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 Table of Contents  
Year : 2016  |  Volume : 23  |  Issue : 2  |  Page : 67-70

Penile dimensions of newborns at obio cottage hospital, Port Harcourt, Nigeria

1 Department of Paediatrics and Child Health, Obafemi Awolowo University, Ile-Ife, Osun; Department of Paediatrics, Obio Cottage Hospital, Port Harcourt, Nigeria
2 Department of Paediatrics, Obio Cottage Hospital, Port Harcourt, Nigeria
3 Department of Community Health, Shell Petroleum Development Company, Port Harcourt, Nigeria

Date of Web Publication13-Jul-2016

Correspondence Address:
Jerome Boluwaji Elutayo Elusiyan
Department of Paediatrics and Child Health, Obafemi Awolowo University, Ile-Ife, Osun; Department of Paediatrics, Obio Cottage Hospital, Port Harcourt
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/1117-1936.186296

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Background: Determination of normal reference values for penile dimension may prevent overdiagnosis of micropenis and hence reduce unnecessary investigation and parental anxiety. Only a few data exist on the subject in Nigeria.
Objectives: The study set out to document the stretched penile length (SPL) and penile diameter (PD) of male newborns in Port Harcourt, Nigeria.
Methodology: Four hundred and eleven consecutively delivered male newborns were recruited for this study. SPL and PD were measured using the standard methods with a digital metal caliper. The mean values were determined and compared with other anthropometric parameters.
Results: The mean (standard deviation) SPL from this study was 3.17 ± 0.5 cm and mean PD was 1.07 ± 0.17 cm. There was no significant correlation of the SPL with any of the studied anthropometric parameters, but the PD showed weak positive correlation with estimated gestational age (r = 0.104,P= 0.036), birth weight (r = 0.169,P= 0.001), birth length (r = 0.139,P= 0.006), and head circumference (r = 0.111,P= 0.025). The PD increased significantly across the different weight categories. The third and tenth percentiles for the SPL were 2.3 cm and 2.5 cm.
Conclusion: It is concluded that the mean SPL and PD of newborns in Port Harcourt are 3.17 cm and 1.07 cm, respectively. A PL of <2.3 cm should be taken as representing micropenis.

Keywords: Micropenis, newborn, penile diameter, penile length

How to cite this article:
Elusiyan JB, Ojetayo FG, Fajola AO. Penile dimensions of newborns at obio cottage hospital, Port Harcourt, Nigeria. Niger Postgrad Med J 2016;23:67-70

How to cite this URL:
Elusiyan JB, Ojetayo FG, Fajola AO. Penile dimensions of newborns at obio cottage hospital, Port Harcourt, Nigeria. Niger Postgrad Med J [serial online] 2016 [cited 2020 May 31];23:67-70. Available from: http://www.npmj.org/text.asp?2016/23/2/67/186296

  Introduction Top

Evaluation of the penile dimension is an important component of the newborn examination.[1] The anatomy and size of the penis may be a pointer to serious systemic problem which may have dire medical, social, and psychological consequences on the newborn if undetected.[2],[3] Example is in cases of disorders of sexual differentiation in which there is a disparity between the genetic, gonadal, internal and/or external genital sex.[4] It is well established that normal penile development is dependent on testosterone, its conversion via steroid 5-alpha-reductase to dihydrotestosterone, and a functional androgen receptor.[5],[6]

