1Department of Obstetrics and Gynecology, University Hospital of Mahajanga, Madagascar
2Department of Obstetrics and Gynecology, University Hospital of Bordeaux, France
3Department of Obstetrics and Gynecology, University Hospital of Fianarantsoa, Madagascar
Submission: July 17, 2018;Published: September 19, 2018
*Corresponding author: Jose Rajaonarison, Department of Obstetrics and Gynecology, University Hospital of Mahajanga, Mahajanga, Madagascar.
How to cite this article: Rajaonarison JJC, Nithart A, Rakotomahenina H, Randaoharison PG, Dallay D,et al. Unintentional Acute Carbon Monoxide
Poisoning During Pregnancy: Five Years of Experience in Bordeaux. Glob J Reprod Med. 2018; 6(1): 555679. DOI: 10.19080/GJORM.2018.06.555679.
Introduction: The objective of the study was to assess cases of maternal and fetal prognosis of carbon monoxide (CO) poisoning during pregnancy at the UHC of Bordeaux.
Materials and method: A retrospective and descriptive study based on observation of cases of carbon monoxide poisoning in pregnant women was conducted at the University Hospital Centre of Bordeaux which review was completed, from 01/01/2011 to 30/06/2016.
Results: The incidence on 24 pregnant women of carbon monoxide poisoning upon the 248 cases reported at the centre was compiled making a rate of 9,67%. Eleven of them were fully monitored. Two patients out of the eleven were tobacco smokers. CO poisoning originated either from: fire (6/11), faulty heating appliances (4/11) or electric short circuit (1/11). Two of the seven patients presenting a COHb level in the blood had an amount of >10%. One patient had suffered with a right bundle block. Eight women out of the eleven were treated with oxygen therapy using face mask on their way to hospital. The centre systematically uses hyperbaric oxygen therapy, which dose and duration vary depending on the case and on the practitioner. Two foetus were affected with in utero growth restriction, and another one with a perinatal asphyxia. Two premature births were admitted to prenatal resuscitation. All along this investigation, no prenatal death were linked to carbon monoxide poisoning.
Conclusion: Complications on the foetus resulting from that hazard are serious and unpredictable. A high rate normobaric oxygen therapy with oro-nasal mask is recommended while awaiting the hyperbaric oxygen which therapy must be systematically administered during pregnancy. Obstetrical management is considered case-by-case.
Abbrevations: CO: Carbon Monoxide; UCAIM: Unit of Coordination and Analysis of Medical information; UHC: University Hospital Centre; ECG: Electrocardiogram; NBO: Normobaric Oxygen; HBO: Hyperbaric Oxygen
Carbon monoxide (CO) poisoning is a common intoxication found in France. It causes serious outcomes on population with a mortality rate of 0,31/100000 in some areas of France , a sudden lethality for 1,26% , and neurological sequelae that might be severe. In France, 5,4% of victims are pregnant women . The rate of fetal mortality due to CO poisoning during a pregnancy can reach 19 to 24% . The physiopathological suggestions had proved that a foetus is more susceptible regarding of intensity and duration of exposure than a mother. Although various studies had brought light on how to understand physiopathologies, diagnosis, therapy principle; the frequency of neurological sequelae, pronostic factors, the fetal prognosis of a CO exposure during pregnancy and the monitoring system of
victims remain in shade. Practices diverge on how to prescribe an hyperbaric oxygen therapy.
The following study aims to describe maternal and fetal complications of CO poisoning during pregnancy. From the obtained results, the prescription of an HBO therapy, maternal sequelae and fetal prognosis will be discussed.
A retrospective and descriptive study based on observation of patients was conducted. Women poisoned with carbon monoxide and admitted to hospital were included in the study. A list of patients was retrieved from the UCAIM (Unit of Coordination and Analysis of Medical information) data at the UHC (University Hospital Centre) of Bordeaux over 5 years and 6 months (from
01/01/2011 to 30/06/2016). Patients who did not deliver in
Bordeaux or not having a filed telephone number were excluded
from the investigation. Other patients who had delivered in other
centres were contacted by phone calls to get informed on the
evolution of the pregnancy and its outcomes. For each patient, the
background of the poisoning was investigated (cause, duration
of exposure, ambient concentration of CO), together with clinical
and paraclinical manifestations, management (normobaric and
hyperbaric oxygen therapies), the evolution of the pregnancy and
all possible sequelae (Table 1-2).
Data from the twenty four pregnant women were collected
upon 248 cases of CO poisoning treated at the centre giving a rate of
9,67%. Eleven of them were completely monitored, the remaining
(13cases) were not included in the study. The epidemiologies and
features of the poisoning were respectively shown in table I and
II. Eight women were asymptomatic and four others presented
neurological symptoms as (headaches, dizziness, malaise, mild
loss of consciousness, asthenia). Two of them have shown one
with digestive signs (nausea, vomiting) and the other with
asthenia. Obstetrical manifestations were illustrate on table III. An
Electrocardiogram (ECG) performed on ten patients revealed that
one of them had presented a right bundle block. Eight patients out
of the eleven were treated with face fitted masked normobaric
oxygen (NBO) at a flow rate of 15L/min before admission to
hospital. The average time elapsed between the intoxication and
the onset of an hyperbaric oxygen (HBO) treatment is of 11,75h
with margins of 4 to 48h. The pressure used was of 1,5ATA
(Atmosphere absolute) (9/11) and 2,5ATA (2/11). The duration
of the HBO treatment depends on medical practitioners and
according to the seriousness of cases; ranging from 115 min for
8 patients, 150min for two others and 190min for the last one.
