Home » Trials » SLCTR/2018/020

A Randomized Control Trial comparing vitamin D supplementation versus placebo on glycemic control in gestational diabetes mellitus


SLCTR Registration Number


Date of Registration

25 Jun 2018

The date of last modification

Mar 03, 2019

Application Summary

Scientific Title of Trial

A Randomized Control Trial comparing vitamin D supplementation versus placebo on glycemic control in gestational diabetes mellitus

Public Title of Trial

A randomized controlled clinical trial to compare the efficacy of Vitamin D vs placebo to reduce high blood sugar during pregnancy

Disease or Health Condition(s) Studied

Gestational diabetes

Scientific Acronym


Public Acronym


Brief title


Universal Trial Number


Any other number(s) assigned to the trial and issuing authority

(Ref. No. P/277/12/2017: ERC Kelaniya)

Trial Details

What is the research question being addressed?

Is there an effect of Vitamin D on improving glycemic control in gestational diabetes?

Type of study


Study design


Randomized controlled trial


Double blinded







Study Phase

Phase 4

Intervention(s) planned

Study site is the antenatal clinic of the Colombo North Teaching Hospital, Ragama.

Block randomization will be done using a computer generated sequence using a web based application. Block size has been taken as 6. The generated sequence will be concealed with sealed envelope method. Recruitment of participants and the allocation will be done by two different medical officers leading to allocation concealment.

Alfacalcidol 0.25 microgram capsule will be given to the intervention arm once a day orally as Vitamin D supplementation for a period of 4 weeks.

Folic acid 1 mg tablet will be given once a day orally for the control arm as placebo for a period of 4 weeks.

In addition, folic acid 1 mg tablet once day orally will be given to both groups as it is the standard antenatal practice of Sri Lanka (The control arm will receive this folic acid treatment on top of the placebo treatment).

During the trial period blood sugar will be routinely monitored and fetal monitoring will be carried out. If a participant needs to be started on insulin according to blood sugar measurements, they will be dropped from the trial and insulin treatment will be initiated.

Outcomes will be measured only in participants who still remain within inclusion criteria after completion of the trial.

If patients are removed due to adverse effects of Vitamin D it will be specifically reported in the conclusion and will also be reported to the National Medicines Regulatory Authority.

Inclusion criteria

  1. Pregnant women
  2. Aged 18-40 years
  3. Diagnosed as a Gestational diabetes by 75g Oral Glucose tolerance test
  4. On medical nutritional therapy and/or metformin.

Exclusion criteria

  1. Premature pre-labour rupture of membrane
  2. Existing liver or kidney disease
  3. Placental abruption
  4. Pregnancy induced hypertension or Pre eclampsia
  5. Diagnosed with Type 2 diabetes mellitus
  6. Need insulin therapy during the intervention or already on insulin therapy
  7. Smoking
  8. Diagnosed with hypothyroidism
  9. Diagnosed with calcium or vitamin D metabolism disorders
  10. Already on Vitamin D supplementation

Primary outcome(s)


The mean difference of blood glucose levels in the two arms before and after the intervention.

Blood glucose levels will be measured by fasting blood sugar (FBS) test and 1hour post prandial blood sugar (PPBS) (post breakfast) test


Day1 (before the intervention) and after 4 weeks of intervention.


Secondary outcome(s)

  1. Occurrence of adverse drug effects such as craniofacial abnormalities, and dental abnormalities in infants.
  2. Any other allergic reactions to the vitamin D treatment.
  3. Side effects to participant due to excessive vitamin D intake such as,
    • Kidney stones
    • Confusion or disorientation
    • Muscle weakness
    • Bone pain
    • Poor appetite
    • Extreme thirst
    • Nausea, vomiting, or constipation.

  4. Reduction in incidence of the following within the first 24 hours from delivery
  5. Admissions to Premature Babies Unit (PBU) after delivery
  6. Macrosomia
  7. Polyhydramnios
  8. Shoulder dystocia
  9. Neonatal hypoglycemia

Any difference of occurrence of the following
10. Gestational hypertension during the pregnancy
11. Caesarian section rate
12. Instrumental delivery rates

  1. Adverse effects to Vitamin D in participant will be monitored during the trial period and until the delivery.

  2. Occurrence of mentioned adverse drug effects in neonate will be observed within the first 24 hours of the delivery.


Target number/sample size

48 (24 in each arm)

Countries of recruitment

Sri Lanka

Anticipated start date


Anticipated end date


Date of first enrollment

Date of study completion

Recruitment status


Funding source

None (Investigator funded)

Regulatory approvals

State of Ethics Review Approval



Date of Approval


Approval number


Details of Ethics Review Committee

Name: 5. Ethics Review Committee, Faculty of Medicine, University of Kelaniya
Institutional Address:PO Box 6, Thalagolla Road, Ragama Sri Lanka
Email: erckelaniya@gmail.com

Contact & Sponsor Information

Contact person for Scientific Queries/Principal Investigator

Dr. Tharaka Sandaruwan
Colombo North Teaching Hospital, Ragama



Contact Person for Public Queries

Dr. Carmeline Motha
Consultant Physician
Ward 24/25 Colombo North Teaching Hospital, Ragama



Primary study sponsor/organization

Colombo North Teaching Hospital

Hospital Inner Road, Ragama 11010
Tel: 0112960023 0112960523


Secondary study sponsor (If any)


Trial Completion details

Do the investigators plan to share identified individual clinical trial participant-level data (IPD)?

IPD sharing plan description

Not available

Study protocol available

Protocol version and date

Not Available

Protocol URL

Not Available

Results summary available


Date of posting results

Date of study completion

Final sample size

Date of first publication

Link to results

Brief summary of results