Gastrointestinal endoscopy in pregnancy

Table 2 United States food and drug administration categorization of drug safety during pregnancy¹

Category	Risk	Description
A	No risk has been shown in controlled studies	Sufficient, well-controlled studies have not demonstrated a risk to the fetus in any trimester of pregnancy
B	No risk in humans	Sufficient, well-controlled studies have not demonstrated an increased risk of fetal abnormalities despite adverse findings in animals or, in the absence of adequate human studies, animal studies show no fetal risk. The chance of fetal harm is very low but still is a possibility
C	Risk cannot be ruled out	Sufficient, no well-controlled human studies, where animal studies have shown a risk to the fetus. There is a chance of fetal harm if the drug is administered during pregnancy, but the potential benefits should be considered and may outweigh the potential risk
D	Positive evidence of risk	Studies in humans, or investigational or postmarketing data, have demonstrated fetal risk. Nevertheless, potential benefits from the use of the drug may outweigh the potential risk. For example, the drug may be acceptable if needed in a life-threatening situation or for serious disease for which safer drugs cannot be used or are ineffective
X	Contraindicated in pregnancy	Studies in animals or humans (investigational or postmarketing reports) have demonstrated positive evidence of fetal abnormalities or risk that clearly outweighs any possible benefit to the patient

¹Adapted from Food and Drug Administration (1980)[8].