Could women who had anorexia in the past still get pregnant?

Yes: Yes provided she is getting a period once a month.

With caution: Infants of women with anorexia have lesser birthweight , smaller head circumferences and a 16% rate of microcephaly compared to control patients, due to less maternal pregnancy weight gain, increased nausea/ vomiting of pregnancy, and increased recurrence of anorectic symptoms. Unintended pregnancy /early pregnancy loss are increased. Prepregnancy evaluation by a clinical team is critical!

Potentially : I would make sure you are followed by a obstetrician for any concerns; before, during, and after pregnancy.