Obstetrics Simplified - Diaa M. EI-Mowafi
Premature Rupture of Membranes (PROM)
Definition
It is rupture of membranes before onset of labour so it is more accurate to call it "prelabour rupture of membranes".
Incidence
10% of term pregnancies and more in preterm labour.
Aetiology
The following factors are incriminated:
- Cervical incompetence.
- Polyhydramnios.
- Multiple pregnancy.
- Malpresentations as the presenting part is not fitting against the lower uterine segment.
- Chorioamnionitis.
- Low tensile strength of the membranes.
Diagnosis
- History: of gush of fluid per vagina that moists vulval pads.
- Drawback: Vulval pads can be moisted with urine or vaginal discharge which can be mistaken with the amniotic fluid.
- Nitrazine paper test:
- The colour turns from yellow to deep blue due to alkalinity of the amniotic fluid.
- Laboratory analysis: for creatinine, urea and uric acid in the fluid
sample.
- Drawback: these components are present in the urine.
- Fern test:
- Visualization of fern-like pattern of dried amniotic fluid on a glass slide under microscopy due to presence of protein.
- Drawback: protein may be present in urine.
- Sterile speculum examination:
- to observe the escape of amniotic fluid from the external os.
- Dye injection:
- Through abdominal needle under ultrasonic guide into the amniotic sac and observation of its passage through the external os or even in the vulval pad.
- Drawback: It carries risk of foetal trauma particularly if a large amount of the amniotic fluid was drained.
- Vernix, meconium or alpha-fetoprotein detection:
- In the fluid sample is diagnostic.
- Ultrasound:
- is an ideal non-invasive technique for the detection of the residual amount of amniotic fluid.
Complications
- Preterm labour: with the risk of prematurity.
- Infection: chorio-amnionitis, septicaemia and foetal pneumonia.
- Foetal deformities and distress: due to oligohydramnios.
Management
Gestational age over 36 weeks
- In absence of infection, foetal distress and abnormal lie, wait for 24 hours as about 90% of patients with PROM will pass into spontaneous labour. Prophylactic antibiotic can be given during this period.
- PGE2 and / or oxytocin is used for induction of labour in patients did not pass into labour after 24 hours.
Gestational age between 34-36 weeks
- In absence of infection and foetal distress, wait for 48 hours as rupture of membrane itself will accelerates lung surfactant production and hence lung maturity.
- Induce labour after 48 hours with PGE2 and /or oxytocins.
- Prophylactic antibiotics are given during this period.
- Caesarean section is indicated in breech presentation < 36 weeks’ gestation.
Gestational age between 28-34 weeks
In absence of infection, the main aim is to manage the case conservatively till the 35th week when lung maturity mostly occurs and the baby can survive.
Conservative management as follow:
- Rest in bed as long as there is escape of liquor with restriction of efforts later on particularly those that increase intra-abdominal pressure.
- Temperature is recorded every 4 hours.
- Observation for malaise, abdominal pain, uterine tenderness and amount of escaped liquor on sterile vulval pads.
- Leucocytic count and C-reactive protein may be done every other day.
- Prophylactic antibiotics may be given although this is not advised by some authors as it may lead to colonisation of resistant strains of organisms in the genital tract.
- Tocolytic drugs: are given if uterine activity starts.
- Corticosteroid therapy: is given for 48 hours if labour was imminent or will be induced before 35 weeks.
Gestational age less than 28 weeks
There is little chance of foetal survival and the condition is usually considered as inevitable abortion.
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Edited by Aldo Campana,