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A Comparison Between Two Oral Hypoglycemics - Metformin and Glybenclamide for the Treatment of Gestational Diabetes Mellitus

This study has been completed.
Information provided by (Responsible Party):
HaEmek Medical Center, Israel Identifier:
First received: December 28, 2011
Last updated: September 4, 2016
Last verified: September 2016

Rationale Gestational diabetes mellitus (GDM) complicates 5-7% of pregnancies. Major hazards include macrosomia, polyhydramnios, labor trauma and neonatal hypoglycemia. The ADA and ACOG recommend glucose control in order to reduce the incidence of hyperglycemia induced complications. Glucose control can be achieved using diet and life style changes. Insulin is initiated in women who fail to obtain glucose control with diet alone. During the past 11 years oral hypoglycemic drugs have been tested and proven to be efficacious and safe.


  1. To compare the efficacy and safety of glybenclamide vs. metformin in the treatment of women diagnosed with GDM
  2. To evaluate the improvement in glycemic control after the addition of a second oral hypoglycemic drug after failure of the first

Hypothesis GDM is one of the major conditions contributing to obstetrical complications and prenatal morbidity. Improving glycemic control, by means of improving compliance and patient satisfaction, will decrease obstetrical complications, maternal and neonatal morbidity and have positive long term health implications.

Study design Prospective, randomized, open label

Study population Women between the ages 18-45, diagnosed with GDM will be recruited. GDM will be defined by a pathological OGTT (according to Carpenter and Coustan criteria) performed at or after 13 weeks of gestation.

Study period From recruitment until discharge of the newborn baby after delivery

Power analysis Assuming 80% glycemic control with glybenclamide vs 55% with metformin, 52 women will be needed in each group in order to detect 25% difference in glycemic control rate with α=0.05 and β=0.2.

Study protocol Women will be randomized at recruitment. Demographic and obstetrical data will be collected. Average glucose levels during the previous two weeks, estimated fetal weight and amniotic fluid index, and lab exams reflecting glycemic control will be noted. Women will provide daily glucose levels via fax or mail once a week. Glycemic control will be evaluated by a daily chart, including 7 measurements: 3 preprandial, 3 postprandial and a 7th measurement at 10 pm. Women will be invited to a monthly follow-up, which will include a sonographic evaluation of fetal weight and amniotic fluid, and lab exams. Follow-up protocol after 38 w of gestation will be according to our ward's protocol. The study was approved by the local Helsinki committee.

Time table Duration: two years

Condition Intervention Phase
Gestational Diabetes Mellitus
Drug: metformin
Drug: glybenclamide
Phase 4

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Parallel Assignment
Masking: Open Label
Primary Purpose: Treatment

Resource links provided by NLM:

Further study details as provided by HaEmek Medical Center, Israel:

Primary Outcome Measures:
  • glycemic control [ Time Frame: 2 years ] [ Designated as safety issue: No ]

Enrollment: 108
Study Start Date: January 2012
Study Completion Date: December 2014
Primary Completion Date: June 2014 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Active Comparator: metformin
metformin up to 2550mg per day
Drug: metformin
metformin up to 2550mg per day.
Active Comparator: glybenclamide
glybenclamide up to 20mg per day.
Drug: glybenclamide
glybenclamide up to 20mg per day.


Ages Eligible for Study:   18 Years to 45 Years   (Adult)
Genders Eligible for Study:   Female
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  1. Patients with GDM with a gestational age between 14-33 weeks
  2. Fasting glucose over 95 mg% or over 130 mg% an hour and a half postprandial (PPD) or a daily average over 100 mg%
  3. At least a week of dietary treatment
  4. Sonographic dating of the pregnancy earlier than 24 weeks
  5. Signing a consent form

Exclusion Criteria:

  1. Suspected IUGR earlier than 24 week of gestation
  2. Major fetal malformation
  3. Pre-gestational diabetes mellitus
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT01563120

Dep. OB/GYN, Emek Medical Center
Afula, Israel
Sponsors and Collaborators
HaEmek Medical Center, Israel
  More Information

Responsible Party: HaEmek Medical Center, Israel Identifier: NCT01563120     History of Changes
Other Study ID Numbers: 0002-11-EMC 
Study First Received: December 28, 2011
Last Updated: September 4, 2016
Health Authority: Israel: Ministry of Health

Additional relevant MeSH terms:
Diabetes Mellitus
Diabetes, Gestational
Glucose Metabolism Disorders
Metabolic Diseases
Endocrine System Diseases
Pregnancy Complications
Hypoglycemic Agents
Physiological Effects of Drugs processed this record on October 26, 2016