Parents considering treatment for this otherwise medically benign illness should know what it involves : daily injections for years before the child ’s growth is completed, rotating injection sites in the body to minimize scarring. Although few children experience side effects, which can include severe headaches and hip issues, treatment requires repeated doctor visits, X-rays and blood work and, Dr. Grimberg said, “gives the child a powerful message that there’s something wrong with him that needs fixing. ”

According to the Pediatric Endocrine Society, the decision to administer growth hormone for idiopathic short stature should be made on a case-by-case basis in which benefits and risks are carefully considered for each child.

What, then, are the benefits and risks? Although producers have supported monitoring drug safety beyond the 10 years mandated by the U.S. government, reporting is voluntary and necessarily incomplete. But a far more reliable assessment can be found from Sweden, where population-wide data are routinely collected.

In JAMA Pediatrics in December, pediatric endocrinologists in Karolinska University Hospital reported that among 3,408 patients that were treated with recombinant growth hormone as children and adolescents and followed for up to 25 years, the risk of developing a cardiovascular event like a heart attack or stroke was two-thirds higher for men and twice as large for girls than among 50,036 untreated but otherwise similar people.

The Swedish finding follows a report last June from a research team in Tokyo that growth hormone promotes biomedical pathways that stimulate the development of atherosclerosis, the basis for many cardiovascular events.

Not yet known is whether other long-term negative effects will become evident in the years ahead. According to its known activity, giving growth hormone when no deficiency exists might raise the risk of cancer, respiratory disease and diabetes. In an editorial in JAMA Pediatrics, Dr. Grimberg wrote that “indirect evidence suggests that the possibility of untoward effects of growth hormone therapy is sufficiently plausible” to justify further study.

Equally important for parents to know is how much height their kids might gain from years of daily hormone injections. Though impossible to predict in advance for an individual child, the average benefit for children with idiopathic short stature is about two inches in adult height. Dr. Grimberg suggested that if there’s no measurable benefit in a year of treatment, parents should consider stopping it.