Premature rupture of membranes (term/PROM, preterm/PPROM)

Question 1

What are the three main causes of pre-term delivery?

Answer 1

1. Pre-term labour
2. Preterm premature rupture of membranes
3. Delivery for maternal or fetal indications

Question 2

What is P-PROM?

Answer 2

Preterm (i.e. <37 weeks) premature rupture of membranes in the absence of any uterine activity

Occurs at 24+0 to 36+6 inclusive.

Question 3

What is PROM?

Answer 3

Prelabour (or preterm) rupture of membranes - when membranes rupture but subsequent onset of labour is significantly delayed, after 37 weeks’ gestation

Question 4

How common is PPROM and what % of preterm deliveries result from t?

Answer 4

Occurs in 2% of pregnancies but is associated with around 40% of preterm deliveries

Question 5

What should you look for on speculum examination in PPROM? What other investigation may be useful?

Answer 5

Speculum: Look for pooling of amniotic fluid in the posterior vaginal vault

US: Ultrasound may also be useful to show oligohydramnios.

NB: digital examination should be avoided due to the risk of infection.

Question 6

When should you consider delivery in PPROM?

Answer 6

1. Generally at 34 weeks OR
2. If lung maturity is confirmed OR
3. There is clinical evidence of infection

Question 7

What must not be administered in PPROM?

Answer 7

Tocolytics - they can increase risk of infection in fetus and mother in PPROM

Question 8

What are the benefits of IOL 24hrs after PROM?

Answer 8

Reduced rates of:

• chorioamnionitis
• andometritis
• admission to neonatal unit

Evidence is less clear when PROM occurs preterm i.e. PPROM, and additional indiction is often needed to justify IOL.

Question 9

What investigations should be done to diagnose PPROM/PROM?

Answer 9

Speculum - look for pooling of amniotic fluid

• If observed = (P)PROM
• If not observed –> perform an IGFBP-1 test or PAMG-1 test –> if positive = (P)PROM

NICE: do not use these tests alone to decide what care to offer the woman. But if they are negative then PROM is unlikely and do not offer antibiotics.

• IGFBP-1 = insulin-like growth factor 1
• PAMG-1 = placenal alpha microglobulin-1 (AmniSure test)

Question 10

What is the management of PPROM?

Answer 10

Admit - until 28 weeks if presents earlier

Erythromycin 250mg QDS - prophylactic antibiotics for max 10 days or until established labour (if sooner). 2nd line = oral penicillin

Monitor closely for chorioamnionitis or pre-term labour - x2-3/ week in OPD if they present after 28 weeks, until delivery

IM betamethasone 24 mg 2 doses 12hrs apart - corticosteroids to accelerate fetal lung maturation

IV magnesium sulfate (for neuroprotection of the infant) if birth expected in the next 24 hours.

NB: In general, conservative management is followed in PPROM before 34 weeks’ gestation unless there is evidence of chorioamnionitis and immediate induction of labour is advised in women after 37 weeks’ gestation.

Question 11

What is the management of PROM?

Answer 11

Admit

Speculum - inspect amniotic fluid to see if clear or meconium stained:

• Clear + <24 hrs since PROM - expectant management; 60% go into labour within 24 hours
• Clear + >24 hrs since PROM - offer IOL
• Meconium stained - IOL ASAP

Monitor - 4hr-ly temperature and 24hr fetal monitoring, for signs of chorioamnionitis (rising WCC, CRP etc)

Prophylactic antibiotics

Monitor neonate for 12 hours after delivery - this is when risk of infection is greatest

Question 12

What are the complications of PPROM for the fetus and mother?

Answer 12

fetal:

• prematurity,
• infection,
• pulmonary hypoplasia

maternal: chorioamnionitis

Question 13

At what gestations can steroids be offered in PPROM?

Answer 13

PPROM: 24+0 to 33+6 week

Consider if 34+0 to 35+6 weeks

Question 14

What agents is given in PPROM for neuroprotection of the neonate?

Answer 14

Offer IV magnesium sulphate (for neuroprotection of the neonate) if birth is expected within the next 24 hours.

Question 15

What investigations are used to diagnose infection in a woman with PPROM?

Answer 15

Clinical assessment - FHR

Tests - CRP, WCC

NICE: None of these should be used in isolation to diagnose infection in PPROM.

Question 16

How common is chorioamnionitis? Who is at risk?

Answer 16

5% of all pregnancies

Mother AND fetus both at risk - this is life-threatening

Question 17

What is the cause of chorioamnionitis?

Answer 17

Ascending bacterial infection of the amniotic fluid, membranes or placenta

A major risk factor is PPROM, however, it can still occur when the membranes are still intact which expose the normally sterile environment of the uterus to potential pathogens.

Question 18

What is the general treatment of chorioamnionitis?

Answer 18

Prompt delivery of the foetus (e.g. C-section) and administration of IV antibiotics

Question 19

How soon after PPROM do most patients delivery?

Answer 19

50% within 1 week of PPROM

75% within 2 weeks of PPROM

The earlier in prenancy that PPROM occurs the shorter the interval to delivery

Question 20

What is the prognosis after PPROM?

Answer 20

Postnatal survival is directly related to birthweight and gestational age at delivery,

In pregnancies complicated by PPROM prior to 23 weeks, pulmonary hypoplasia may develop leading to an increased risk of neonatal death, even if delivery occurs at later gestational ages.