PRETERM LABOUR AND PREMATURE

RUPTURE OF MEMBRANES
DR. NABILA
 INTRODUCTION
• Preterm labor is defined as regular
contractions of the uterus resulting in changes
in the cervix that start before 37 weeks of
pregnancy. Changes in the cervix include
effacement (the cervix thins out) and dilation
(the cervix opens so that the fetus can enter
the birth canal).
 EPIDEMIOLOGY
• The incidence of preterm delivery before
37weeks gestation was 11.4% in 2013.
• 40 to 45% are result of spontaneous PTL with
intact membranes.
• 25 to 30% are associated with PPROM.
• 30 to 35% are result of delivery by labor
induction or cesarean delivery for medical
indication such as: preeclampsia with severe
features, placental abruption, or intrauterine
growth restriction.
 RISK FACTORS
• Although many risk factors for PTD have been
identified, up to 50% of PTDS occur in
pregnancies with no known risk factors, and over
half of women with identifiable risk factors will
ultimately deliver at term.
• Many risk scoring systems have been developed
but none have been shown to reduce preterm
birth. Despite this identifying women at risk is
important as treatment options become
available.
 PRIOR PRETERM DELIVERY
• It is single most important identifiable risk factor for
recurrent PTD.
• There is 20% risk for recurrence after a previous
singleton PTD.
• 2.7% risk of PTD after a term delivery.
• 14.7% risk of PTD after a delivery between 32 – 36
weeks.
• 26% risk of PTD after a delivery before 28weeks.
• Multiple prior PTD further increase risk.
• Prior medically indicated PTD also increases risk for a
subsequent medical indicated PTD.
 MULTIPLE GESTATION

• It is the strong predictor for PTD.

• Majority of twin pregnancies deliver at less
than 37weeks because of spontaneous labor
or medical indication of delivery.
• Higher order multiples further increase the
risk.
 CERVICAL SHORTENING
• Cervical shortening in the second trimester is
associated with increased risk for PTD.
• Cervical length should be measured by TVU because
transabdominal u/s may miss cervical length shorter
than 25mm.
• The gestational age at which TVU is most predictive of
PTD is 14- 34 weeks with most TVU cervical length
measurement performed at 18-24 weeks.
• Risk of PTD increased with, the shorter the cervix and
the earlier in gestation the shortening is detected.
• The rate of change in cervical shortening is associated
with increased risk of PTD.
 GENITOURINARY INFECTION
• Genitourinary infection is a risk for PTD.
• BACTERIAL VAGINOSIS increases the risk for
PTD and spontaneous abortion.
• Other infection such as trichomoniasis,
Chlamydia, gonorrhea also increases the risk
for PTD.
• Also pyelonephritis, symptomatic lower UTI,
and asymptomatic bacturia also associated
with increase risk of PTD.
• Mycoplasma species and ureaplasma
urealuticum are most commonly identified
microorganisms in the amniotic cavity of
women with preterm labor.
• These vaginal flora likely ascend from vagina
and have been implicated in chorioamnionitis,
PTL and PPROM.
• Non genitourinary infection such as
pneumonia and peridontal infection has also
been associated with PTD.
• Other maternal characteristics are
• Non hispanic black race
• Interpregnancy interval of less than 6 months
• Maternal nutrition status
• Cervical excision procedure
• Maternal toxin exposure including pollution
and ozone exposure
• Cigarette smoking
 PREVENTION OF PTD
ANTENATAL PROGESTERONE
• The mechanism of progesterone include
reduction of gap junction formation,
oxytocin antagonism,
maintenance of cervical integrity and
anti-inflammatory.
Indication Progestogen Dosing
Prior PTD 17-alpha 250mg IM weekly from 16-
hydroxyprogesteron 36 weeks
caproate
No prior PTD, CL < 20mm Vaginal progesterone gel Daily from diagnosis of
at < 24weeks 90 mg short CL until 36weeks
Vaginal progesterone
capsule 200mg

After 17P is started, it should not be discontinued because that increases

the risk of recurrent PTD.
 CERVICAL CERCLAGE
• Cervical length should be evaluated by TVU every
2 weeks from 16- 23weeks gestation in women
with prior PTD.
• If cervical length < 25mm, cervical cerclage
should be offered.
• Although premature cervical changes might be
result of a structurally weak cervix, paracrine,
endocrine or inflammatory processes.
• Cerclage specifically addresses structural deficits
in the cervix, not necessarily be as effective for
other processes such as infection.
 MANAGEMENT OF INFECTION
• Microbe induced inflammation is associated
with PTL.
• Screening for and treating infection reduces
the risk for PTD and low birth weight
newborns.
• Asymptomatic BV is associated with PTD and
late miscarriages.
• Amsel’s criteria is used for diagnosis of BV.
Diagnosis require three to four findings
Homogenous, white, non inflammatory discharge that smoothly
coats the vaginal walls
Presence of clue cells on microscopic examination
pH of vaginal fluid > 4.5
Fishy odor of vaginal discharge before or after addition of KOH
TREATMENT OF BACTERIAL VAGINOSIS
Clindamycin cream 2% One full applicator (5gm) intravaginally at
bed time for 7 days
Alternate Regimens
Clindamycin 300mg Orally twice daily for 7 days
Clindamycin ovules 100mg Intravaginally once at bedtime for 3 days

