Births to teen mothers are now at a record low in the United States, the National Center for Health Statistics reports in Monday’s issue of the journal Pediatrics. The new rate: 31.3 births per 1,000 girls and women aged 15 to 19.

“There is lots of good news in the report,” said Brady Hamilton, a statistician at the NCHS who led the study.

It’s good news because such births are almost always unplanned and the parents are rarely ready to cope with the responsibility of raising a baby. Teenaged moms are also more likely to have babies of a smaller-than-healthy weight or to have stillborn babies.