Urinary tract malformations in the Department of Obstetrics of the University of Chile Clinical Hospital, in the period 1982-1997

Background: The prevalence of urinary malformations at birth is steadily in creasing probably due to the availability of better diagnostic techniques. Aim: To assess the prevalence of renal agenesis, hidroureteronephrosis and polycystic kidney at birth in the obstetric wards of the University of Chil e Clinical Hospital. Patients and methods: As a part of the Latin American Collaborative Study of Congenital Malformations, 54,039 consecutive births at the Maternity, between January 1982 and December 1997, were studied. Res ults: Eighty three newborns had urinary tract malformations (15.3/10000). F ourteen (2.6/10000) had renal agenesis. 34(6.3/10000) had hidroureteronephr osis and 35(6.5/10000) had polycystic kidney. Eleven percent of these child ren were stillbirths and 35% died in the first days of life. Fifty six perc ent were male, 34% female and 10% had ambiguous sex. Mean birth weight was 2750g, mean gestational age was 35.4 weeks and mean maternal age was 28 yea rs old. Twenty three percent of mothers had a history of previous abortions , 8% had a history of stillbirths and 10% a history of metrorrhagia during the first trimester of pregnancy. Twenty five percent of children had a rel ative with a malformation and 48 children had other associated malformation s such as pulmonary hypoplasia, external malformations caused by extreme ol igoamnios or internal malformations such as utereral, urinary bladder, uret ral or external genitalia agenesis. Conclusions: The prevalence of urinary malformations in this hospital was higher than in other hospitals participa ting in the collaborative study. This difference could be to an under regis tration of malformations in other hospitals.