Can Carcinoembryonic Antigen Serve as an Indicator for Meconium-Stained Amniotic Fluid?

INTRODUCTION: Meconium-stained amniotic fluid occurs in approximately 12% of all pregnancies. Although most pregnancies with meconium-stained amniotic fluid end with no fetal or neonatal complications, there is still a significant number that result in immediate life-threatening complications to the neonate such as meconium aspiration syndrome. Meconium aspiration syndrome still poses a challenge to clinicians and leads to serious morbidity in affected newborns. To date, meconium-stained amniotic fluid is simply detected by the naked eye of the examining health care provider. There is no objective laboratory test or imaging study for the detection of meconium-stained amniotic fluid. The goal of our study was to determine whether carcinoembryonic antigen (CEA) levels can serve as a reliable marker for the detection of meconium-stained amniotic fluid. METHODS: Carcinoembryonic antigen levels were measured quantitatively in amniotic fluid, urine, and serum samples of pregnant women at term in labor with ruptured membranes. RESULTS: Eighty-one amniotic fluid samples were obtained, 45 clear, eight indeterminate, and 28 with visible meconium stain. Those managing the course of labor were blinded to the result of the assay. Carcinoembryonic antigen levels were significantly higher in meconium-stained amniotic fluid compared with clear amniotic fluid (mean [micrograms/mL] of 2,658 compared with 238, respectively; P<.001). The critical concentration of CEA in meconium-stained amniotic fluid was assessed and a cutoff level was determined. Carcinoembryonic antigen levels in urine and serum samples of women with meconium-stained amniotic fluid remained low and similar to those with meconium-free amniotic fluid. CONCLUSIONS: Carcinoembryonic antigen level in amniotic fluid offers a diagnostic modality independent of the clinician's visual estimate. This may be useful in cases when the presence of meconium is in question.