Antenatal - Prolonged pregnancy

Question 1

what is prolonged pregnancy?

Answer 1

beyond 40 weeks gestation

Question 2

what is post-term pregnancy and post-dates pregnancy?

Answer 2

• Post-term pregnancy refers to a pregnancy extending past 42 weeks gestation (term refers to the 37-42 week gestation period)
• Post-dates pregnancy refers to a pregnancy extending past the estimated delivery date (EDD), also known as due date at 40 weeks gestation.

Question 3

what are the risk factors for prolonged pregnancy?

Answer 3

• Nulliparity
• Maternal age >40
• Previous prolonged pregnancy
• High body mass index (BMI)
• Family history of prolonged pregnancies

Question 4

what are some clinical features of prolonged pregnancy?

Answer 4

• Some have none at all
• Static growth or potentially macrosomia
• Oligohydramnios
• Reduced fetal movements
• Presence of meconium
  
  • Signs of meconium staining e.g. on nails
• Dry / flaky skin with reduced vernix
  
  • Vernix is a waxy, white substance found coating the skin of newborn babies.

Question 5

what is important to consider in prolonged pregnancies?

Answer 5

inaccurate dating as an alternative “diagnosis” - particularly consider in women who haven’t been compliant with antenatal care

introduction of dating scan between 11+0 and 13+6 has reduced numbers of inaccurately dated pregnancies

Question 6

when is the dating scan recommended and why?

Answer 6

11+0 and 13+6

most reliable as the fetus rarely shows signs of being constitutionally large or small until a later stage of gestation

Question 7

what is checked for on uss in prolonged pregnancy?

Answer 7

check growth, liquor volume and dopplers

Question 8

how is prolonged pregnancy managed?

Answer 8

NICE/RCOG guidelines recommend delivery by 42 weeks gestation to reduce the risk of stillbirth in prolonged pregnancy

• Membrane sweeps – can be offered from 40⁺⁰ weeks in nulliparous and 41⁺⁰ weeks in parous women.
• Induction of labour – usually offered between 41⁺⁰ and 42⁺⁰ weeks gestation.

women who decline induction of labour should be offered twice weekly CTG monitoring and USS with amniotic fluid measurement in an attempt to identify fetal distress. In the event of fetal distress, or other serious complication to mother or child, it may be necessary to conduct an emergency caesarean section.

Question 9

complications

Answer 9

still birth

placental insufficiency higher risk of fetal acidaemia and meconium aspiration in labour