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Plain Dealer, February 10, 2009

Bone Health vs. Birth Control

By Angela Townsend

Cleveland -- As if the idea of a teenage daughter using (or not using) birth control isn't stressful enough, parents have another thing to mull over. A recent study headed up by MetroHealth Medical Center physicians underscores the importance of pick-ing the right contraceptive.

The study, published in the December 2008 issue of Fertility and Sterility (the official journal of the American Society for Reproductive Medicine), showed a slight loss in the bone-mineral density of teenage girls on Depo-Provera, a natural hormone used for birth control that is injected in the upper arm or in the buttock every three months.

On the flip side, girls in the study who took low-dose estrogen birth-control pills or who weren't on any birth control gained bone density.

All of these girls were healthy to begin with. Thus, the results of the study underscore the concern for girls with certain medical conditions who are using Depo-Provera. It's easy to say that girls wouldn't have to worry about bone mineral density if they just "said no" to sex. But there's no getting around that teens are sexually active.

Teen birth rates are going down nationally and in the city of Cleveland, but the latest figures available still show that Cleveland teens ages 14 to 19 ac-counted for 68 per every thousand births in 2005. That's higher than the national teen birth rate of 40.5 per thousand for the same year.

Sexually active teens looking to avoid pregnancy do have birth-control choices. Thus the dilemma when it comes to Depo-Provera.

It's the ideal contraceptive because it's foolproof. It protects from preg-nancy immediately after the first injection. Within a year of starting the shots, a woman's period stops completely. There are no pills to remember, no cumbersome contraceptive device to insert. But then there's the issue of bone-density loss.

At the end of adolescence, women reach peak bone mass. That stays until we're in our 30s, and it drops fast once menopause begins. The higher the bone mass at its peak, the better chance of staving off osteoporosis at menopause.

The two-year study led by Dr. Barbara Cromer, a pediatrician and director of adolescent medicine at MetroHealth, started out tracking 433 healthy girls who were patients at MetroHealth, Rainbow Babies & Children's Hospital, the Cleve-land Clinic Children's Hospital and the Free Medical Clinic of Greater Cleve-land.

Fifty-eight girls were given Depo-Provera, while 187 were given the low-dose pill and 188 were not prescribed any birth control.

At the end of the study, 42 percent of the original girls were still partici-pants.

Two years worth of monitoring revealed that one-third of girls on Depo-Provera in the study lost a small amount of bone density. That degree of loss slowed after one year. That alone isn't too alarming because other research has shown that bone mass can be regained quickly when the shots are discontinued.

With that in mind, healthy adolescents can start and use the shot without concern, for a short amount of time, Cromer said.

But girls should think twice before going on Depo-Provera if they are very thin and/or have an eating disorder; are physically immobile; or have a disease or are taking medications (certain drugs for epilepsy, or long-term high-dose steroids, for example) that can harm the bones, Cromer said.

Girls with these conditions "should ask their doctor if perhaps a DEXA scan [a bone-density scan] might be considered [to see] where they are," she said. "If they have a very low bone mass, another birth control method might be con-sidered."

The warning about the potential weakening of bones while on Depo-Provera is on the drug's Web site (www.depoprovera.com). In 2004, the Food and Drug Admini-stration issued a "black-box" warning for the drug that highlighted that risk if used for longer than two years.

For those who think the answer to protecting a girl's bone density is to keep her far away from birth control of any kind, keep this in mind: A developing fe-tus also has an impact on an adolescent's bone health as it steals calcium stored in the bones.

Risking that alternative instead of using effective contraceptives "is not a good trade-off," says Cromer.

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