Inclusion Criteria:  Women aged 21-40 years BMI 25-40 kg/m2 Intention to reside in Singapore for the next 4 years Chinese, Malay, Indian or any combination of these 3 ethnic groups Planning to conceive within 1 year Able to understand English Able to provide written, informed consent  Exclusion Criteria:  Currently pregnant Known type 1 or type 2 diabetes On any anticonvulsant medication in the past 1 month On any oral steroid in the past 1 month (e.g. Prednisolone, Prednisone, Deltasone, Prelone, Methyl Prednisolone, Medrol, Hydrocortisone, Cortef, Dexamethasone, Decadron) On any oral, implanted contraception or intrauterine contraceptive device (IUCD) in situ in the past 1 month On any fertility medication (e.g. hormones injection, IVF treatments) other than Clomiphene/ Letrozole in the past 1 month On HIV or Hepatitis B or C medication in the past 1 month.