Just putting them out there for reference and discussion.
While there was a substantial drop in the pregnancy rate for 15–17-year-olds and 18–19-year-olds between 2008 and 2010, pregnancies among 18–19-year-olds constituted the majority (69%) of teen pregnancies. During this same time period, increasing proportions of 18–19-year-olds reported having ever had sex, yet fewer of them became pregnant. The likely reason is improved contraceptive use and use of more effective methods.
If teens are more likely to have sex, that’s a reversal of the recent trends reported by a paper in Pediatrics:
The statistical significance of this relationship survives controlling for mean income (more religious states tend to have lower mean income), and, of course controlling for abortion rates (if states with higher religiosity have lower abortion rates then higher teen birth birth rates would not necessarily be a surprise).
I’d also highly recommend this post from Slate Star Codex on abortion and contraception usage.