Penile length (PL) may vary in different populations, with race and ethnicity, and may yield different normal values.[5],[6],[7] Micropenis is defined as a stretched PL (SPL) that is <2.5 standard deviations (SDs) below the mean for age with normal structure and function.[8] It is widely accepted that a PL that is <2.5 cm in a term baby is regarded as micropenis, this, however, may not be universally applicable as studies have shown variation in penile dimensions across many countries.[9],[10],[11] Micropenis is the best-known sign of congenital hypopituitarism and may be seen in several syndromes such as Noonan, Robinow, Klinefelter and Prader–Willi syndromes.[12] Reference values based on local normative data for PL are important to avoid overestimation or underestimation.[12] There have been recent studies from various parts of the world aimed to establish penile norms representing their own populations.[9],[10],[11] Overdiagnosis of micropenis would lead to unnecessary investigations and/or treatment, as well as parental anxiety or stigmatisation.[13] There is, however, a paucity of such data in the African populations. To the best of the authors knowledge, only two recent publications exist in Nigeria, these are from Ibadan, South-West [4] and Enugu, South-East.[14] This study was carried out to establish the normative values of penile dimensions and define micropenis in Port Harcourt, South-South region of Nigeria.

  Methodology Top

The study was carried out at Obio Cottage Hospital (OCH) located at Rumuobiakani, Port Harcourt, Nigeria. The facility operates the private-public partnership and offers comprehensive community health insurance. The scheme was started in 2010 as part of the corporate community social responsibility of the Shell Petroleum Development Company (SPDC). It has 12 medical officers and full compliments of nurses, pharmacist and laboratory scientists. The services are supervised by a consultant paediatrician and obstetric and gynaecologist employed annually by SPDC to serve a year sabbatical. Monthly delivery in OCH averages 300 babies. A convenient sample size of 411 consecutive term male newborns delivered in the facility was recruited between April and August 2015. The newborns were examined in the supine position. The SPL was measured by placing a spatula at the base of the penis while the pubic pad of fat was maximally depressed and the projection of the tip of the glans was marked on the spatula. The distance between the base of the penis and the tip of the glans was measured using a digital calliper. The measurement was taken along the dorsal aspect of the penis. The penile diameter (PD) was measured at the mid-shaft with the digital calliper. All penile measurements were taken within the first 48 h after birth in room temperature by the first author and two trained assistants. Only three babies with hypospadias were excluded from the study. All recruited neonates were uncircumcised.

Gestational age was assessed using the last menstrual period and confirmed by early ultrasound scan done at booking. To benefit from the community health insurance, the women had to book within the first trimester. The anthropometric measurements of the babies were simultaneously taken. Birth weight was obtained by weighing newborns naked on an electronic weighing scale (Seca; Hamburg, Germany) to the nearest 10 g. Recumbent body length was measured with a portable infantometer to the nearest 0.1 cm. The head circumference was determined using a non-elastic measuring tape. Body mass index (BMI) was calculated as weight (kg)/length 2 (m 2). The hospital local Ethics Committee approved the study. Informed consent was obtained from the mothers before the study.

Statistical analyses were performed with SPSS version 20 IBM Corporation, Chicago, IL, USA. Descriptive statistics mean and SD, median and frequency were calculated. The correlations between penile dimensions (PL and PD) and other anthropometric measures (weight, length, head circumference, and BMI of the newborns at birth) were determined by Pearson correlation analysis. Linear regression analyses on the established correlations were conducted. Statistical significance level was established at P<0.05.

  Results Top

Over the 5 months period of 1st April to 30th August 2015 411 consecutively delivered term babies were recruited. The demographic characteristics of the subjects are shown in [Table 1]. All the babies were delivered at term with gestational age ranged from 37 to 42 weeks with a mean (SD) of 39.2 (1.3) weeks. 317 (77.1%) of the babies are either first or second born.
Table 1: Characteristics of the study population (n=411)

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The SPL of the study population ranged from 1.9 to 4.2 cm with a mean and median of 3.17 cm and 3.20 cm, respectively. The PD ranges between 0.6 and 2.2 cm with a mean and median of 1.07 and 1.10 cm, respectively. [Table 1] shows the characteristics of the study population. The percentile ranges of the SPL and PD for the study population are shown in [Table 2]. The third and tenth percentiles for the SPL and PD for the study are 2.3 cm and 2.5 cm and 0.87 cm and 0.90 cm, respectively. The results of the SPL and PD among the categories of birth weight are presented in [Table 3]. There was no significant difference in the SPL across the various weight category, but the PD increased significantly as the birth weight increases (F = 4.655, P = 0.010). The result of the Pearson correlation and regression analysis conducted to show an association between the SPL and PD with the other demographic parameters is shown in [Table 4]. SPL did not show any correlation with any of the parameters, but the PD was weakly correlated with estimated gestational age (r = 0.104, P = 0.036), birth weight (r = 0.169, P = 0.001), birth length (r = 0.139, P = 0.006) and head circumference (r = 0.111, P = 0.025).
Table 2: Percentiles of stretched penile length and penile diameter of the study population