Perinatal complications were given on table IV. Within a period of
1 to 5 years one child out of 11 had two conditions of bronchiolitis
before the age of two years (Table 3&4).
Carbon monoxide poisoning is the most familiar intoxication in
France. The InVs (Institute of Health Surveillance) records 4000
cases per year but its incidence is underestimated for several
reasons: reporting is not obligatory, intoxications from smokes
are excluded from the declared case, and finally, since that gas
is odourless and colorless and symptoms do not always appear,
some cases of CO poisoning are often misdiagnosed . In 2012,
that condition was a very common hazard during pregnancy with
a rate of 9,67% in Bordeaux , 8,5% , in United States and
less frequent in northern France (5,4%) . Among the reported
causes were: fire, and faulty heating appliances which promote the
spate of occurence during wintry season . Practically, managing
CO poisoning encounters issue in diagnosis. Its definition varies
from one centre to another, ambient concentration is changing,
and the duration of exposure is often unknown [6,9]. Clinical signs
depend on the atmospheric concentration at the intoxication. In
a range of 100-200ppm, headaches, nausea/vomitings, dizziness,
asthenia and malaise appear. Within 300-500ppm, the patient
may present polypnea, dyspnea, tachycardia, chest pains, and
slight loss of consciousness. At 1000ppm, a convulsion, or a coma
may take place. Between 2000-5000ppm death occurs in few
Minor disorders are noticed within 30 to 40% of cases ,
and more serious neurological manifestations occur in 1 to 4%
. During pregnancy, the most common signs are the reduction
of the active fetal movement (3cases in this series), threat of
a premature delivery (1case) but the poisoning may also be
without symptoms. On a paraclinical basis, an Electrocardiogram
displayed a common epicardial or endocardial ischemia . In this series one case of bundle block was recorded. The plasmatic level
of COHb correlates with the time elapsed after the hazard. Four
patients were reported without that level. It was also the case of
another study conducted at the same region in 2012, by Bernadet
P and al.  all 76/252 cases were reported without the dosage.
For a therapy management, a systematic treatment using NBO
must be performed.
It was one of the basic therapy that is achieved at high flow rate
(12-15L/min) using a face mask, and which should immediately be
started at the premices of the accident. A regular check of the fetal
heart beat is practiced for 1h , and the oxygen therapy must be
continued for 16h or more if no improvement is observed or the
hyperbaric oxygen is not available . Eight patients out of the
eleven had followed this treatment. Applying hyperbaric oxygen
therapy (HBO) fastens the dissociation of COHb molecules, reduces
its elimination half-life, rise the plasmatic concentration of oxygen
and prevent formation of free radicals [15,16]. Its prescription
during pregnancy is beneficial since it contributes to reduce the
severity of the fetal injuries, the occurence of malformations and
it was proved to be safe [17,18]. According to some authors, no
significant difference of effectiveness is noticed when compared
with a NBO therapy . In literature the pressure used is usually
of 2ATA for 120 min or 2,5 ATA for 90min .
Silverman RK, et al.  recommended another administration
when maternal or fetal symptoms remain 12h after the first
application. In Bordeaux, such session is systematically performed
during pregnancy not regarding the severity of the intoxication.
Oxygen pressure of 1,5ATA (9/11) for 115min is commonly used
(8/11). A long record of the fetal heart beat is obligatory with a
management of possible risk of premature delivery. One case
was handled all along this study. A fetal hypoxia requiring an
emergency caesarian section in one of the pregnant patient was
the most frequent complication of this condition. It came out of
a maternal hypoxia thanks to a high affinity of CO with the fetal
haemoglobin, the delay of its elimination, and the misuse of oxygen
by cells [3,4]. At a beginning of a pregnancy, malformations like
microcephaly, dysgenesis of the telencephalon may occur within
a second quaterly of brain injuries at the basal ganglia, brainstem,
cerebellum and the spinal cord [15,21,22]. It resulted in hypotonia
or even a cerebral palsy after delivery [23,24].
The absence of other causes of IUGR which involved two cases
of this series allow us to realize that such growth restriction
would come from the poisoning. Such complication had not yet
been reported in literature. Moreover, the occurrence on one of
the patient of a subchorionic hematoma could not be otherwise
explained. Perinatal mortality associated to this intoxication can
reach up to 36-67%. On the long run, no infant pathology was
linked to a CO poisoning. The cases of broncholitis found on a
child were not necessarily related to in utero CO exposure. As for
maternal death, figure could attain 1,26% of the intoxicated. The
prognosis is not different from that of non-pregnant women. No
maternal death related to the poisoning was recorded during the
study, however literature reported cases of adult losses during
pregnancy . Severe manifestations occurred in 1 to 4% of cases
[12,25,26], leaving survivors with sequelae mainly depression,
anxiety, or impaired cognitive ability resulting in disturbances at
The presence of a cardiac comorbidity (one woman has a VSD
in this series), an abnormality of the Electrocardiogram (one case
of right bundle block found on one patient) and various forms
of poisoning (smokes from fire on 6 of the pregnant women)
are part of the pronostic factors of the maternal mortality .
Neurological sequelae are feared when a loss of consciousness
or an initial cerebellar syndrom [18,29], headaches, fainting or
dizziness occurred, or failing a HBO therapy particularly when the
blood level of COHb is >25% [15,30].
CO poisoning is not an exceptional condition at the centre of
the study. A better management is obtained through a systematic
oxygen therapy during pregnancy and it can improve the figure
of prognosis. The French population still need to be informed
of the risk of contracting home CO poisoning, its outcomes and