Association between exposure to air pollution during pregnancy and false positives in fetal heart rate monitoring

Seiichi Morokuma,Shin Yamazaki,Hiroshi Nitta,Takehiro Michikawa,Kiyoko Kato

doi:10.1038/s41598-017-12663-2

Seiichi Morokuma, Shin Yamazaki + Show 3 more

Open Access

https://doi.org/10.1038/s41598-017-12663-2

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Abstract

Fetal heart rate (FHR) monitoring is essential for fetal management during pregnancy and delivery but results in many false-positive diagnoses. Air pollution affects the uterine environment; thus, air pollution may change FHR reactivity. This study assessed the association between exposure to air pollution during pregnancy and FHR monitoring abnormalities using 2005–2010 data from the Japan Perinatal Registry Network database. Participants were 23,782 singleton pregnant women with FHR monitoring, without acidemia or fetal asphyxia. We assessed exposure to air pollutants, including particulate matter (PM), ozone, nitrogen dioxide (NO2), and sulfur dioxide (SO2). In a multi-trimester model, first-trimester PM exposure was associated with false positives in FHR monitoring (odds ratio [OR] per interquartile range (10.7 μg/m3) increase = 1.20; 95% CI: 1.05–1.37), but not second-trimester exposure (OR = 1.05; 95% CI: 0.91–1.21) and third-trimester exposure (OR = 1.06; 95% CI: 0.96-1.17). The association with first-trimester PM exposure persisted after adjustment for exposure to ozone, NO2, and SO2; however, ozone, NO2, and SO2 exposure was not associated with false positives in FHR monitoring. First-trimester PM exposure may alter fetal cardiac response and lead to false positives in FHR monitoring.

Highlights

Research on fetal heart rate (FHR) monitoring has been conducted to determine the clinical significance of different morphological categories of Fetal heart rate (FHR) tracing
We considered cases that presented with FHR monitoring abnormalities, without acidemia or fetal asphyxia, with umbilical arterial blood pH ≥ 7.2, and Apgar score ≥7, as false positives[20,21], and examined the association with exposure to air pollution during pregnancy
In a multi-trimester model, first-trimester particulate matter (PM) exposure was positively associated with false positives in FHR monitoring (OR per interquartile range (10.7 μg/m3) increase in PM concentrations = 1.20; 95% confidence intervals (CIs): 1.05–1.37)

Summary

Introduction

Research on fetal heart rate (FHR) monitoring has been conducted to determine the clinical significance of different morphological categories of FHR tracing. Abnormalities in FHR monitoring can appear as late deceleration (LD), severe variable deceleration (SVD), loss of variability (LV), or bradycardia When these occur alone or in combination, non-reassuring fetal status is diagnosed, and immediate delivery of the fetus is recommended[3]. Since FHR monitoring is an essential component of fetal management, pursuing the causes of false positives in FHR monitoring is extremely important. We hypothesized that exposure to inflammation caused by air pollution changes the fetal heart rate responses and causes false positives in FHR monitoring. We considered cases that presented with FHR monitoring abnormalities, without acidemia or fetal asphyxia, with umbilical arterial blood pH ≥ 7.2, and Apgar score ≥7, as false positives[20,21], and examined the association with exposure to air pollution during pregnancy

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