Meconium passed in labor: how reassuring is clear amniotic fluid?
OBJECTIVE
Clear amniotic fluid is frequently considered a reassuring sign during labor. Our aim was to examine the incidence of meconium that can only have been passed intrapartum and to determine its neonatal associations and whether its absence is a useful sign.


METHODS
This was a prospective cohort study of 8394 "low risk" laboring women at term with clear amniotic fluid at early amniotomy.


RESULTS
Meconium was passed in 5.2% of labors but was not detected until delivery of the fetal head in 51.5% of these. It was associated with moderate-severe acidosis (odds ratio [OR] 4.40; 95% confidence interval [CI] 3.21, 6.03), low Apgar score at 5 minutes (OR 6.49; 95% CI 2.73, 15.44), and neonatal seizures (OR 4.33; 95% CI 3.17, 5.93). However, the sensitivity for these outcomes of the intrapartum passage of meconium and, particularly, its detection before delivery was very poor.


CONCLUSIONS
Although correlated with adverse neonatal outcomes, most affected infants had clear amniotic fluid throughout labor. The presence of clear amniotic fluid is an unreliable sign of fetal well-being.
Greenwood
Catherine
C
The National Maternity Hospital, Dublin, Ireland.
Lalchandani
Savita
S
MacQuillan
Kathryn
K
Sheil
Orla
O
Murphy
John
J
Impey
Lawrence
L
D000328:Adult; D000653:Amniotic Fluid / Q000737:chemistry*; D015331:Cohort Studies; D016001:Confidence Intervals; D036861:Delivery, Obstetric / Q000379:methods*; D005260:Female; D005316:Fetal Distress / Q000175:diagnosis*; D005323:Fetal Monitoring; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D008470:Meconium / Q000378:metabolism*; D008471:Meconium Aspiration Syndrome / Q000175:diagnosis* / Q000453:epidemiology; D016017:Odds Ratio; D011237:Predictive Value of Tests; D011247:Pregnancy; D011256:Pregnancy Outcome; D015995:Prevalence; D011446:Prospective Studies; D012016:Reference Values; D018570:Risk Assessment