title: Characteristics of boys with the so-called true undescended testis diagnosed at the third postnatal month--a population-based case-control study.
abstract: OBJECTIVE
  Undescended testis (cryptorchidism) is a common congenital abnormality of male genital organs diagnosed at birth followed with frequent postnatal descensus. However, the so-called isolated true undescended testis (ITUT) diagnosed at the third postnatal month seems to be an independent defect-entity, and this hypothesis was planned to confirm or reject in the study.
  
  
  METHODS
  The evaluation of birth outcomes and maternal socio-demographic data of cases with ITUT in the population-based large dataset of the Hungarian Congenital Abnormality Registry.
  
  
  RESULTS
  There was a higher rate of preterm birth and particularly of low birthweight in 2052 cases with ITUT compared to 24,814 population male controls without any defects. The rate of twins was not higher in cases with older mothers, higher birth order and lower socio-economic status. The comparison of data of boys with undescended testis diagnosed at birth found in the previous study and with ITUT in this study confirmed our hypothesis.
  
  
  CONCLUSIONS
  Undescended testis can be differentiated into two subgroups: boys with frequent postnatal descensus mainly after preterm delivery and boys with ITUT without postnatal testis descensus with frequent intrauterine growth restriction, older mothers with higher birth order and low socio-economic status.
authors: a Department of Uro-oncology , National Institute of Oncology , Budapest , Hungary .
authors: Stelios
authors: S
authors: Mavrogenis
authors: Robert
authors: R
authors: Urbán
authors: Andrew E
authors: AE
authors: Czeizel
mesh_terms: D016022:Case-Control Studies; D003456:Cryptorchidism / Q000175:diagnosis* / Q000453:epidemiology; D005260:Female; D006801:Humans; D006814:Hungary; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D008297:Male; D011247:Pregnancy; D047928:Premature Birth; D012042:Registries; D012307:Risk Factors
keywords: Birth order; low birthweight; maternal age; population based case–control study; preterm birth; socio-economic status; undescended testis (cryptorchidism)