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NCT Number: NCT07369284

Melatonin for Glycemic Control in Gestational Diabetes Mellitus

The goal of this randomized, double-blind, placebo-controlled clinical trial is to evaluate whether melatonin supplementation improves glycemic control in pregnant women diagnosed with gestational diabetes mellitus (GDM).

The main question it aims to answer is:

Does melatonin supplementation help with glycemic control, especially in lowering fasting plasma glucose level?

Researchers will compare melatonin to a placebo (a look-alike substance that contains no melatonin) to see if melatonin works to improve glycemic control.

Participants will:

1. Take melatonin or a placebo every day after randomization until delivery 2. Visit the antenatal clinic once every 1 to 2 weeks for follow-ups

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Key information

Conditions

Gestational Diabetes Diabetes Mellitus Diabetes, Gestational Endocrine System Diseases Female Urogenital Diseases and Pregnancy Complications Glucose Metabolism Disorders Metabolic Diseases Nutritional and Metabolic Diseases Pregnancy Complications Urogenital Diseases

Age range

18 year–45 year

Sex eligibility

Female

Study type

Interventional

Phase

Phase 2

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Melatonin

Drug
  • Melatonin tablets will be administered orally 0.5 to 1 hour before sleep and at least 2 hours after the last meal.
  • Participants will take 5 mg melatonin every night during the first week of intervention after randomization, followed by 10 mg melatonin every night from the second week until delivery.

Placebo

Other
  • Identical placebo tablets in terms of packaging, appearance, smell and taste will be administered orally 0.5 to 1 hour before sleep and at least 2 hours after the last meal.
  • Participants will take identical placebo tablets after randomization until delivery.

Primary outcomes

  1. Change in fasting plasma glucose (FPG) from baseline to 36 to 38 gestational weeks

    Time frame: Baseline (24 to 28 gestational weeks), and 36 to 38 gestational weeks

    The primary outcome is defined as the change in FPG levels from baseline, measured at the time of OGTT performed between 24 and 28 gestational weeks, to follow-up assessment at 36 to 38 gestational weeks. For participants who deliver before 36 gestational weeks, the last available FPG measurement obtained will be used.

Secondary outcomes

  1. Change in glycated hemoglobin (HbA1c) from baseline to 36 to 38 gestational weeks

    Time frame: Baseline and 36 to 38 gestational weeks

    This outcome is defined as change in HbA1c levels from baseline, measured at the time of OGTT performed between 24 and 28 gestational weeks, to follow-up assessment at 36 to 38 gestational weeks.

  2. Initiation of insulin therapy

    Time frame: From baseline until delivery

    This outcome is defined as the proportion of participants requiring initiation of insulin therapy.

  3. Change in mean glucose levels assessed by continuous glucose monitoring (CGM)

    Time frame: Baseline and 36 to 38 gestational weeks

    This outcome is defined as the change in mean glucose levels measured by CGM at baseline and before delivery.

  4. Gestational weight gain in late pregnancy

    Time frame: From baseline until delivery

    This outcome is defined as total gestational weight gain and the rate of weight gain from baseline to the last assessment prior to delivery.

  5. Incidence of intervention-related adverse events

    Time frame: From initiation of the intervention until 6 weeks postpartum

    This outcome is defined as the proportion of participants reporting adverse events potentially related to study intervention, including but not limited to dizziness, hypersomnia, nausea, vomiting and hypoglycemia. Adverse events will be collected from participants' medication diaries and systematically assessed through participant self-report at each antenatal clinic visit.

  6. Impact of melatonin on fetal growth

    Time frame: From baseline until delivery

    The antenatal use of melatonin on estimated fetal growth (grams) will be assessed using ultrasound biometry parameters performed every two to four weeks following trial recruitment until birth.

  7. Percentage of time in range, time above range, and time below range measured by CGM

    Time frame: Baseline and 36 to 38 gestational weeks

    This outcome is defined as percentages of time in range, time above range, and time below range measured by CGM at baseline and before delivery.

Other outcomes

  1. Pregnancy complications

    Time frame: From baseline until the end of follow-up at 6 weeks postpartum

    This outcome is defined as a series of pregnancy complications including but not limited to gestational hypertensive disorders and intrahepatic cholestasis of pregnancy.

  2. Perinatal outcomes

    Time frame: From baseline until the end of follow-up at 6 weeks postpartum

    This outcome is defined as a series of perinatal outcomes including but not limited to the percentages of macrosomia, large for gestational age, small for gestational age, neonatal hypoglycemia, birth trauma, cesarean section, postpartum hemorrhage, placenta abruption, and spontaneous premature rupture of membranes.

Study contacts

Contact information is provided by the study sponsor or research team.

Yanting Wu, PhD

CONTACT

[email protected]

8621-17321218018

Sponsors and collaborators

Lead sponsor

Obstetrics & Gynecology Hospital of Fudan University

Other

Collaborators

  • West China Second University Hospital

Registry information

Official study title

Efficacy of Melatonin in Addition to Standard Care in Glycemic Control of Patients With Gestational Diabetes Mellitus: a Randomized, Double-blind, Placebo-controlled Trial

Acronym: MELODY

Important dates

Study start
2026
Primary completion
2027
Study completion
2027
First posted
Jan 27, 2026
Registry last updated
Jan 27, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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