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 Dr. Lee is the founder and owner of Regrowth LLC, a company based in Los Angeles and dedicated to the treatment of hair loss. He has been developing innovative products and treating hair loss sufferers for the past 16 years. Dr. Lee is the creator of the Xandrox line of hair loss treatments.
Important Note: Due a busy schedule, Dr. Lee cannot answer any new questions at this time; however, he will be providing high quality answers to questions he receives from his own practice exclusively to Morphollica.com regularly
[name not provided]
2004-08-02
Finasteride and birth defects
How real is the threat of a birth defect in a child whose father was taking finasteride at the time of conception?
The package insert for Proscar states under the section on Contraindications:
Because of the ability of Type II 5alpha reductase inhibitors to inhibit the conversion of testosterone to DHT, finasteride may cause abnormalities of the external genitalia of a male fetus of a pregnant woman who receives finasteride.
So, is there a real risk? In theory, yes. For all practical purposes, no.
The specific birth defect that can be caused by the absence or inhibition of the Type II 5-alpha reductase enzyme in the male embryo is hypospadias, a birth defect in which the opening of the urinary tract is on the ventral surface (under side) of the penis rather than at the tip of the penis.
The miniscule amounts of finasteride that could be transferred via the semen during intercourse would never be sufficient to have any effect on the DHT levels of the mother or the fetus at any time during gestation. The average volume of an ejaculate is 5 cc. It would require at least 750 ccs (150 times the average volume) of ejaculate of a man taking finasteride to contain the amount of 5AR inhibition to have any pharmacological effect in the sex partner.
Andersson, S.; Berman, D. M.; Jenkins, E. P.; Russell, D. W.: Deletion of steroid 5-alpha-reductase 2 gene in male pseudohermaphroditism. Nature 354: 159-161, 1991 Greene, S. A.; Symes, E.; Brook, C. G. D.: 5-Alpha-reductase deficiency causing male pseudohermaphroditism. Arch. Dis. Child. 53: 751-753, 1978 Imperato-McGinley, J., Gautier, T.: Inherited 5-alpha-reductase deficiency in man. Trends Genet. 2: 130-133, 1986 Moore, KL and Persaud, TVN: Before We Are Born-Essentials of Embryology and Birth Defects; 6th Edition, Saunders 2003 New England J of Med: 1994, Jan 13; 330 (2) 120-5 Physicians Desk Reference, 58th Edition, 2004, pp. 2172-2178 Thigpen, A. E.; Davis, D. L.; Milatovich, A.; Mendonca, B. B.; Imperato-McGinley, J.; Griffin, J. E.; Francke, U.; Wilson, J. D.; Russell, D. W.: The molecular genetics of steroid 5-alpha-reductase 2 deficiency. J. Clin. Invest. 90: 799-809, 1992 http://encarta.msn.com/encyclopedia_761580700/Human_Sexuality.html#endads
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