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Hypospadias and early gestation growth restriction in infants
Naveed Hussain1, Azhar Chaghtai, C D Anthony Herndon
1Division of Neonatology, Department of Pediatrics, University of Connecticut Health Center, Farmington, Connecticut 06030-2948, USA. hussain@nso1.uchc.edu
Insights
Hypospadias incidence has risen tenfold, strongly linked to poor early intrauterine growth. This suggests common environmental factors may impact both infant conditions.
Area of Science:
- Pediatric Urology
- Neonatology
- Public Health
Background:
- Hypospadias incidence has significantly increased in recent decades.
- Risk factors for hypospadias remain largely unknown.
- Previous studies suggest a possible link between low birth weight and hypospadias.
Purpose of the Study:
- To investigate the association between early gestation intrauterine growth and hypospadias.
- To analyze trends in hypospadias incidence over a 13-year period.
Main Methods:
- Retrospective review of 6746 male infants admitted to two tertiary care neonatal intensive care units (NICUs) from 1987-2000.
- Analysis of infant growth parameters (birth weight, length, head circumference) and maternal risk factors.
- Exclusion of infants with genetic syndromes (n=8).
Main Results:
- Hypospadias incidence in the NICU population increased tenfold (0.4% to 4%) between 1987 and 2000.
- Significantly higher hypospadias rates observed in infants with poor intrauterine growth (<10th percentile) across all measured parameters.
- First-born infants showed a higher frequency of hypospadias compared to subsequent births.
Conclusions:
- A significant association exists between hypospadias and poor intrauterine growth, likely originating in early gestation.
- The proportionate impact on somatic and brain growth suggests a common etiological pathway.
- Increasing hypospadias rates and poor growth indicate potential involvement of shared environmental factors.
Objective:
There has been a major increase in the incidence of hypospadias in infants in the 1990s, but the risk factors are not known. Although there are scattered reports in the literature regarding the association of low birth weight and hypospadias, this has not been systematically studied. The objective of this study was to determine the association between early gestation intrauterine growth and hypospadias.
Methods:
A retrospective review of 13 years of admissions to 2 tertiary care neonatal intensive care units (NICUs) in Connecticut (1987--2000) showed that 112 (1.66%) of 6746 male infants had any degree of hypospadias. Of these, 8 were part of a genetic syndrome and were excluded. A retrospective cohort analysis of these 6738 infants was performed. Infant growth parameters at birth (weight, head circumference, and length) were analyzed along with maternal risk factors known to be associated with changes in fetal growth, including maternal age, race, diagnosis of preeclampsia, gestational diabetes, and maternal use of alcohol or tobacco or substance abuse during pregnancy.
Results:
The incidence of hypospadias in the NICU population increased 10-fold from 0.4% in 1987 to 4% in the first quarter of 2000. Hypospadias was significantly more common in infants who had uniformly poor intrauterine growth (<10th percentiles) in the various parameters measured: birth weight, length, or head circumference. There were no significant differences in maternal age or race, nor were there differences in the use of alcohol, tobacco, or street drugs by the mother. There were no differences between singletons and multiple-gestation births. However, the frequency of occurrence was significantly higher among first-born infants (1.9%) compared with all other infants (0.9%).
Conclusions:
The incidence of hypospadias in our NICU population has increased 10-fold during the 13-year period of study. There was a significant association of hypospadias with poor intrauterine growth. The growth restriction was probably of early gestational cause as there was proportionate involvement of somatic (weight and length) and brain growth (head circumference). The increasing frequency of hypospadias and its association with poor intrauterine growth originating in early gestation suggests that common environmental factor(s) that have an impact on both conditions may be involved.