direct from the article "Only a small proportion of abortion patients (10%, not shown) reported that they had never used contraception, and in the multivariable model these women were less likely to report that they had a prior abortion (OR: 0.81; 95% CI: 0.67–0.97). However, this association was tenuous as it was not significant in either of the models generated for sensitivity analyses (not shown)."
So the majority of these pregnancies were caused due to failed contraception and not the main source of contraception like JT is saying