The BBC says a Swedish study of premature infants finds 70 percent of infants born between 22 and 26 weeks (the latter part of the second trimester) survive past the age of 1. This has implications for abortion rights here.
It's not just because the anti-abortion movement will seek to use this information and medical advances in service to its political agenda, either. It's because Roe v. Wade specifically makes reference to fetal viability as the point at which states are allowed to more stringently restrict a woman's right to obtain an abortion, including prohibiting her from doing so if there's an except for her life and health.
(a) For the stage prior to approximately the end of the first trimester, the abortion decision and its effectuation must be left to the medical judgment of the pregnant woman's attending physician.
(b) For the stage subsequent to approximately the end of the first trimester, the State, in promoting its interest in the health of the mother, may, if it chooses, regulate the abortion procedure in ways that are reasonably related to maternal health.
(c) For the stage subsequent to viability, the State in promoting its interest in the potentiality of human life [410 U.S. 113, 165] may, if it chooses, regulate, and even proscribe, abortion except where it is necessary, in appropriate medical judgment, for the preservation of the life or health of the mother.
In other words, states cannot interfere with the manner in which women choose to have abortions during the first trimester; they are allowed regulatory powers (but can't ban the procedures outright) during the second trimester until fetal viability; and they can prohibit them after viability if they want, as long as there's an exception for the life and health of the mother. When viability can be expected between 22 and 26 weeks, the first-second-third trimester distinctions that currently hold sway in most people's minds when they think of abortion are rather limited.
And if you think the anti-abortion groups won't get around to challenging Roe and trying to push for new legislative restrictions or eliminations on second trimester abortions, you haven't been paying attention very well.