Risk Factor: C
Fetal Risk Summary
b-carotene, a natural precursor to vitamin A found in green and yellow vegetables as well as being commercially available, is partially converted in the small intestine to vitamin A (1). Even with therapeutic doses of the drug, serum levels of vitamin A do not rise above normal. Studies in animals have failed to show a teratogenic effect (see also Vitamin A) (2).
A single case describing the therapeutic use of this vitamin in human pregnancy has been located. A 35-year-old woman at 6.5 weeks’ gestation was seen because of her daily intake of 180 mg (300,000 IU) of b-carotene for the past year for the treatment of skin lesions of porphyria (3). She had stopped taking the vitamin at 4.5 weeks’ gestation because of the pregnancy, but her skin still had a yellow-orange tinge. Serum levels of b-carotene and retinol (vitamin A) were determined 2 weeks after her last dose. The b-carotene level was markedly elevated (0.403 mg/dL; normal 0.050.2 mg/dL) whereas the retinol concentration was low normal (0.069 mg/dL; normal 0.050.2 mg/dL) (3). At 18 weeks’ gestation, her b-carotene level had fallen to 0.22 mg/dL. She delivered a healthy, normal-appearing, 3910-g, male infant without skin discoloration at term who was developing normally at 6 weeks of age.
Breast Feeding Summary
No data are available (see Vitamin A).
- American Hospital Formulary Service. Drug Information 1997. Bethesda, MD:American Society of Health-System Pharmacists, 1997:28067.
- Nishimura H, Tanimura T. Clinical Aspects of the Teratogenicity of Drugs. New York, NY:American Elsevier, 1978:252.
- Polifka JE, Dolan CR, Donlan MA, Friedman JM. Clinical teratology counseling and consultation report: high dose b-carotene use during early pregnancy. Teratology 1996;54:1037.