Some dandruff shampoos should not be used during pregnancy, according to WebMD. Prescription cortisone shampoo would need to be approved by an OB/GYN due to its chemical composition. Prescription antifungal shampoo should not cause problems.
Other factors that could influence a pregnant woman's use of dandruff shampoo include the aroma being too strong, according to WebMD. The site advises expecting mothers to use a scent-free version of the shampoo.
Pregnant women should also avoid chemicals used in dyes, highlights, relaxers and perms, according to WebMD. Although no evidence shows that these products will cause harm, it is wise to avoid them as a precaution.