At least 5% of women have an eating disorder (ED) during pregnancy. These EDs affect prepregnancy body mass index (BMI) and weight gain during pregnancy, factors associated with birth complications and adverse neonatal outcomes. This review contributes to the literature by examining several adverse birth outcomes associated with EDs and differentiates between past and present EDs. Of the 18 articles reviewed, EDs were associated with preterm birth in 5/14 (36%) and small-for-gestational-age in 5/8 (63%) studies. Anorexia Nervosa increases the odds of a low birth weight baby, particularly when women enter pregnancy with a low BMI. Binge Eating Disorder is positively associated with having a large-for-gestational-age infant, and Bulimia Nervosa is associated with miscarriage when symptomatic during pregnancy. Having a current ED increases the risk for adverse birth outcomes more than a past ED. Since the aetiology of adverse birth outcomes is multi-factorial, drawing conclusions about causal relationships between EDs and birth outcomes is problematic given the small number of studies reporting these outcomes. Resources should target preconception interventions that put EDs into remission and help women achieve a healthier BMI prior to pregnancy, as these have been consistently shown to improve birth outcomes.