Exposure to carbon monoxide during pregnancy can affect both the mother and fetus.
When a fetus is exposed to carbon monoxide:
(1) it takes several hours for fetal levels to reach maternal levels
(2) fetal hemoglobin has a greater affinity to carbon monoxide so blood levels in the fetus tend to be higher
(3) carbon monoxide is cleared more slowly from the fetal circulation
A low-grade exposure to carbon monoxide is unlikely to have an adverse effect on the fetus.
The impact of a severe exposure depends on the gestational age, duration of exposure and management performed. If the mother becomes comatose, then the prognosis for the fetus is poor.
A severe CO exposure can result in:
(1) stillbirth
(2) cerebral palsy
(3) malformations if the exposure is during the first trimester, especially skeletal malformations
Hyperbaric oxygen therapy can be performed during pregnancy and can reduce the severity of fetal injuries. It is important that the hyperoxic period is short.
