SAN FRANCISCO -- Babies born with a congenital growth hormone deficiency (CGHD) are of normal length at birth and don't begin to experience growth problems until about six months of age, research by pediatricians at the University at Buffalo have found.
The work helps to answer the question of whether growth hormone deficiency interferes with fetal growth, said Margaret H. MacGillivray, M.D., UB professor of pediatrics, a pediatric endocrine specialist in the School of Medicine and Biomedical Sciences and at Children's Hospital of Buffalo and senior author on the study.
"People born with a growth hormone deficiency don't start out short," MacGillivray said. "Growth isn't affected until after they are out of the womb. It's at six to 12 months we really start to see children fail to grow."
Results of the research were presented here today (May 1, 1999) at the annual meeting of the Society for Pediatric Research.
Previous studies into the question of the effect of CGHD on fetal growth have produced conflicting results. The strength of this study, MacGillivray said, lies in the fact it involved children from a single regional medical center, Children's Hospital of Buffalo, all of whom had access to the same care. (One former study done by another researcher involved data from 12 countries).
In the UB study, researchers evaluated growth in 46 infants with clearly defined CGHD born between 1962 and 1997. All were full-term babies. Most had some type of medical problem at birth, predominately hypoglycemia (low glucose levels in the blood), hypoxemia (low oxygen levels) and/or jaundice.
Newborns are routinely screened at birth for hypoglycemia, which is a potential marker for CGHD, MacGillivray said. Babies who are hypoglycemic, or show other signs that something is wrong, are tested further. All 46 infants in this study required treatment for deficiencies in pituitary hormones. Babies who were hypoglycemic received early growth-hormone treatment, but their growth patterns were not different from the babies who didn't receive early growth hormone treatment.
"This study shows that birth length is not helpful in detecting infants who have congenital hypopituitarism," MacGillivray said. "Instead, persistence of hypoglycemia and jaundice are clues that should prompt an evaluation of hormones produced by the pituitary gland, i.e. growth hormone, thyroid- and adrenal-stimulating hormones. Replacing these hormones protects such infants from the long-term complications of hypoglycemia, such as seizure disorders and mental retardation.
"In addition, the study confirms that fetal growth is controlled by hormones other than growth hormone," she said. "The main influence on fetal growth is good nutrition, which depends on a healthy placenta and a healthy mother."
Additional researchers on the study were Susan Pena-Almazan, M.D., fellow in pediatric endocrinology/diabetes; John G. Buchlis, M.D., UB assistant professor of pediatrics; Susan Miller, a UB medical student, and Barbara J. Shine, nurse specialist.