SMOKING CESSATION AND OTHER INTERVENTIONS

Women with a previous PTD and who smoked in that
pregnancy had a decrease risk of subsequent PTD if they
had discontinued smoking.
Risk of PTD is not improved with regular nursing contact,
periodontal care, or nutritional supplement.
 ASSESSMENT OF THE SYMPTOMATIC
PATIENT
Are the membranes ruptured? History
Leakage of fluid from cervical os during
sterile speculum examination
Nitrazine reaction of fluid
Ferning of fluid
Placental alpha microglobulin 1 test
Ultrasound for oligohydraminos
Amnioinfusion of indigo carmine(if above
test are non_diagnostic)
Is infection present? Sexually transmitted infection status
Urinary tract infection
Chorioamnioonitis, possibly subclinical
What is the likelihood that the patient will History
deliver prematurely? Fetal fibronectin level(if nothing per
vagina for 24 hrs)
Transvaginal cervical length ultrasound
 MANAGEMENT OF PRE TERM
LABOUR
• After PTL has been diagnosed, several
interventions should be implemented to
improve neonatal outcomes, including
maternal transfer to a facility with a higher
level nursery if indicated, and other
intervention are discussed below.
 ANTENATAL CORTICOSTEROID
TREATMENT
• Treatment with ACS does not increase the risk of
maternal mortality, chorioamnionitis or puerperal
sepsis.
• ACS use is effective with PROM and pregnancy related
hypertension syndrome.
• ACS is recommended between 24-34 weeks gestation
in women who are at risk of PTD within 7 days.
• It is recommended that women less than 333 weeks
gestation who remain at risk of delivery within 7 days,
who received their first ACS dose at least 14days prior,
receive a single repeat course of ACS.
• In general, dexamethasone and betamethasone
show similar results in respiratory distress and
perinatal motality but one meta analysis shows a
decrease in intraventicular hemorrhage and length of
NICU stay with use of dexamethasone compared
with betamethasone.
corticosteroids Dosage

betamethasone Two doses of 12mg IM twice

administered 24 hours apart

dexamethasone Four doses of 6mg given IM every

6 hours
 MAGNESIUM SULFATE FOR
NEUROPROTECTION
• Magnesium sulphate administered
immediately before and at the time of delivery
of a preterm infant decreases the rate of
cerebral palsy.
• Two commonly used regimes are applicable to
women between 24-32 weeks at high risk of
delivery within 24hours
MgSO4 LOADING DOSE MAINTAINANCE DOSE REPEAT TREATMENT

4g over 20 – 30 minutes 1g/hour continued until No immediate repeat dose

birth or for 24 hours

6gm over 20 – 30 minutes 2g/hour continued until If less than 6 hours have
birth or for 12 hours elapsed since cessation,
restart maintainence dose.
If more than 6 hours have
elapsed, rebolus and then
start maintainence dose.
 TOCOLYSIS
• Tocolytic drugs are used for short term
pregnancy prolongation (up to 48 hours), with
the goal of allowing time to administer ACS,
MgSO4 for neuroprotection, antibiotics for
GBS prophylaxis and maternal transfer if
necessary. Pharmaceutical treatment options
are listed in following table.
DRUG DOSAGE COMMENTS CI AND ADVERSE EFFECT
MgSO4 4-6g bolus over Meta analysis failed CI: myasthenia gravis
20 mints then 1- to show Maternal adverse effect:
2g/ improvement in headache, diplopia, muscle
hour(3g/hours outcomes. weakness, pulmonary
maximum) Comparison studies edema, res depression and
show similar arrest at levels>10-12mg/dl.
effectiveness to other Newborn adverse
agents in delaying effects:lethargy, hypotonia,
delivery. res depression
demineralization with
prolonged use.

NIFIDIPINE 30mg oral Nifidipine decreases CI: maternal hypotension

(calcium loading dose the incidence of Maternal adverse effect:
channel then 10-20 mg delivery before 48 flushing, headache, transient
blocker) every 4-6 hours hours. Neonatal hypotension.
mortality not No fetal adverse effect
affected. Dec noted.
RDS,necrotizing
colitis, jaundice.
Terbutaline 0.25mg Betamimetic drugs CI: heart disease, poorly
(betamimet subcutaneously may delay delivery controlled diabetes,
ics) every 20 for 48hours but thyrotoxicosis.
minutes for neonatal outcomes Maternal sdverse effect:
upto 3 doses are variable and cardiac arrythmias, pulmonary
maternal adverse edema, myocardial ischemia,
effects are common. hyperglycemia,
Use FDA warning hyperinsulinemia, altered
against long term thyroid function.
oral use. Fetal adverse effect:
tachycardia, hypocalcemia,
hypoglycemia.

Indometha Loading dose Efficacy of NSAIDS CI: renal and hepatic

cin(NSAIDS) 50mg rectally appears similar to impairement, active peptic
or 50mg- 100 other agents. ulcer disease, oligohydraminos.
mg Maternal adverse effect:
orally.maintaine nausea, heart burn.
nce dose 25- Fetal adverse effectL:
50mg orally constriction of ductus
4hourly for artriosus, not recommended
48hours. after 32 weeks gestation.
 NEONATAL GBS PROPHYLAXIS
• GBS remains the leading cause of mortality due
to infection among neonates, however its
incidence has decreased significantly.
• A vaginal rectal swab for GBS culture should be
obtained if women present with PTL or PPROM.
• Intrapartum antibiotics(penicillin or ampicillin)
should be started and continued until birth or
until it is determined that women is not in true
PTL or a negative GBS culture results become
available.
• If women allergic to penicillin the cefazolin should
be used.
• If women has life threatening penicillin allergy
the clindamycin and vancomycin are used.
• Clindamycin should be used only when GBS
isolate show sensitivity on culture because GBS
isolate shows increasing resistance and
clindamycin has poor penetration into amniotic
fluid.
• Vancomycin should be used in women with
serious penicillin allergies, unknown GBS status
and GBS strain resistant to clindamycin.