Korean J Urol.  2015 Mar;56(3):248-253. 10.4111/kju.2015.56.3.248.

Penile length, digit length, and anogenital distance according to birth weight in newborn male infants

• Park JY
• Lim G
• Oh KW
• Ryu DS
• Park S
• Jeon JC
• Cheon SH
• Moon KH
• Park S
• Park S

• KMID: 2133294
• DOI: http://doi.org/10.4111/kju.2015.56.3.248

Abstract

PURPOSE
Anogential distance (AGD) and the 2:4 digit length ratio appear to provide a reliable guide to fetal androgen exposure. We intended to investigate the current status of penile size and the relationship between penile length and AGD or digit length according to birth weight in Korean newborn infants.
MATERIALS AND METHODS
Between May 2013 and February 2014, among a total of 78 newborn male infants, 55 infants were prospectively included in this study. Newborn male infants with a gestational age of 38 to 42 weeks and birth weight>2.5 kg were assigned to the NW group (n=24) and those with a gestational age<38 weeks and birth weight<2.5 kg were assigned to the LW group (n=31). Penile size and other variables were compared between the two groups.
RESULTS
Stretched penile length of the NW group was 3.3+/-0.2 cm, which did not differ significantly from that reported in 1987. All parameters including height, weight, penile length, testicular size, AGD, and digit length were significantly lower in the LW group than in the NW group. However, there were no significant differences in AGD ratio or 2:4 digit length ratio between the two groups.
CONCLUSIONS
The penile length of newborn infants has not changed over the last quarter century in Korea. With normal penile appearance, the AGD ratio and 2:4 digit length ratio are consistent irrespective of birth weight, whereas AGD, digit length, and penile length are significantly smaller in newborns with low birth weight.

Keyword

Anthropometry; Newborn infants; Penis

MeSH Terms

Anthropometry
*Birth Weight
*Body Weights and Measures
Cross-Sectional Studies
Fingers/*anatomy & histology
Gestational Age
Humans
Infant, Low Birth Weight
Infant, Newborn
Male
Organ Size
Penis/*anatomy & histology
Republic of Korea

Figure

• 

  Fig. 1 Measurement of anogenital distance (AGD) and 2:4 digit lengths. (A) AGD has been measured in three ways (AGD1, AGD2, AGD3), AGD3 appears to be the most reliable and repeatable measurement. (B) Digit lengths is measured form the basal crease to the tip on the ventral surface of the hand at the point midway across a line perpendicular to the base using rulers.

Reference

1. Welsh M, Saunders PT, Fisken M, Scott HM, Hutchison GR, Smith LB, et al. Identification in rats of a programming window for reproductive tract masculinization, disruption of which leads to hypospadias and cryptorchidism. J Clin Invest. 2008; 118:1479–1490.

2. Macleod DJ, Sharpe RM, Welsh M, Fisken M, Scott HM, Hutchison GR, et al. Androgen action in the masculinization programming window and development of male reproductive organs. Int J Androl. 2010; 33:279–287.

3. van den Driesche S, Scott HM, MacLeod DJ, Fisken M, Walker M, Sharpe RM. Relative importance of prenatal and postnatal androgen action in determining growth of the penis and anogenital distance in the rat before, during and after puberty. Int J Androl. 2011; 34(6 Pt 2):e578–e586.

4. Drake AJ, van den Driesche S, Scott HM, Hutchison GR, Seckl JR, Sharpe RM. Glucocorticoids amplify dibutyl phthalate-induced disruption of testosterone production and male reproductive development. Endocrinology. 2009; 150:5055–5064.

5. Kim KS, Liu W, Cunha GR, Russell DW, Huang H, Shapiro E, et al. Expression of the androgen receptor and 5 alpha-reductase type 2 in the developing human fetal penis and urethra. Cell Tissue Res. 2002; 307:145–153.

6. Eisenberg ML, Jensen TK, Walters RC, Skakkebaek NE, Lipshultz LI. The relationship between anogenital distance and reproductive hormone levels in adult men. J Urol. 2012; 187:594–598.

7. Buck JJ, Williams RM, Hughes IA, Acerini CL. In-utero androgen exposure and 2nd to 4th digit length ratio-comparisons between healthy controls and females with classical congenital adrenal hyperplasia. Hum Reprod. 2003; 18:976–979.

8. Chung KH, Choi H, Kim SW. Penile and testicular sizes of Korean children. Korean J Urol. 1987; 28:255–258.

9. Wiygul J, Palmer LS. Micropenis. ScientificWorldJournal. 2011; 11:1462–1469.

10. Tsang S. When size matters: a clinical review of pathological micropenis. J Pediatr Health Care. 2010; 24:231–240.

11. Lee JH, Ji YH, Lee SK, Hwang HH, Ryu DS, Kim KS, et al. Change in penile length in children: preliminary study. Korean J Urol. 2012; 53:870–874.

12. Kim TH, Lee HH. Anogenital distance in newborns. Reprod Biomed Online. 2014; 29:771.

13. Dean A, Sharpe RM. Clinical review: anogenital distance or digit length ratio as measures of fetal androgen exposure: relationship to male reproductive development and its disorders. J Clin Endocrinol Metab. 2013; 98:2230–2238.

14. Matsuo N, Ishii T, Takayama JI, Miwa M, Hasegawa T. Reference standard of penile size and prevalence of buried penis in Japanese newborn male infants. Endocr J. 2014; 61:849–853.

15. Thankamony A, Ong KK, Dunger DB, Acerini CL, Hughes IA. Anogenital distance from birth to 2 years: a population study. Environ Health Perspect. 2009; 117:1786–1790.

16. Manning JT. Digit ratio (2D:4D), sex differences, allometry, and finger length of 12-30-year olds: evidence from the British Broadcasting Corporation (BBC) Internet study. Am J Hum Biol. 2010; 22:604–608.

17. Salazar-Martinez E, Romano-Riquer P, Yanez-Marquez E, Longnecker MP, Hernandez-Avila M. Anogenital distance in human male and female newborns: a descriptive, cross-sectional study. Environ Health. 2004; 3:8.

18. Swan SH, Main KM, Liu F, Stewart SL, Kruse RL, Calafat AM, et al. Decrease in anogenital distance among male infants with prenatal phthalate exposure. Environ Health Perspect. 2005; 113:1056–1061.

19. Ventura T, Gomes MC, Pita A, Neto MT, Taylor A. Digit ratio (2D:4D) in newborns: influences of prenatal testosterone and maternal environment. Early Hum Dev. 2013; 89:107–112.

20. Lu H, Huo ZH, Liu YJ, Shi ZY, Zhao JL. Correlations between digit ratio and infertility in Chinese men. Early Hum Dev. 2012; 88:865–869.

21. Manning JT, Barley L, Walton J, Lewis-Jones DI, Trivers RL, Singh D, et al. The 2nd:4th digit ratio, sexual dimorphism, population differences, and reproductive success. evidence for sexually antagonistic genes. Evol Hum Behav. 2000; 21:163–183.

22. Auger J, Eustache F. Second to fourth digit ratios, male genital development and reproductive health: a clinical study among fertile men and testis cancer patients. Int J Androl. 2011; 34(4 Pt 2):e49–e58.