NEW YORK (AP) — U.S. birth rates declined last year for women in their teens, 20s and — surprisingly — their 30s, leading to the fewest babies in 30 years, according to a government report released Thursday. Experts said several factors may be combining to drive the declines, including shifting attitudes about motherhood and changing immigration patterns. The provisional report, based on a review of more than 99 percent of the birth certificates filed nationwide, counted 3.853 million births last year.