We’ve recently updated our article on hypospadias, a male birth defect in which the opening of the urethra (the tube through which urine passes) is not located at the tip of the penis as it should be. Two of six studies comparing hypospadias cases in boys born to vegetarians versus non-vegetarians have found an increased risk in vegetarians while the other four found no greater risk. The most recent study, which is also one of the largest, found no greater risk for vegetarians.
Our updates include:
- The cause of hypospadias is unknown but it’s believed to be due to a combination of genetic susceptibility and environmental factors including environmental contaminants (1, 2). The different results in studies of vegetarian diets and hypospadias risk could be due to chance or could be due to differences in food choices, supplement use, environmental exposure, or something else.
- The most recent report, from 2012, says that the nationwide rate of hypospadias for the USA is about 64.7 cases per 10,000 male live births or 1 in 155 male live births (3).
- In an earlier article on the Vegan Health website, we reported a 5 times higher risk of having a son with hypospadias for women who ate a vegan diet during pregnancy. But this was for a comparison between vegetarians and non-vegetarians who didn’t use iron supplements. When vegetarians were compared directly to non-vegetarians, the vegetarians had a 3.5 times higher risk (4).
- Parental exposure to pesticides through work or residential lawn care is associated with increased risk of hypospadias in some, but not all studies (1, 5). Dietary exposure to pesticides has been estimated in some studies by examining the use or purchase of organic vegetables. A study from Denmark found no association between use of organic vegetables and fruits and risk of hypospadias (5).
- Taking folic acid supplements in the first trimester reduced the risk of hypospadias in some (6-8) but not all (9-11) studies.
- At least one study has found a link between vitamin B12 deficiency and hypospadias (12). Whether or not a lack of vitamin B12 increases the risk of hypospadias, it plays other important roles so all pregnant women should have a reliable daily source of vitamin B12.
- There’s little evidence for soy, or phytoestrogens from soy, increasing the risk of hypospadias. Two studies reported either no greater risk or a reduced risk when mothers ate soy during pregnancy (13, 14).
In conclusion, there’s reasonable confidence that a vegetarian diet isn’t a significant risk for hypospadias. Making sure pregnant vegans get enough folic acid, vitamin B12, methionine, and choline can help alleviate any potential risks. To learn more, see Hypospadias.
3. Mai CT, Isenburg J, Langlois PH, et al. Population-based birth defects data in the United States, 2008 to 2012: Presentation of state-specific data and descriptive brief on variability of prevalence. Birth Defects Res A Clin Mol Teratol. 2015 Nov;103(11):972-93.
4. North K, Golding J. A maternal vegetarian diet in pregnancy is associated with hypospadias. The ALSPAC Study Team. Avon Longitudinal Study of Pregnancy and Childhood. BJU Int. 2000 Jan;85(1):107-13.
5. Christensen JS, Asklund C, Skakkebæk NE, et al. Association between organic dietary choice during pregnancy and hypospadias in offspring: a study of mothers of 306 boys operated on for hypospadias. J Urol. 2013 Mar;189(3):1077-82.
6. Ormond G, Nieuwenhuijsen MJ, Nelson P, Toledano MB, Iszatt N, Geneletti S, Elliott P. Endocrine disruptors in the workplace, hair spray, folate supplementation, and risk of hypospadias: case-control study. Environ Health Perspect. 2009 Feb;117(2):303-7.
8. Mavrogenis S, Urban R, Czeizel AE, Ács N. Possible preventive effect of high doses of folic acid for isolated hypospadias: a national population-based case-control study. Am J Med Genet A. 2014 Dec;164A(12):3108-14.
11. Carmichael SL, Yang W, Correa A, Olney RS, Shaw GM; National Birth Defects Prevention Study. Hypospadias and intake of nutrients related to one-carbon metabolism. J Urol. 2009 Jan;181(1):315-21; discussion 321.
13. Pierik FH, Burdorf A, Deddens JA, Juttmann RE, Weber RF. Maternal and paternal risk factors for cryptorchidism and hypospadias: a case-control study in newborn boys. Environ Health Perspect. 2004 Nov;112(15):1570-6.