Roe v Wade's trimester system, like virtually all abortion cutoffs, was essentially arbitrary. Calibrated to fit what their gut felt was right. For evidence

Roe v Wade's trimester system, like virtually all abortion cutoffs, was essentially arbitrary. Calibrated to fit what their gut felt was right. For evidence of this, look at the abortion cutoffs in Europe, nearly every European country has a different cutoff from the others. In Germany it's 12 weeks and in the UK it's 24. It's all over the place. If these cutoffs were based on science there shouldn't be this much spread.