increase incidence by 30%
4. A relative adrenocortical insufficiency may contribute to the delay the onset of labour& an increase risk of intrapartum hypoxia or even death.
5.genetic factor: as a woman delivery post term pregnancy in her first pregnancy, had an increase risk of further post term pregnancy.
6. anencephalic baby, placental sulfatase deficiency.

Management:

Induction of labour at 41 weeks is associated with decrease in :

1.PNM&mortality
2. muconium staining
3.small decrease in ClS.

So the management is either:
a. conservative  
b.induction of labour by using PG analogue.

And it done as following:

1.sweepining of the membrane at 40 weeks lead to decrease incidence of post term pregnancy.
2. induction at 41 weeks.
3. if the patient is at 41 weeks or more & refused induction so close fetal surveillance is done by  twice daily NST,maternal cick count,UlS for liquor amount, biophysical profile, Doppler study weekly but there is no clinical evidence to support that fetal monitoring can reduce the Perinatal mortality in post term pregnancy.

Clinical guideline for management of prolonged pregnancy:

after 41 weeks gestation,& if the date is certain, woman should be offered elective delivery.
if the cervix is unfavarouble,cervical ripening should be undertaken.
if expectant management is choosen,assessment of fetal health should be initiated.
from 42 weeks, woman who decline induction of labour,should be offered  increased antenatal monitoring consist of twice weekly CTG,&UlS estimation of AFI.

Related articles:

what is the difference between post maturity syndrome& post term pregnancy.
how would you be sure that the woman is a  case of prolonged  pregnancy.