Hypoxemia, pregnancy

D. Use in pregnancy. FDA category C (indeterminate). There are no data on teratogenicity. Anaphylactic reaction resulting in shock or hypoxemia in the mother could conceivably adversely affect the fetus. 

PAVMs provide a direct capillary-free communication between the pulmonary and systemic circulations with three main clinical consequences (1) pulmonary arterialbloodpassing through these right-to-left shunts cannot be oxygenated which may lead to hypoxemia, (2) the absence of normal filtering capillary bed allows particulate material (air bubbles or clots) to reach directly the systemic circulation (paradoxical embolism) with potential clinical sequelae in the cerebral circulation (transient ischemic attack, stroke, brain abscess), and (3) these abnormal vessels may rupture into the bronchus (hemoptysis) or the pleural cavity (hemothorax) particularly during pregnancy. 

Several physiological and lifestyle factors increase ascorbic acid hypoxemia. This has been reported for the use of contraceptives, pregnancy (see above), aging, infections, trauma, surgical treatment, and cancer. A clear risk for the development of ascorbic acid deficiency has been found repeatedly in smokers (Moreiras et al., 1994). These findings are based on both a decreased intake of vitamin C rich foods by smokers and the increased metabolism and formation of free radicals resulting in excessive exhaustion of ascorbic acid stores. 

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