Birth Length and Weight in Congenital Adrenal Hyperplasia

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This Italian study looked retrospectively at birth length and weight of infants with congenital adrenal hyperplasia (CAH) and compared these parameters with standards for birth length and weight in a contemporary Italian control population. In addition, the authors evaluated whether or not neonatal auxilogical data may change depending on the different clinical forms of CAH. The study population included 101 Italian infants (40 boys) with different forms of CAH. Forty-seven of these (10 boys) had non-classical CAH and the remaining 54 (30 boys) had one of the classical forms, either salt wasting (40 patients; 23 boys) or simple virilizing (14 patients; 7 boys). Only those children with available birth weights and lengths and with a gestational age ranging from 38 to 41 weeks were selected. None of these children had received steroid treatment during fetal life. The phenotype classification was based on clinical and hormonal data for the salt-wasting form. These criteria included failure to thrive, vomiting, diarrhea, hyponatremia, hyperkalemia, and ambiguous genitalia in females. All had extremely elevated levels of 17 hydroxyprogesterone. For the simple-virilizing form, the criteria included ambiguous genitalia in the females, sexual precocity, acceleration of height and bone age development, and elevated 17-hydroxyprogesterone. The control population was represented by 28,274 live births with a gestational age of 39 weeks for girls and 40 weeks for boys.

Both birth weight and length were significantly greater in the group of infants with classical CAH than in the group of those with non-classical. When the subjects were classified into males and females, the differences were significant for boys and girls. The birth data of girls and boys with classical CAH were compared with national birth data. Both the weights and lengths were significantly greater in girls whereas the boys were only longer, but not heavier than their controls.

The authors stated that these studies demonstrate for the first time that 21- hydroxylase deficiency is able to affect fetal growth only in those cases with severe, prenatal onset of hyperandrogenism. Those with the salt wasting form were longer than those with the simple virilizing form. This may reflect greater androgen activity early in gestation. The authors concluded that fetal length and velocity in CAH may be increased only in infants with classical forms while unaffected in those with non classical forms. They also suggested that the greater enzymatic activity impairment, the longer the newborns with CAH.

Balsamo A, Wasniewska M, Di Pasquale G, et al. Birth length and weight in congenital adrenal hyperplasia according to the different phenotypes. Eur J Pediatr. 2006;165:380–383.

Editor’s Comment

This is an intriguing manuscript and while the data may not be surprising they do suggest possible ways of monitoring androgen activity in fetuses diagnosed prenatally with CAH. Unfortunately, there are no data with regard to premature infants. Current neonatal screening tests for CAH have a significant number of false-positive results in pre-term infants. An additional axiological identifier of androgen excess during fetal life may be of benefit. Data from the current study clearly demonstrate the effect of androgens on fetal growth and should be of interest to all pediatric endocrinologists and perinatologists. Interestingly, the authors apologize for the small number of infants studied. However, this editor applauds their efforts in identifying and carefully extracting the data on what this reviewer considers a relatively large number of subjects.

William L. Clarke, MD

Last Updated: 04/30/2008