THURSDAY, April 27, 2017 (HealthDay News) -- After having one baby and tending to the infant's dirty diapers and middle-of-the night wails, you'd think that most teens would want to wait awhile before having a second baby.
But, a new U.S. government report finds that's not always the case. Instead, tens of thousands of American teens are getting pregnant for a second time.
Most teens do seem to be trying not to have another child. Still, about 17 percent of teen moms aren't using any form of birth control, according to the U.S. Centers for Disease Control and Prevention (CDC).
"These data suggest that most teen mothers are taking steps to prevent another pregnancy, but one in three is using either a least-effective method or no contraception at all," said lead researcher Deborah Dee, an epidemiologist in CDC's division of reproductive health.
The CDC study defined the least-effective forms of birth control as: condoms, diaphragms, cervical caps, contraceptive sponges, rhythm method/natural family planning, the "morning-after pill," and withdrawal.
The most-effective contraceptives are those that do not depend on having to remember to use them, said Dr. Jennifer Wu, an ob-gyn at Lenox Hill Hospital in New York City. These include intrauterine devices (IUDs) and implants, which are always at work.
Wu said that today's IUDs are safer and more effective than those of decades ago. IUDs or implants can be put in place before the patient leaves the hospital after having a baby, she said.
The least-effective methods of birth control are those that someone has to make a conscious effort to use, Wu said.
The good news is that overall teen pregnancy rates have dropped by nearly two-thirds in the past 25 years in the United States, the study authors said.
And fewer teens are having second babies. In 2015, one in six births to teens aged 15 to 19 was a repeat birth, a significant decline from 2004, when one in five births was a second birth, the researchers found. In 2015, more than 38,000 teen moms had a second child.
Second babies of teen moms are more likely than the first child to be born preterm and underweight, the authors noted.
"I'm happy to see that repeat births among teens have gone down significantly, but it's still way too high," Wu said.
These second pregnancies can be attributed to teens not using effective birth control after their first baby, she added.
In 2013, about 25 percent of teen mothers used one of the most-effective methods of contraception (one with a failure rate of less than 1 percent), which was about five times higher than in 2004, the findings showed.
The percentage of teen moms who reported using a most-effective method of birth control ranged from 11 percent in New York City to 52 percent in Colorado. And the percentage of those not using any method ranged from 5 percent in Vermont to 34 percent in New Jersey.
For a teenager, having a second child compounds the problems of having a first infant, Wu said.
"Teenagers are not financially, emotionally, sometimes not even physically able to take care of babies," she said. "When a teenager has two babies, they can really derail themselves in terms of education and job choices."
From 2004 to 2015, the researchers found that 35 states experienced a significant decline in the percentage of teen births that were repeat births. Among the 35 states, a dozen had declines of more than 20 percent. None had a significant increase.
The largest declines in repeat teen births were among blacks (22 percent), followed by Hispanics (17 percent), and whites (14 percent), according to the report.
Dr. Jane Swedler is chief of adolescent medicine at NYU Winthrop Hospital in Mineola, N.Y. "It is extremely encouraging that over the last 10 years there has been a rapid decline in teen births [by nearly 54 percent]," she said.
"To further reduce teen birth, as well as repeat teen births, it is imperative to institute comprehensive, adolescent-friendly services that promote health education and offer accessible, affordable and effective contraception options to teens," Swedler said.
The report was published in the April 28 issue of the CDC's Morbidity and Mortality Weekly Report.
For more about teen pregnancy, visit the U.S. Centers for Disease Control and Prevention.