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Table 3: Comparison of penile characteristics across the different weight categories

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Table 4: Relationship between penile dimensions and other demographic characteristics

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  Discussion Top

The mean SPL ± SD of 3.17 ± 0.05 cm obtained from this study is less than that obtained from the two other studies from Nigeria. While Jarret et al. from South-Western Nigeria [4] obtained 3.41 ± 0.47 cm, Chikani et al. from Enugu, South-Eastern Nigeria [14] obtained 3.46 ± 0.14 cm. This study was conducted in Port Harcourt city in the South-South region of the country. A meta-analysis on the raw data from the two earlier studies from Nigeria and present data would have helped to determine if there were real differences in the observed measurements. There have been documented differences in SPL between countries and even within countries. For example, in Turkey a study on 165 newborns reported a mean SPL value of 3.65 ± 0.27 cm,[15] another study on 1217 newborns in another region of Turkey documented mean SPL of 3.16 ± 0.39 cm.[1] While it is possible that the differences are real, differences in methodology may also be contributory. This study used a metal digital calliper to read off the measurement which was not the case with the other two Nigerian studies. Interobserver errors may also have contributed. Differences in measurements as great as 0.5 cm have been reported among different investigators.[12] Other suggested reasons for different penile size measurement across different studies may be environmental, climatic, nutritional, endocrine and genetic.[4]

The PD ± SD of 1.07 ± 0.17 cm obtained from this study is also less than 1.2 ± 0.14 cm obtained by Jarret et al.[4] The Enugu study did not evaluate the PD. Other studies have equally documented different results ranging from 1.1 ± 0.1 cm,[16] 0.82 ± 0.33 cm,[17] and 1.21 ± 0.11 cm.[1] Reasons for these differences may also be as explained for the SPL. However, good enough the SPL is often the only parameter considered when taking decision about micropenis.

This study did not find any correlation between the SPL and other anthropometric measurements. The reported correlation between SPL and these parameters has been variable. While some workers found a positive correlation between SPL and birth weight and length [8],[18] some only found correlation with birth length [1],[14] while others did not find any relationship with any of the parameters like in this study.[4],[7] This observed differences might be because of the differences in the response of the various anthropometric parameter to androgen. The SPL has been shown to depend on the level and action of testosterone, unlike the other parameters. There has been a suggestion that the more the sample size, the more likely a significant correlation may exist.[1] The PD, however, showed a significant positive but weak correlation with estimated gestational age, birth weight, birth length and head circumference this was in agreement with findings of other workers.[1] The SPL also did not show any significant difference across the various weight categories, but the PD increased significantly as the birth weight increases. This may be related to the increased body fat with increasing weight.

The third percentiles for the SPL and PD in the present study were 2.3 cm and 0.87 cm, respectively. Any SPL measurement <2.3 cm would thus be regarded as micropenis for term newborns in our sub-region. This is almost similar to the 2.39 cm from Ibadan and 2.36 cm from Enugu. It may be safe to conclude that any term newborn in Southern Nigeria with SPL <2.3 cm should be evaluated for micropenis irrespective of the culture or region. The cut-off for micropenis for Turkey children [1] is 2.19 cm, 2.5 cm for Malaysian children [6] and 2.13 cm for Saudi Arabian Children.[19] These results support the conclusion of the previous author [1] that a single standard value for a penile dimension cannot be universally applicable for all regions of the world.

