Long-term infant outcomes after hyperbaric oxygen treatment for acute carbon monoxide poisoning during pregnancy

Introduction: Carbon monoxide (CO) poisoning in pregnant women is linked to foetal mortality of 36-67%. This study assessed long-term fetal outcomes following hyperbaric oxygen treatment (HBOT) for acute CO poisoning in pregnant women. The effects of clinical severity parameters and pregnancy trimester were also analysed. Methods: A retrospective review of 28 pregnant patients who received HBOT for acute CO poisoning between January 2013-June 2016 was made. Adverse events, birth week, birth weight-height, birth complications, and the age of crawling, walking independently, talking (first words) of their children were recorded. Results: Twenty-eight singleton pregnancies were included. One fetus was dead before HBOT. Three adverse events were reported: abortion, premature birth, and limb malformation. All remaining patients (n = 24) delivered healthy term infants and reported normal neurophysiological development. At final interview the median age of babies was 34 (8-44) months and none had any diagnosed disease. There was no relationship between clinical severity parameters and long-term outcomes. However, the pregnancy trimester at the time of CO poisoning had a significant relationship to birth weight (P = 0.029). Also, the week of pregnancy at the time of the incident correlated with the age of walking independently (P = 0.043, r = 0.436). Conclusions: This is the largest relevant series and longest follow-up to date. Adverse outcomes were likely incidental because the mothers' medical histories revealed alternative aetiologies. There was no definite evidence of fetal morbidity or mortality after HBOT in this study. HBOT may improve long-term fetal outcomes after in-utero CO poisoning without complications.