Monitoring Nutritional Consequences of Obesity Treatment on Women's Health

General Inclusion Criteria: * Female sex at birth * Aged 18-55 years of age * Living with obesity (BMI ≥ 30 kg/m2) * Approved for obesity treatment in one of the participating hospitals: * Undergoing primary bariatric surgery (RYGB, OAGB or SG) * Receiving obesity medication (any type) with a BMI ≥30 kg/m2 under medical supervision. * For those undergoing MRI, DEXA and quantitative ultrasound scan: Willing to be informed about incidental findings of pathology and approving of reporting this to their general physician. Additional inclusion criteria for birth cohort: * Being pregnant * Age 18-45 years of age * Having received prior obesity treatment, either surgical (RYGB, OAGB, SG) or pharmacological for at least 4 months under medical supervision (any type). General Exclusion Criteria: * Male sex at birth * Aged \<18 or \>55 years of age * BMI \<30 kg/m2 * Not able to read and/or write in Dutch * Undergoing a revisional or secondary bariatric procedure (excluding previous gastric banding) * Malnutrition due to other chronic condition, specifically malignancy, substance abuse * (mental) condition that makes it impossible to fill out a questionnaire correctly. * For those undergoing a DEXA scan: height \>196 cm or weight \>160 kg * For those undergoing a MRI scan: having a contra-indication to MRI scanning including (but not limited to) pacemakers and defibrillators, intraorbital or intraocular metallic fragments, ferromagnetic implans or claustrophobia. Additional exclusion criteria birth cohort: * Aged \<18 or \>45 years of age * \>25 weeks of gestation * Multiple pregnancy * Reversal of the bariatric procedure