Clinical Research Directory

Inclusion Criteria: * Women aged 18 to 45 years * Singleton pregnancy * A diagnosis of GDM from a 75-g OGTT during 24 to 28 gestational weeks, according to the IADPSG criteria, with at least fasting plasma glucose (FPG) ≥ 5.1 mmol/L * Intending to receive obstetric care and deliver in the study center * Willing and able to provide written informed consent and follow the study procedure Exclusion Criteria: * Use of melatonin 1 month before pregnancy or/and during pregnancy * Night shift work or exposed to jetlag on a regular basis during pregnancy * Contraindications to melatonin use, including hypersensitive or allergic to melatonin * Use of antidepressive or antipsychotic medications which can interfere with melatonin metabolism and/or elimination, such as fluvoxamine, 5- or 8-methoxypsoralen, cimetidine, quinolones, and other CYP1A2 inhibitors; carbamazepine, rifampicin, and other CYP1A2 inducers; and zaleplon, zolpidem, zopiclone, and other non-benzodiazepine hypnotics * Pre-pregnancy diabetes, including patients diagnosed with diabetes before conception, fasting plasma glucose ≥ 7.0 mmol/L or HbA1c ≥ 6.5% in the first trimester, typical hyperglycemic symptoms or hyperglycemic crisis with random blood glucose ≥ 11.1 mmol/L * Other major diseases before gestation, e.g. hypertensive disorders, rheumatology or malignant diseases, infected with hepatitis B or hepatitis C, chronic diseases leading to impaired heart, liver, or renal function * Major fetal anomalies