Yes, according to Dr. Laura Riley, an obstetrician and director of labor and delivery at Massachusetts General Hospital. In general, the lowest risk pregnancies are those in women between 25 and 35. At the extremes of age — teenagers and women 40 and over, the rate of pregnancy complications rises.

Among other things, said Riley, teenage women are at higher than normal risk for pre-eclampsia, high blood pressure in pregnancy that, if untreated, can lead to coma and death. The treatment is often to induce labor because once the baby is born, the mother’s blood pressure usually returns to normal.

Teen mothers are also more at risk for pre-term delivery because “teenage girls are more likely to have the worst diet in the world, make poor food choices, smoke, have more stress, and are less likely to be married,” she said.

One reason that babies of teenage mothers often have low birth weight is that what few nutrients they do eat go to nourish their own growing bodies, not their fetus’. As Columbia University researchers wrote in a study this year in the American Journal of Obstetrics and Gynecology, “much of the maternal nutrient intake supports maternal growth, to the detriment of the developing fetus.”

The good news is that teenage pregnancy and birth rates have dropped by one-third since the early 1990s in all states and among all racial and ethnic groups, said Bill Albert, spokesman for the National Campaign to Prevent Teen Pregnancy, a private, nonprofit, nonpartisan group based in Washington, D.C. Research suggests that this is due to teenagers delaying sex and using contraception more reliably.