Neonatal stretched penile length: relationship with gestational maturity and anthropometric parameters at birth

Advancing Precision in Penile Length Measurement: Evidence-based Synthesis of Stretched Penile Length INdicator Technique (SPLINT)

Purpose

The purpose of this study was to synthesize evidence and propose a technique for estimation of stretched penile length (SPL) applicable to children.

Materials and Methods

This review has been conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. PubMed, Embase, and Scopus databases were queried on penile length (PL) measurement techniques in humans published from 1990 onward. The devices and the techniques used for PL measurement, state of the penis, the habitus of the participants, proximal and distal landmarks for measurement, handling the foreskin and pubic pad of fat, optimal stretching of the penis, and other factors (including the environment) which should be accounted for in the technique were identified from the study cohort (90895 participants across 145 included studies).

Results

PL has been represented through flaccid (33.79%), stretched (81.3%), and erect (12.41%) PLs as well as the greatest corporeal length (1.4%). Following devices have been used to measure the PL in the study cohort: rulers [54.68%], calipers [9.7%], measuring tapes [14.5%], coloured measuring strips [2.06%], spatulas/tongue depressors [11.03%], FitKit, syringe [1.4%], cotton swab (and ruler), titan cylinders, slide gauge and ultrasonography [1.37%]. The factors relevant to SPL measurement have been incorporated into the proposed SPL INdicator Technique (SPLINT) which is essentially a holistic extension of the "Conventional PL Measurement" technique.

Conclusions

There is a wide range of heterogeneity in the technique for estimation of PL across the study cohort; the underlying factors have been identified along with the respective variables, and the SPLINT for SPL has been described.

Estimation of Reference Values for External Genitalia Parameters in North Indian Preterm and Term Male Newborns

OBJECTIVES

To generate gestation-wise normative data of external genitalia measurements in North Indian term and preterm male newborns.

METHODS

This was a hospital-based cross-sectional observational study. Male neonates born between 28-42 wk of gestation (at 24-72 h of life) were consecutively recruited in the study. Newborns with major congenital malformations, chromosomal anomalies, multifetal gestation and birth injuries were excluded. Data on various genital measurements were collected [Stretched penile length (SPL), penile width (PW), upper anogenital distance (AGDu), lower anogenital distance (AGDl) and anogenital ratio (AGR)].

RESULTS

Out of 532 newborns, 208 (39.1%) were preterm. Mean (± SD) SPL and PW were 27.9 ± 3.6 mm and 10.6 ± 1.3 mm respectively. The mean values for AGDl, AGDu and AGR were 20.13 ± 4.04 mm, 39.2 ± 5.59 mm, and 0.51 ± 0.07, respectively. SPL less than 21 mm in a term male newborn and 17.5 mm in preterm should be considered micropenis (<2.5 SD) in our population. Gestation-wise percentile charts for SPL, PW, AGDl, AGDu and AGR were generated.

CONCLUSIONS

The reference values and percentile charts generated can serve as local normative data for accurate interpretation of genital measurements in North Indian newborns, assessment of ambiguous genitalia and avoiding diagnostic errors.

Micropenis

Micropenis, i.e., a structurally normal but abnormally small penis is defined as stretched penile length (SPL) 2.5 SD below the mean for age and sexual stage. Several studies worldwide have published country-specific normative data on SPL; an appropriate cutoff for evaluation of micropenis as per international standards would be below 2 cm at birth and below 4 cm after 5 y of age. Testosterone production by fetal testes, its conversion to dihydrotestosterone (DHT) and its action on the androgen receptor is necessary for normal penile development. Hypothalamo-pituitary disorders (gonadotropin or growth hormone deficiencies), genetic syndromes, partial gonadal dysgenesis, testicular regression, disorders of testosterone biosynthesis and action constitute the various etiologies of micropenis. Associated hypospadias, incomplete scrotal fusion, and cryptorchidism are suggestive of disorders of sex development (DSD). Along with basal and human chorionic gonadotropins (HCG)-stimulated gonadotropins, testosterone, DHT, and androstenedione levels, karyotype assessment is equally important. Treatment aims at attaining penile length sufficient enough for urination and to perform sexual function. Hormonal therapy with intramuscular or topical testosterone, topical DHT or recombinant follicle stimulating hormone (FSH) and luteinizing hormone (LH) should be attempted in the neonatal or infancy period. The role of surgery for micropenis is limited and has variable patient satisfaction and complication outcomes. There is a need for long-term studies on the adult SPL achieved following treatment for micropenis in infancy and childhood.

