1. Induction of labour and Prolonged pregnancy
Dr. Fayez Jallad

2. Induction of labour Incidence :
Is indicated in about 10 – 20% of pregnancies
Indications :
Is indicated when delivery, due to obsterics or medical reasons , is safer to the mother and/or the fetus than continuation of the pregnancy .
The common indications are :
Postdate
Pre- eclampsia
PROM
Chorioamionitis
IUGR
IUFD
Fetal anomalies
Diabetes millitus
Abruptio placenta
Rh-isoimmunization

3. Contraindication : Placenta praevia
Is contraindicated when the risk of vaginal delivery is unacceptable i.e. when delivery by C/S is safer to the mother and/or fetus than the vaginal delivery.
Absolute :
Placenta praevia
Previous 2C/S, previous one due to recurrent cause, previous classical C/S
Abnormal antenatal CTG
Transverse or oblique lie.
Absolute contracted pelvis.
Active genital herpes infection.
Tumor occupies the pelvis
Cervical carcinoma
Successful pelvic floor repair and successful surgical treatment of stress incontinence.

4. Relative:-
Severe pre-eclampsia
Breech presentation
Multiple pregnancy
Grand multipara
Polyhydramnios.
Presenting part above the pelvic inlet.

5. Complications :
Hyperstimulation → which can lead to fetal distress and uterine rupture.
Failed induction → leading to increase incidence of C/S
Prolonged labour → leading to high incidence of instrumental delivery, C/S and postpartum haemorrhage .
More painful → which require more analgesia
Prematurity
Infection.

6. Bishop Score :
Is used to assess the cervical condition and the station of the head , in order to choose the best method for induction.
It consists of 5 parameters i.e. cervical dilatation , length , consistency and position, and the station of the head , with total score of 13. 3 2 1
≥ 5cm
3-4 cm
1-2 cm
Closed
Cervical dilatation
< 0.5 cm cm
2-1 cm
>2cm
Cervical length
Soft
Medium
Firm
Cervical consistency
Anterior
Central
Posterior
Cervical position
Below ischial spine
-1 – 0 -2 -3
Station of the head

7. Methods of induction : 3 methods : Vaginal prostaglandins AROM
Oxytocin infusion
The selection of the method depends on the Bishop score :
If the Bishop score is < 7 → means unfavorable cervix, to start with PG , followed by AROM ± Oxytocin infusion .
If the Bishop score is ≥ 7 i.e. → means favorable cervix, to start with AROM ± oxytocin infusion .

8. Vaginal prostaglandins :-
Most commonly used is PGE2 (Prostin). Recently PGE1 (Misoprestol- Cytotec) can be used in very small doses.
PGE2 ( Prostin ) is applied in the form of vaginal pessory 3 mg or intracervical gel 0.5mg. PGE1 ( Misoprestol- Cytotec) is applied in the form of vaginal tablet 25µg . The dose of each can be repeated every 4- 6 hours for a maximum of 3 doses in 24 hours .
The main complication of vaginal PG is uterine hyperstimulation which can lead to uterine rupture and fetal distress. Other complications , which are less in vaginal PG compared to systemic PG , are diarrhea and hyperthermia.
If the Bishop score become ≥ 7 , do AROM, and if the effective uterine contractions are not obtained 1- 2 hours from AROM , start oxytocin infusion .
If the cervix remains unfavorable despite the maximum dose of PG ( 3 doses/24hours ), re-evaluate patients and if there is no urgent indication for delivery is present, to repeat the PG next morning .

9. AROM Is indicated if the Bishop score is ≥ 7 .
It induces labour: by increasing the release of PG from the fetal membrane and the decidua, by the mechanical descent of the head , and by increasing the release of oxytocin from posterior pituitary ( Ferguson reflex )
The complications are: cord prolapse, cord compression, placental abruption and infection.

10. Oxytocin :
Is indicated if the effective uterine contractions ( 3 – 4 contractions, each lasting seconds in 10 minutes) are not obtained after 1-2 hours of AROM .
The complications are :
The main complication is uterine hyperstimulation – which can lead to
fetal distress and uterine rupture
Hypotension – if oxytocin given in bolus dose I.V.
Neonatal jaundice – which may occur if the total dose of oxytocin exceeds 20 units .
Water intoxication- which may occur if the total amount of fluids , particularly the electrolyte free fluids , exceeds 1.5 Liters- which may be manifested by confusion , convulsions , coma and even death.

11. How oxytocin to be given in induction of labour
Start by 2mU/min and double the dose every 30 minutes until the effective uterine contractions are obtained , but never to exceed 32 mU/min in mutipara and 64 mU/min in primigravida.
After the effective contractions are established for 30 min , reduce the dose of oxytocin to the minimum required to maintain the effective contractions . The infusion to be maintained after delivery and until the 3rd stage of labour passed safely to prevent the atonic postpartum haemorrhage .

