MENTAL HEALTH TREATMENT AND METABOLIC DISORDERS IN PREGNANCY: A LONGITUDINAL STUDY Objective: This study aimed to measure sequential rates of obesity, gestational diabetes, polycystic ovary syndrome, and anxiety, depression, and antidepressant treatment in pregnant women in Australia between 2008 and 2022. Materials and Methods: BMI ≥ 30 (obesity), BMI ≥ 35 (severe obesity/obesity class II and III), gestational diabetes, Type II diabetes, polycystic ovary syndrome, clinical diagnoses of anxiety and depression, antidepressant treatment. Results: Women taking antidepressants in pregnancy were substantially more vulnerable to obesity (BMI ≥ 30) with rates of 43.59% vs 26.00%. Women taking antidepressants in pregnancy also had higher rates of severe obesity (BMI ≥ 35) at 25.63% vs 12.98%. A small minority of these women were also nearly 6 times more likely to drink alcohol in pregnancy (2.7% vs 0.47%) and to use other drugs in pregnancy such as amphetamines (0.35% vs 0.07%) and cannabis (3.4% vs 0.73%). When compared with peers matched for diagnoses of depression and anxiety, women taking antidepressants were still more likely to be obese (25.63% vs 20.17%) though this difference was not so marked. Rates of obesity have increased in the cohort studied from 26.86% to 31.27%; of gestational diabetes from 3.98% to 21.77%; of polycystic ovary syndrome from 1.47% to 5.47%; of anxiety from 1.11% to 5.77%; of depression from 2.17% to 4.31%, and antidepressant treatment from 1.45% to 2.16%. Conclusions: Obesity, gestational diabetes and polycystic ovary syndrome rates have substantially increased between 2008 and 2022 in Australia. Rates of anxiety in pregnant women have increased substantially over this period, as have rates of depression. Women living with depression and anxiety in pregnancy are increasing to suffer obesity and related metabolic conditions. Antidepressant treatment may also increase these women’s vulnerability to obesity and severe obesity. ASEAN Journal of Psychiatry, Vol. 25 (7) July, 2024; 1-10.