Penile Size in Term Newborns in Addis Ababa, Ethiopia

AIM

To determine the normative value of stretched penile length (SPL) for Ethiopian newborns and to set a cut-off point for micropenis.

METHODS

A total of 221 term newborns were included in the study. Stretched penile length was measured in the first 72 hours of postnatal age in neonates with a gestational age of 37-42 completed weeks. SPL < -2SD was taken as micropenis in this study.

RESULTS

The minimum and maximum penile length were 2.5cm and 5cm, respectively, with a mean ± SD of 3.28 ± 0.42. SPL at - 2 SD and + 2 SD were 2.43 and 4.12 cm, respectively. A significant correlation was observed between penile length and body length (p = 0.005). Neonates born via instrumental delivery had larger SPL compared to those who were delivered by caesarian section (p = 0.01) or by vaginal delivery (p = 0.006).

CONCLUSION

The mean stretched penile length in our study mirrors findings from other African studies. SPL less than 2.43 cm can be considered as micropenis in our setting. Therefore, routine genital examination and interpretation at birth is crucial to identify micropenis which might herald a serious underlying condition that needs further investigation.

Stretched penile length at birth: a systematic review

BACKGROUND

Micropenis is an endocrinological condition that is habitually observed at birth. Diagnosis is made by measuring the stretched penile length, a method established 80 years ago. Discrepancies in the normative data from recent studies raise the need for a current revision of the methodology.

OBJECTIVES

The aims of this systematic review were to compare the different normative data of SPL at birth, to examine the methodological aspects of the technique and to evaluate the independent variables that may be involved.

METHODS

Searches were performed using MEDLINE, EMBASE, Scielo, the Cochrane Library and Web of Science. A combination of the relevant medical terms, keywords and word variants for "stretched penile length", "penile length", "penile size", "newborn" and "birth" were used. Eligibility criteria included normative studies that used the stretched penile length (SPL) measurement on a population of healthy, full-term newborns during the first month of life. The outcomes studied included characteristics of the studies, methodological aspects and independent variables.

RESULTS

We identified 49 studies comprising 21,399 children. Significant discrepancies are observed between the different studies. Methodological aspects seem to be consistent and similar. The main independent variables appear to be ethnic group and gestational age. Main limitations were the absence of studies of entire world regions such as Europe or South America, and the heterogeneity of the ethnic background that complicates the analysis.

CONCLUSIONS

It seems advisable to suggest the creation of customized reference charts for each specific population instead of resorting to the classic cut-off points.

Sonographic measure techniques of fetal penile length

Postnatal penile length is a reliable, standardized, and widely used marker for the diagnosis of genitourinary pathology, as well as genetic and hormonal disorders. In contrast, prenatal diagnosis has not been developed equally and there is a lack of relevant literature. Our objective is to review the studies on fetal penile length, and apply findings to clinical practice. Although the most used technique is the outer penile length, there is no consensus regarding the appropriate technique for prenatal measurement. Several reports have provided reference data with high correlation. However, important issues like poor correlation with post-natal measures or presence of confounding variables are still present. Diagnosis of both a micropenis and macropenis can indicate related pathologies, and this information may benefit parental counseling and facilitate fetal management. Therefore, it is necessary to carry out prospective studies that provide reliable normative data.