Metformin for Preeclampsia Prevention in Pregnant Women With Type 1 Diabetes Mellitus

August 20, 2026 updated by: Maisa N. Feghali, MD
Although major advancements have been made in improving glycemic management in type 1 diabetes mellitus (DM), women entering pregnancy with type 1 DM continue to be at dramatically increased risk for adverse maternal and neonatal outcomes, including hypertensive disorders of pregnancy (HDP). At present, there is a lack of effective preventive interventions for HDP, which are associated with significant maternal and neonatal morbidity and mortality. Clinical and in vitro data have shown promise for metformin in prevention of HDP in non-diabetic women. Metformin has a reassuring fetal safety profile and has been well studied in type 1 DM outside of pregnancy. The hypothesis to be tested in this application is that compared to usual care, daily oral metformin therapy initiated prior to 20 weeks' gestation in women with type 1 DM reduces the frequency of HDP.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

24

Phase

  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Pennsylvania
      • Pittsburgh, Pennsylvania, United States, 15213
        • Magee Womens Hospital of UPMC

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 50 years (Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Pregnant women 18-50 years
  • 12 0/7 and 19 6/7 weeks of gestation
  • Diagnosed with type 1 DM prior to pregnancy.

Exclusion Criteria:

  • Known allergy or adverse reaction to metformin
  • Multiple gestation
  • Abnormal obstetrical ultrasound suspicious for major congenital abnormality, known or suspected fetal aneuploidy
  • Medical comorbidities that increase risk for metformin use: renal insufficiency (creatinine > 1.1 mg/dL), proteinuria (P:C >0.3 or 24-hour urine protein > 300 mg), active liver disease (acute hepatitis, chronic active hepatitis, persistently abnormal liver enzymes 3x above normal), inflammatory bowel disease (Crohn's and Ulcerative colitis), major hematologic disorder (including alloimmune and isoimmune thrombocytopenia).

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
No Intervention: Usual care
Experimental: Metformin
Drug: Metformin
Participants randomized to metformin will receive metformin in addition to standard treatment of diabetes during pregnancy

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Rate of hypertensive disorders of pregnancy
Time Frame: Delivery/End of pregnancy
Delivery/End of pregnancy

Secondary Outcome Measures

Outcome Measure
Time Frame
Home glucose levels throughout pregnancy
Time Frame: Weekly, throughout pregnancy from enrollment to delivery
Weekly, throughout pregnancy from enrollment to delivery
Birthweight
Time Frame: Delivery/End of pregnancy
Delivery/End of pregnancy
Neonatal morbidity
Time Frame: Delivery/End of pregnancy
Delivery/End of pregnancy

Other Outcome Measures

Outcome Measure
Time Frame
Gestational weight gain
Time Frame: At time of prenatal visits, throughout pregnancy from enrollment to delivery
At time of prenatal visits, throughout pregnancy from enrollment to delivery
Umbilical cord c-peptide
Time Frame: Delivery/End of pregnancy
Delivery/End of pregnancy
Umbilical cord glucose
Time Frame: Delivery/End of pregnancy
Delivery/End of pregnancy
Neonatal body composition
Time Frame: Delivery/End of pregnancy
Delivery/End of pregnancy

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Maisa N. Feghali, MD

Investigators

  • Principal Investigator: Maisa N Feghali, MD, University of Pittsburgh

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

July 8, 2019

Primary Completion (Actual)

October 30, 2025

Study Completion (Actual)

May 31, 2026

Study Registration Dates

First Submitted

June 15, 2018

First Submitted That Met QC Criteria

June 26, 2018

First Posted (Actual)

June 27, 2018

Study Record Updates

Last Update Posted (Actual)

August 24, 2026

Last Update Submitted That Met QC Criteria

August 20, 2026

Last Verified

August 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • STUDY19060327

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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