12. How to manage a patient for induction of labour:
Steps which should be taken before start the induction:
Counseling and explanation → why induction is indicated, method of induction to be used and the possible risks to the mother and the fetus.
History → to assess gestational age and to exclude contraindications for induction
Obstetric examination → to assess lie, presentation & engagement
Vaginal examination → to assess Bishop score & pelvic adequacy.
Ultrasound → to assess fetal age, wellbeing and weight, amount of liquor and placental site.
CTG → to assess fetal wellbeing.

13. B- Treatment during the induction :
Good selection of the method of induction → guided by Bishop score.
Proper dose of PG or Oxytocin
Monitoring of labour → Fetal wellbeing, uterine activity, progress of labour and maternal wellbeing.
Adequate pain relief → the best is epidural.
Treatment of uterine hyperstimulation and fetal distress – if any occurs during labour:
Immediately: stop oxytocin infusion, give oxygen by mask, position patient on her side & rapid infusion of cc of normal saline.
If uterine hyperstimulation persisted in spite of the above immediate measures → give Terbutaline 0.25 mg bolus I.V. If hyperstimulation controlled, continue induction & oxytocin infusion can be re-started at low dose. If hyperstimulation persisted, in spite of all above measure, do emergency C/S.
If fetal distress persisted in spite of above immediate measures → do Fetal scalp blood sampling (FSBS) for pH . If the pH is > 7.25, this exclude hypoxia and to continue vaginal delivery. If pH < 7.2, this confirm hypoxia & emergency C/S should be performed. If the pH is between , this is a borderline & to repeat pH after 30 minutes. If pH became > 7.25, continue vaginal delivery. If remains borderline, deliver by C/S.

14. Prolonged pregnancy Definitions:
Post-date pregnancy: means continuation of pregnancy beyond 40 completed weeks.
Post-term pregnancy: means continuation of pregnancy beyond 42 completed weeks.
Incidence:
It occurs in about 5-10 % of pregnancies.
Aetiology:
In the majority of cases there is no underlying cause ie. is a physiological continuation of the pregnancy. Extremely rare it may be due to anencephaly , fetal adrenal hypoplasia or to placental sulphatase enzyme deficiency.

15. Placental insufficiency and hypoxia which leads to:
Risks:
Placental insufficiency and hypoxia which leads to:
Increased perinatal mortality (PNM): the PNM is doubled for each week after 42 weeks.
Meconium aspiration syndrome.
Oligohydramnios and cord compression
B. Increased fetal weight and ossification of skull with decreased moulding, which leads to:
Prolonged labour and failure to progress which leads to ↑ incidence of C/S.
Shoulder dystocia – with its neonatal & maternal risks.
Maternal risks: vaginal & cervical lacerations & rupture uterus.
Neonatal risks:
neonatal asphyxia & death.
cervical cord injury
brachial plexus injury: Erb's palsy (injury to C5&6), Klumpk's palsy (injury to C8&T1) and Phrenic nerve injury (injury to C4)
clavicular & humeral fractures.

16. How to manage patient in Post-date & Post-term pregnancy:
Steps which should be taken before delivery:
Counseling and explanation: explain the risks of post-date and post-term on the fetus.
History → for accurate assessment of gestational age, which should be the first step in patient evaluation, and to exclude contraindications for induction.
Obstetric examination → to assess lie, presentation & engagement.
Vaginal examination → to assess Bishop score & pelvic adequacy.
Ultrasound → at 40, 41, 42 weeks → to assess the amount of liquor, fetal wellbeing & weight.
CTG → every 3 days after 40 weeks →to assess fetal wellbeing.

17. B. Delivery:
In uncomplicated post-date pregnancy, the patient should deliver at 41 weeks days.
The method of delivery is either by induction of labour ( the method of induction depends on Bishop score ) or by C/S if there is contraindication for induction.
If delivery is by induction of labour, a senior obstetrician should attend delivery due to risk of shoulder dystocia, and a peadiatrician should attend delivery due to risk of meconium aspiration.

18. Assessment of gestational age:
Antenatal methods :
First day of LMP → is reliable in 50% of pregnancies.
Ultrasound → the best is Crown-Rump length (CRL) between 7-13 weeks, then Bipariatal Diameter (BPD) & Femur Length (FL) between weeks & then BPD&FL after 26 weeks.
Clinical→ onset of early pregnancy symptoms, early bimanual examination, quickening & serial fundal height.
B. Postnatal methods:
Dubowitz score → which include an assessment of the physical & neurological features of the newborn.
Farr score → which include an assessment of the physical features of the newborn.