It is concluded from this study that the SPL of term newborns in Port Harcourt, South-South Nigeria is 3.17 ± 0.5 cm and the mean PD is 1.07 ± 0.17 cm. The mean SPL from this study is smaller than that of the other two studies from other regions of Nigeria. However, the third centile value of 2.3 cm from our study is similar to that of the other studies. A PL of <2.3 cm should be taken as representing micropenis in this environment.

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Conflicts of Interest

There are no conflicts of interest.

  References Top

Akin Y, Ercan O, Telatar B, Tarhan F. Penile size in term newborn infants. Turk J Pediatr 2011;53:301-7.  Back to cited text no. 1
Perovic SV, Djordjevic ML. Penile lengthening. BJU Int 2000;86:1028-33.  Back to cited text no. 2
Shamloul R. Treatment of men complaining of short penis. Urology 2005;65:1183-5.  Back to cited text no. 3
Jarrett OO, Ayoola OO, Jonsson B, Albertsson-Wikland K, Ritzen EM. Penile size in healthy Nigerian newborns: Country-based reference values and international comparisons. Acta Paediatr 2014;103:442-6.  Back to cited text no. 4
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;307:145-53.  Back to cited text no. 5
Ting TH, Wu LL. Penile length of term newborn infants in multiracial Malaysia. Singapore Med J 2009;50:817-21.  Back to cited text no. 6
Cheng PK, Chanoine JP. Should the definition of micropenis vary according to ethnicity? Horm Res 2001;55:278-81.  Back to cited text no. 7
Tsang S. When size matters: A clinical review of pathological micropenis. J Pediatr Health Care 2010;24:231-40.  Back to cited text no. 8
Kutlu AO. Normative data for penile length in Turkish newborns. J Clin Res Pediatr Endocrinol 2010;2:107-10.  Back to cited text no. 9
Fok TF, Hon KL, So HK, Wong E, Ng PC, Chang A, et al. Normative data of penile length for term Chinese newborns. Biol Neonate 2005;87:242-5.  Back to cited text no. 10
Gabrich PN, Vasconcelos JS, Damião R, Silva EA. Penile anthropometry in Brazilian children and adolescents. J Pediatr (Rio J) 2007;83:441-6.  Back to cited text no. 11
Boas M, Boisen KA, Virtanen HE, Kaleva M, Suomi AM, Schmidt IM, et al. Postnatal penile length and growth rate correlate to serum testosterone levels: A longitudinal study of 1962 normal boys. Eur J Endocrinol 2006;154:125-9.  Back to cited text no. 12
Aaronson IA. Micropenis: Medical and surgical implications. J Urol 1994;152:4-14.  Back to cited text no. 13
Chikani UN, Chinawa JM, Ikefuna AN, Ibekwe MU. Stretched penile length of healthy term neonates: Normative values among Igbo babies in Southeastern Nigeria. J Trop Pediatr 2015;61:69-73.  Back to cited text no. 14
Camurdan AD, Oz MO, Ilhan MN, Camurdan OM, Sahin F, Beyazova U. Current stretched penile length: Cross-sectional study of 1040 healthy Turkish children aged 0 to 5 years. Urology 2007;70:572-5.  Back to cited text no. 15
Flatau E, Josefsberg Z, Reisner SH, Bialik O, Iaron Z. Letter: Penile size in the newborn infant. J Pediatr 1975;87:663-4.  Back to cited text no. 16
Sutan-Assin M, Rukman J, Dahlan A. Penile dimensions of newborn infants. Paediatr Indones 1989;29:146-50.  Back to cited text no. 17
Lian WB, Lee WR, Ho LY. Penile length of newborns in Singapore. J Pediatr Endocrinol Metab 2000;13:55-62.  Back to cited text no. 18
Al-Herbish AS. Standard penile size for normal full term newborns in the Saudi population. Saudi Med J 2002;23:314-6.  Back to cited text no. 19


  [Table 1], [Table 2], [Table 3], [Table 4]

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