Use of maternal plasma level of zinc-coproporphyrin in the prediction of intrauterine passage of meconium: a pilot study

OBJECTIVE: To evaluate the usefulness of maternal plasma zinc-coproporphyrin (ZCP) level as a marker for intrauterine passage of meconium. METHODS: A pilot study consisting of 10 pregnancies with meconium-stained amniotic fluid and 10 pregnancies with clear amniotic fluid was used. The corresponding plasma and amniotic fluid levels of ZCP were measured using spectrofluorometry. ZCP levels in plasma and amniotic fluid were compared between the two groups and the relation between plasma and amniotic fluid ZCP levels in the clear and meconium-stained groups was assessed using Spearman rank-order correlation. RESULTS: Mean amniotic fluid ZCP was significantly higher in the meconium-stained amniotic fluid as compared to the clear amniotic fluid group. Although mean plasma ZCP levels were higher in the meconium-stained amniotic fluid group, this difference was not statistically significant. There was no significant correlation between plasma ZCP levels and amniotic fluid ZCP, but we could categorize patients according to plasma ZCP levels into four categories with different risks for having meconium-stained amniotic fluid. CONCLUSIONS: Plasma ZCP might be a promising test for prediction of intrauterine passage of meconium in high-risk patients if confirmed by larger studies. The implications of this prediction on management remain unknown.