Pregnant women already have plenty to worry about. But now some doctors are pointing to another potential problem: tattoos.

The issue is whether it's safe to stick a needle through a tattoo in the lower back for an epidural -- an injection of painkilling medicine that can ease the discomfort of labor.

There has been an explosion in recent years in women's lower-back tattoos -- often ornate designs that take up a lot of surface area near the vertebrae where epidural needles are typically inserted.

In 2002, a pair of Canadian anesthesiologists published a report that questioned whether administering an epidural through such a tattoo could be risky. The doctors speculated that complications like inflammation or nerve damage may arise if the needle pulled a bit of dyed skin along with it, and then deposited it into the nerve-rich region outside the spinal column.

The small study of three women -- which concluded that there wasn't enough evidence to determine if the practice is safe or not -- set off a mini-wave of panic among expectant moms. After the report was picked up by Canadian television, women began sharing their concerns on pregnancy Web sites and chat rooms. In July, a story on the topic appeared in Pregnancy magazine, further fueling anxiety and sending many women to their practitioners for advice.