Fetal outcome following maternal carbon monoxide poisoning is difficult to predict. Many women have delivered normally after being poisoned, while others have not.
Case selection: pregnant woman exposed to carbon monoxide
The most common adverse outcome is stillbirth.
The trimester of the pregnancy at the time of the exposure needs to be determined.
Carboxyhemoglobin in the fetus
(1) may be very different from that seen in the mother
(2) may not clear from fetal blood as quickly as it clears from the maternal blood once oxygen therapy is started.
The severity of symptoms in the mother seems to be the most important determinant of the outcome.
Testing:
(1) carboxyhemoglobin content of fetal blood
(2) fetal heart monitoring
The investigation should also take into account whether or not:
(1) there was a suicide attempt
(2) there was smoke inhalation from a fire, with the risk of cyanide or other toxic gas
(3) there are any drugs of abuse
Some pregnant woman and neonates have received hyperbaric oxygen, but no controlled studies have been performed.
