Paediatrics: Obstetric problems

2021-03-09 12:00 AM

It is desirable for a paediatrician to attend a birth if there is: · foetal distress (including meconium-stained liquor); · emergency CS;

Obstetric problems

It is desirable for a paediatrician to attend a birth if there is:

  • foetal distress (including meconium-stained liquor);
  • emergency CS;
  • elective CS under general anaesthetic (GA);
  • vaginal breech delivery;
  • rotational forceps;
  • preterm delivery <34wks gestation;
  • severe IUGR;
  • maternal IDDM;
  • serious foetal abnormality; significant iso-immune haemolytic disease.

Small for gestational age

Serial detailed US scans (including Doppler foetal umbilical and cerebral artery blood flow measurement) should be performed to determine:

  • Whether growth reduction is symmetrical or asymmetrical. Symmetrical SGA is usually foetal in origin; asymmetrical suggests placental dysfunction.
  • Foetal growth rate.
  • Foetal health.

 There is ‘rise' risk of foetal hypoxia or death, requiring close antenatal and intrapartum monitoring. Early delivery may be needed. Abnormal Doppler artery measurements (e.g. absent or reversed end-diastolic flow) indicate an especially high foetal risk.

Large for gestational age

A glucose tolerance test should be performed to detect maternal diabetes. Because of ‘rise risk of obstetric complications, a senior obstetrician should supervise the timing and mode of delivery and labour. Specialist input (diabetologist) should also be sought early.

Multiple pregnancies

There is an increased risk of:

  • Perinatal mortality.
  • Preterm delivery.
  • Malformations.
  • Malpresentation.
  • Polyhydramnios.
  • Pregnancy-induced hypertension.
  • APH.
  • Risk increases as the foetus number increases. If 3, selective feticide may be indicated to improve the outcome for survivors.

Oligohydramnios

Liquor volume <500mL. Causes:

  • Placental insufficiency.
  • Preterm prolonged rupture of membranes (PPROM).
  • Foetal urinary tract obstruction or renal disease.

Risks

  • Pulmonary hypoplasia/dry lung syndrome.
  • Contractures/developmental dysplasia of the hip.

Polyhydramnios

Liquor volume >2000mL. Causes:

  • 50% s to foetal disease, e.g. upper GI tract obstruction.
  • 30% idiopathic.
  • 20% of maternal diabetes mellitus.

Risks

  • Preterm labour.
  • Malpresentation.
  • Umbilical cord prolapse.
  • APH.

Amniotic fluid reduction and indomethacin may be beneficial.

Prolonged pregnancy

Longer than 42wks gestation.

  • Significant ‘rise’ perinatal mortality and morbidity (i risk of perinatal hypoxia due to placental insufficiency, obstructed labour due to larger foetus, meconium aspiration, reduced skull moulding).
  • Induction of labour is usually advised after 41wks.

Antepartum haemorrhage

Uterine-placental bleeding after 24wks gestation.

  • Associated with ‘risk perinatal mortality and morbidity; preterm delivery.
  • Major causes are placenta praevia, vasa praevia, placental abruption.
  • Observation or immediate delivery performed depending on severity and gestation.

Umbilical cord prolapse

An obstetric emergency due to a high risk of cord compression and perinatal asphyxia. Requires urgent delivery, usually by CS.

Preterm prelabour rupture of the membranes

  • In 80% preterm labour rapidly follows.
  • In the remaining 20% there is a significant risk of infection and, if PPROM occurs before 20wks, neonatal pulmonary hypoplasia.
  • Treatment: Give mother corticosteroids. Consider antibiotics. Tocolysis is contraindicated.

Preterm labour

Failure to progress

Neonatal and maternal morbidity increase with progressive delay.

  • Caused by: passage obstruction (malpresentation, cephalopelvic disproportion, abnormal pelvic, or cervical anatomy) or uterine dysfunction.
  • Treatment: artificial rupture of membranes (ARM), analgesia, and synthetic oxytocin to hasten delivery. CS may be necessary.

Disturbing/abnormal foetal heart rate patterns

May signify hypoxia. Foetal acidosis results if hypoxia is prolonged or re-peated.

Signs

  • Loss of variability in baseline foetal heart rate (<5beats/min).
  • Late decelerations (in heart rate) (lowest foetal heart rate is > the 30s after peak uterine contraction).
  • Repetitive severe, variable decelerations.
  • Prolonged foetal deceleration (2–9min below the established baseline).
  • Prolonged foetal bradycardia (<100/min).
  • Persistent foetal tachycardia (>170/min).

Tests

  • Foetal blood gas sampling (pH 7.24 = ‘Borderline’ - repeat 30min; 7.2 = ‘Abnormal’—consultant obstetrician and delivery).
  • Postnatal umbilical artery and venous blood gas are used to determine the actual level and nature of acidaemia.

Malpresentation

The most common form is breech (3% at term).

  • Types: extended (hips flexed and knees extended); flexed (hips and knees flexed); footling (feet are presenting part).
  • External cephalic version: may be successful in turning baby between 34and 36wks.
  • Vaginal breech delivery: associated with ‘rise’ perinatal mortality and morbidity; CS is recommended.
  • Other malpresentation is associated with ‘rise' risk of obstructed labour and CS rate (obligatory for brow and transverse presentation).

Shoulder dystocia

Inability to deliver shoulders after the head has been delivered. Cord compression leads to rapid foetal asphyxia.

  • Treatment: urgent delivery—experienced obstetrician, McRobert’smanoeuvre (flexion + abduction maternal hips, thighs on the abdomen), suprapubic pressure, posterior foetal arm extraction, +/– episiotomy
  • Risks: perinatal asphyxia, humeral and clavicle fracture, Erb’s palsy.