Preterm Delivery

Question 1

DEFINITION AND EPIDEMIOLOGY:

1. Preterm Delivery
2. Preterm Prelabour Rupture of Membranes

Answer 1

1. • Delivery between 24-37w.
     - Delivery risks greater when <34w
     - 5-8% of deliveries
2. Membranes rupture before labour at <37w. Occurs before 1/3 preterm deliveries.

Question 2

COMPLICATIONS(Preterm Delivery):

1. Neonatal:
2. Maternal:

Answer 2

1. • Death(20% of perinatal mortality, up to 85% neonatal death)
     - cerebral palsy(up to 50% of cerebral palsy)
     - chronic lung disease
     - blindness
     - minor disability
     - at 24w, 1/3 handicapped, 1/3 die. risks decrease by 5% at 34w
2. • Severe infection associated.
     - Caesarean section and postnatal endometritis more common.

Question 3

RISK F:

think of uterus as castle and cervix as castle wall holding the defenders in

Answer 3

1. Too many defenders: multiple pregnancy(20% twins, mean time for triplets), polyhydraminos(associated w congenital fetal abnormalities)
2. Defenders jump out as part of fetal survival response: pre-eclampsia, IUGR, infection, placental abruption
3. Poor castle design: uterine abnormalities ie fibroids and congenital abnoralities.
4. Castle wall is weak: Previous cervical surgeries, including multiple dilatations of cervix
5. Enemy knocks down caslte walls: Infections(60%) eg Bacterial vaginosis, Chlamydia, Trichomonas, GBS
6. Enemy gets around walls: UTI, poor dental health
7. Others: Previous history, lower socioeconomic class, extremes of maternal age
8. Medical conditions: thyroid, renal, diabetes
9. Male gender
10. short inter-pregnancy interval
11. High Hb
12. Smoking

Question 4

PREVENTION:

Answer 4

1. Screen high-risk women by measuring cervical length with transvaginal sonography(TVS)
   - normal: 34-40 mm, <15 mm high risk, can consider cervical suture and prophylactic steroids.
2. Cervix: Cerclage. Elective at 12-14w/scan and then suture when significant shortening/rescue suture
3. Progesterone suppository
4. Screen and treat for STI, UTI, bacterial vaginosis. Metronidazole can precipitate preterm birth.
5. Reduction of high order multiples
6. Treating polyhydraminos: amnioreduction/fetal surveillance and NSAIDs
7. Managing medical diseases

Question 5

CLINICAL FEATURES(PRETERM LABOUR):

• regular painful contractions with progressive cervical dilatation.

Answer 5

1. Painful contractions(>50% resolve spontaneously though)
2. Dull, suprapubic ache(painless, cervical dilatation)
3. APH
4. Fluid loss(suggests ruptured membranes)
5. PV exam unless ruptured membranes: effaced/dilating cervix confirms diagnosis

Question 6

INVESTIGATIONS(PRETERM LABOUR):

1. Assess fetal state
2. Assess likelihood of delivery
3. Look for infection

Answer 6

1. CTG and USS
2. Fetal fibronectin if cervix uneffaced(good NPV); TVS of cervical length(>15 mm makes it unlikely). Can also use Bishop’s score to assess although TVS > Bishop’s
   - Fetal fibronectin usually not detectable after 20w.
3. Swabs, maternal CRP, WCC, urine culture

Question 7

MANAGEMENT(PRETERM LABOUR):

• alert paediatricians
  1. Delay delivery and promote maturity
  2. Detection and prevention of infection.
  3. MgSO4
  4. Monitor fetal well-being
  5. Delivery

Answer 7

1. • allows time for transfer to neonatal intensive care facilities
     - steroids btw 24-34w(takes 24h to act). X give in active septicaemia and caution in IDDM
     - tocolysis with nifedipine/atosiban to allow delay. CI: bleeding, infection, significant fetal distress, fetal death. Relative CI: Significant PV bleed, pre-eclampsia, growth restriction
2. • IV Abx and deliver if chorioamnionitis
3. Neuroprotective
4. USS and CTG
5. • Vaginal delivery reduces incidence of respiratory distress syndrome
     - Abx if actual preterm delivery
     - Mobilize paediatric facilities
     - Elective C-section if breech presentation, chorioamnionitis, severe PIH and usual obstetric indications. Forceps and Ventouse for usual indications.
     - X clamp cord until 30s unless neonatal resus needed. No longer than 3 mins

Question 8

COMPLICATIONS(PPROM):

Answer 8

1. Preterm delivery in >50%
2. Chorioamnionitis, funisitis
3. Rarely, cord prolapse
4. Absence of liquor leading to pulmonary hypoplasia and postural deformities.

Question 9

CLINICAL FEATURES(PPROM):

Answer 9

1. Gush of clear fluid
2. Pool of liquid in posterior fornix on speculum
3. Abnormal lie and presentation
   - Digital examination only to exclude cord prolapse in non-cephalic presentation.
4. Chorioamnionitis: Fever, tachycardia, contractions/abdominal pain, uterine tenderness, coloured/offensive liquor

Question 10

INVESTIGATIONS(PPROM):

Answer 10

1. CTG: if persistent fetal tachycardia, likely infection.
2. FBC, CRP, HVS and maybe amniocentesis+culture to look for infections
3. USS: reduced liquor/normal

Question 11

MANAGEMENT(PPROM):

Answer 11

1. Admit and give steroids. IOL once at 36w. Consider delivery at 34w
2. IV Abx if chorioamnionitis suspected and deliver.
3. Erythromycin PO for 10d for prophylaxis/until in established labour. Do not offer co-amoxiclav.