NurseSavvy Cheat SheetDisease
Preterm Labor
Pathophysiology & Risk Factors
Preterm labor is regular uterine contractions accompanied by cervical change between 20 0/7 and 36 6/7 weeks of gestation. Contractions on their own are not preterm labor: the cervix has to be dilating or effacing. Because the underlying trigger is often infection, inflammation, or overdistension that cannot be reversed, the goal is rarely to stop labor permanently. It is to hold the pregnancy long enough for antenatal corticosteroids to mature the fetal lungs, and to give magnesium sulfate for fetal neuroprotection when delivery before 32 weeks looks likely.
Signs & Symptoms
EarlyProgresses →
cervical dilation or effacement Hallmark
what separates true preterm labor from contractions aloneregular contractions before 37 weeks Hallmark
low dull backache
constant rather than the sharp pain of a muscular strainrhythmic pelvic pressure
patients describe the baby pushing downmenstrual-like cramping
change in vaginal discharge
newly watery, mucousy, or blood-tingedOther findings
leaking amniotic fluid
membranes have ruptured — report it; preterm rupture is often managed expectantlyDiagnostics & Labs
Diagnostic
sterile speculum and cervical exam Hallmark
confirms dilation, effacement, and ruptured membranesfetal fibronectin swab
a negative result strongly predicts no delivery in the next two weeks; collect before any digital examtransvaginal cervical length
a short cervix raises the risk of preterm birthurinalysis and culture
infection is a common and treatable triggergroup B streptococcus culture
Monitor
continuous fetal heart rate and contraction monitoring
Interventions & Priorities
Suspected preterm labor — first actions
- Confirm cervical changecontractions alone are not preterm labor
- Give corticosteroidsbetamethasone matures the fetal lungs
- Start tocolysisbuys the 48 hours the steroids need
- Magnesium if under 32 weeksfetal neuroprotection
- Alert the neonatal teamprepare for a preterm delivery
Treatments & Medications
betamethasone Hallmark
two intramuscular doses 24 hours apart; matures the fetal lungsmagnesium sulfate Hallmark
slows contractions and protects the fetal brain before 32 weekscalcium gluconate Hallmark
reverses magnesium sulfate toxicitynifedipine
tocolytic; watch for maternal hypotension and flushingindomethacin
tocolytic used before 32 weeks; can close the fetal ductus arteriosusterbutaline
short-term rescue only; causes maternal tachycardiaintravenous penicillin G
group B strep prophylaxis when preterm delivery is expectedPatient Teaching
report more than four to six contractions in an hour> 4-6 per hour
empty the bladder, drink water, then recount
a full bladder and dehydration both provoke contractionsreport any gush or trickle of fluid
report decreased fetal movement
report backache or pelvic pressure that will not ease
return for the second corticosteroid dose
full benefit needs both doses, though some benefit starts within 24 hoursComplications
neonatal respiratory distress syndrome Hallmark
immature lungs lack surfactant — the reason corticosteroids matterintraventricular hemorrhage
necrotizing enterocolitis
neonatal thermoregulation and feeding difficulty
long-term neurodevelopmental impairment
maternal magnesium toxicity
Report Nowescalate immediately
loss of deep tendon reflexes on magnesium Hallmark
the earliest sign of magnesium toxicity — stop the infusion and give calcium gluconaterespiratory rate under 12 on magnesiumRR < 12
urine output under 30 mL per hour on magnesium< 30 mL/hr
magnesium is cleared by the kidneys, so it accumulatesfever with uterine tenderness Hallmark
chorioamnionitis — deliver, do not continue tocolysisfurther cervical change on repeat exam
vaginal bleeding with a rigid uterus
placental abruptionrecurrent late decelerations
Clinical Pearl
Tocolytics do not save the baby — they buy the 48 hours that betamethasone needs to.