Premature rupture of membranes (PROM)

Question 1

Define PROM.

Answer 1

Spontanous rupture of membranes in the absence of uterine contractions after 37w

Question 2

What are the risk factors for PROM?

Answer 2

Prior preterm birth

Cigarette smoking

Polyhydramnios

Urinary and sexually transmitted infection

Prior PROM

Low BMI

Question 3

Summarise the epidemiology of PROM.

Answer 3

8% of pregnancies

Question 4

What are signs and symptoms of PROM?

Answer 4

Sudden gush of fluid PV, followed by constant trickle

Question 5

What investigations should be performed for PROM?

Answer 5

General: Assess signs of infection (fever, tachy)

Vaginal: Avoid bimanual if poss!

Speculum: confirm pooling of liquor in vagina

TVUSS: cervical length <15mm?

Foetal Fibronectin (FFN)

Question 6

What is the management for PROM?

Answer 6

Admit for 4 hourly temperature + 24h fetal monitoring.

If clear liquor: expectant Mx for 24h, if >24h –> IOL

If meconium stained/ known GBS: IOL asap +
Abx: benzylpenicillin

Postnatal: Observe neonate for 12h minimum.

Question 7

What are complications associated with PROM? What is the prognosis for PROM?

Answer 7

Increased risk of ascending infection.

60% labour within 24h.

Question 8

Define preterm labour

Answer 8

Regular contractions of the uterus resulting in changes in the cervix that start before 37w of pregnancy.

Question 9

Give 6 major causes of neonatal morbidity arising from preterm birth

Answer 9

Intraventricular hemorrhage grade
Seizures
Hypoxic-ischemic encephalopathy
Necrotizing enterocolitis
Bronchopulmonary dysplasia
Persistent pulmonary HTN

Question 10

Give 3 minor causes of neonatal morbidity arising from preterm birth

Answer 10

Hypotension requiring Tx
Respiratory distress syndrome
Hyperbilirubinemia requiring Tx

Question 11

How is preterm birth classified?

Answer 11

extremely preterm: <28w
very preterm: 28-32w
moderate to late preterm: 32 to <37w

Question 12

Wha† is threatened pre-term labour?

Answer 12

uterine contractions but without cervical dilatation

Question 13

Give 5 risk factors for pre-term labour

Answer 13

Infection
Hx preterm delivery
Multiple pregnancy
Preterm premature rupture of membranes
Problems with the uterus, cervix or placenta

Question 14

What surgery can increase chance of preterm labour?

Answer 14

LLETZ

Question 15

Give 5 maternal risk factors for preterm laobur

Answer 15

HTN / DM
Smoking
IVDU
Underweight/ overweight before pregnancy
Stressful life events

Question 16

Give 2 prophylactic measures to prevent preterm labour

Answer 16

Vaginal progesterone: start between 16-24w + continue to at least 34w

Cervical cerclage between 12-14w

Question 17

In which women are prophylactic measures to prevent preterm labour indicated?

Answer 17

Hx spontaneous preterm birth (up to 34+0w) or mid-trimester loss (from 16+0w onwards)
+
Results from TVUSS between 16+0 and 24+0w that show cervical length of ,<25 mm

Question 18

What are the indications and contraindications for rescue cerclage?

Answer 18

Cervical dilatation in absence of contractions before 23w + unruptured membranes

CI: Bleeding, infection, uterine contractions

Question 19

What investigations are used for preterm labour?

Answer 19

Pelvic exam (speculum, digital examination)

CTG

TVUSS

Lab tests

Question 20

If clinical assessment suggests preterm labour when ,<29+6 w, what action should be taken?

Answer 20

Tx for preterm labour

Question 21

If clinical assessment suggests preterm labour when >,30w what action should be taken?

Answer 21

TVUSS measure cervical length

> 15mm: unlikely in preterm labour

,<15mm: Tx for preterm labour

Question 22

Describe management for preterm labour

Answer 22

Admit to antenatal ward

Maternal corticosteroids to accelerate fetal lung maturation

Tocolytics to delay delivery long enough for steroid administration/ transfer to specialised unit

IV magnesium sulphate for neuroprotection of neonate if birth expected in next 24h

Question 23

What steroids are given in preterm labour?

Answer 23

IM Betametasone in 2 divided doses of 12mg 24h apart

or Dexamethasone in 4 divided doses 6mg every 12h

Question 24

What Tocolytics are used in preterm labour?

Answer 24

1st line: Nifedipine (calcium channel blocker)
2nd line: Atosiban (Oxytocin receptor antagonist)

Question 25

Why must caution be taken when giving magnesium sulphate? What can be done?

Answer 25

Toxicity results in resp depression + arrhythmias Monitor every 4h: obs + deep tendon reflexes Antidote: 10ml 10% calcium gluconate over 10 mins + stop MgSO4

Question 26

If TVUSS is indicated for >,30w pregnancies, but not available what investigation should be performed?

Answer 26

Fetal fibronectin Determines likelihood of birth within 48h

Question 27

What is fetal fibronectin?

Answer 27

Protein produced by fetal cells Found at interface of chorion + decidua "biological glue" binding fetal sac to uterine lining leaks into vagina if pre-term delivery likely

Question 28

How is a fetal fibronectin test taken?

Answer 28

To avoid false +ve: before pelvic exam + TVUSS Speculum + swab

Question 29

4 things that increase risk of false +ve in fetal fibronectin test

Answer 29

ROM Recent SI PV bleeding Recent cervical manipulation

Question 30

Interpret results of fetal fibronectin test

Answer 30

-ve = conc. ,<50 unlikely in preterm labour +ve= con >50 preterm labour likely: steroids + tocolysis

Question 31

What does a negative fetal fibronectin indicate?

Answer 31

Highly unlikely for preterm labour in next 14d

Question 32

Define premature pre labour rupture of membranes

Answer 32

Spontaneous rupture of membranes prior to onset of labour <37w

Question 33

What investigation is used for PPROM?

Answer 33

Speculum If pooling of amniotic fluid- offer care consistent with PPROM If no pooling of amniotic fluid, perform diagnostic testing USS estimation of amniotic fluid vol can give helpful additional info

Question 34

What diagnostic testing is performed if there is no pooling of amniotic fluid in suspected PPROM?

Answer 34

Insulin like growth factor binding protein-1 test or Placental alpha- microglobulin-1 test of vaginal fluid

Question 35

Describe management of PPROM

Answer 35

Admit Prophylactic Abx Intense surveillance for chorioamnioitis or preterm labour Maternal corticosteroids IV Magnesium sulphate if birth expected in 24h DO NOT administer Tocolytics

Question 36

What prophylactic antibiotics are used in PPROM?

Answer 36

Erythromycin PO 250mg QDS for max. 10 days or until in labour (whichever sooner) 2nd line= Penicillin PO

Question 37

Why should tocolytics be avoided in PPROM?

Answer 37

Increased risk of infection

Question 38

If >34w and positive group B strep at any point in current pregnancy, how should a woman with PPROM be managed?

Answer 38

Immediate IOL

Question 39

What can be measured to assess for chorioamniotis in PPROM?

Answer 39

Clinical assessment Maternal CRP + WCC Fetal + Maternal HR