Medical Biomonitoring of Maternal and Fetal Exposure to Carbon Monoxide and its Modification by Demographic and Obstetric Characteristics

Background: There is a paucity of organized human biomonitoring, including that of carbon monoxide (CO) in the Niger Delta, Nigeria. The study aims to quantify the impact of maternal exposure to CO in the first trimester of pregnancy and its modification by maternal demographic and obstetric factors.

Methodology: It was of cross-sectional design conducted at the Rivers State University Teaching Hospital (RSUTH) in Nigeria. Four hundred and ninety consecutive pregnant women in the first trimester were recruited from the antenatal clinic from January 2021 to January 2022. Demographic, social, and obstetric characteristics were recorded. Maternal exhaled CO concentration (ECOC) and maternal and fetal carboxyhaemoglobin concentrations (MCOHC and FCOHC) were measured with the aid of a smokelyzer. Data were analyzed, using SPSS version 25.0 software. Ethical approval was obtained from the RSUTH Ethics Committee.

Results: The mean values of ECOC, MCOHC, and FCOHC were 3.25±2.51 ppm, 1.15±0.40%, and 0.93±0.72% respectively and the severity (mild, moderate, and severe) of the impact was inversely proportional to the number of women affected. There were statistically significant differences in the mean values of ECOC, MCOHC, and FCOHC in the following maternal characteristics: age, educational levels, BMI, gravidity, and parity. In the case of FCOHC, the measures of the differences were as follows: p:<0.019, <0.020, <0.0001, <0.0001, and <0.038 for age categories, educational levels, BMI, gravidity, and parity respectively. There were statistically significant positive correlations between the BMI and the mean values of ECOC, MCOHC, and FCOHC.

Conclusion: The higher the severity of exposure to CO (mild, moderate, and severe), the lower the number of impacted pregnant women. There were statistically significant differences in the mean values of ECOC, MCOHC, and FCOHC in women of different ages, educational levels, BMI, gravidity, and parity categories.

背景：尼日利亚尼日尔三角洲地区缺乏系统化的人体生物监测工作，其中涵盖一氧化碳（carbon monoxide, CO）相关监测内容。本研究旨在量化妊娠早期母体一氧化碳暴露所产生的影响，并分析母体人口统计学特征与产科因素对该影响的修饰作用。
研究方法：本研究为横断面研究，于尼日利亚河流州大学教学医院（Rivers State University Teaching Hospital, RSUTH）开展。2021年1月至2022年1月期间，研究人员从该院产前门诊连续招募490名妊娠早期孕妇。研究人员记录了受试者的人口统计学、社会学及产科特征信息。借助呼出气一氧化碳分析仪（smokelyzer）测定了母体呼出气一氧化碳浓度（exhaled CO concentration, ECOC）、母体碳氧血红蛋白浓度（maternal carboxyhaemoglobin concentration, MCOHC）以及胎儿碳氧血红蛋白浓度（fetal carboxyhaemoglobin concentration, FCOHC）。采用SPSS 25.0软件对所有数据进行统计分析。本研究已获得RSUTH伦理委员会的伦理审查批准。
研究结果：ECOC、MCOHC及FCOHC的平均值分别为3.25±2.51 ppm、1.15±0.40%与0.93±0.72%；一氧化碳暴露影响的严重程度（轻度、中度、重度）与受影响孕妇人数呈反比关系。不同母体特征分组（年龄、受教育程度、BMI、孕次、产次）的ECOC、MCOHC及FCOHC平均值均存在统计学显著性差异。针对FCOHC而言，各分组差异的P值分别为：年龄分组<0.019、受教育程度分组<0.020、BMI分组<0.0001、孕次分组<0.0001、产次分组<0.038。BMI与ECOC、MCOHC及FCOHC平均值之间均存在统计学显著性正相关。
研究结论：母体一氧化碳暴露的严重程度（轻度、中度、重度）越高，受影响的孕妇人数越少。不同年龄、受教育程度、BMI、孕次及产次分组的孕妇，其ECOC、MCOHC及FCOHC平均值均存在统计学显著性差异。