SWIFT: Study of Women, Infant Feeding and Type 2 Diabetes After GDM Pregnancy (SWIFT)

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT01967030
Recruitment Status : Active, not recruiting
First Posted : October 22, 2013
Last Update Posted : July 31, 2017
Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)
Information provided by (Responsible Party):
Kaiser Permanente

Brief Summary:
The goal of the Study of Women, Infant Feeding and Type 2 Diabetes after GDM pregnancy (SWIFT) is to determine whether exposure to prolonged, intensive lactation, as compared to formula feeding, reduces the 2-year incidence of type 2 diabetes mellitus among 1,035 women with a recent GDM pregnancy. The study will also examine whether lactation intensity and duration have persistent favorable effects on blood glucose, insulin resistance, weight gain, change in waist circumference, and adiposity during the two-year postpartum period. SWIFT is a prospective, longitudinal observational study in women at high risk for conversion to diabetes and prediabetes during midlife.

Condition or disease
Type 2 Diabetes

Detailed Description:
SWIFT is a prospective, observational, longitudinal cohort study of 1,035 women diagnosed with GDM during pregnancy who delivered a singleton, live born infant of at least 35 weeks gestation at a Kaiser Permanente Northern California hospital from 2008 to 2011, and were enrolled into the study within 6-9 weeks postpartum. The SWIFT cohort is racially and ethnically diverse with 35% Asian, 9% Black, 31% Hispanic, 23% White, and 2% other race groups. Study enrollment began in mid 2008 and was completed in December 2011, although annual follow up exams will continue through December 2013. Women enrolled into the study met eligibility criteria, and provided written, informed consent for all study procedures prior to the assessments at the in-person exam at 6-9 weeks postpartum (study baseline). Participants were screened for type 2 diabetes at enrollment and thereafter at annual exams during the subsequent two years using the 2-hour 75 gram Oral Glucose Tolerance Test (OGTT). The primary outcome is progression to glucose intolerance, defined as incident diabetes by ADA criteria within 2 years post-delivery based on the 2-hour 75 gram OGTT results at one year and two years postpartum. The primary exposure is lactation intensity and duration assessed from in-patient hospital delivery records, at annual postpartum in-person exams, telephone calls at 1 month postpartum, and via self-administered monthly mailed surveys (from 3 to 11 months postpartum). Data collection after GDM diagnosis started in late gestation throughout the two-year postpartum period, and it was accomplished via electronic medical records for perinatal course (e.g., GDM severity and treatment, gestational weight gain) and for maternal and newborn outcomes, telephone contacts, mailed infant feeding diaries and surveys, self- and interviewer-administered questionaires at in-person exams. Maternal characteristics assessed for this study included breastfeeding intensity and duration, infant feeding practices, sociodemographics, medical and reproductive history, medication use, recurrence of GDM, lifestyle behaviors, depression, and sleep habits. SWIFT also collected these data prospectively via monthly mailings and during annual in-person exams. In addition, trained research assistants measured anthropometry and body composition via bioelectrical impedance according to standardized protocols, processed and stored biospecimens, and collected other data via self- and interviewer-administered questionnaires at each in-person exam.

Study Type : Observational
Actual Enrollment : 1035 participants
Observational Model: Cohort
Time Perspective: Prospective
Official Title: SWIFT: Study of Women, Infant Feeding and Type 2 Diabetes After GDM Pregnancy
Study Start Date : May 2008
Estimated Primary Completion Date : June 2020
Estimated Study Completion Date : June 2020

Resource links provided by the National Library of Medicine

Women with recent GDM pregnancy
The study cohort includes women who had gestational diabetes mellitus (GDM) in their index pregnancy for study enrollment. There are two pre-defined groups: 1) women who breastfeed intensively during the first 4 months postpartum, and 2) women who mostly fed formula during the first 4 months postpartum. The study enrolled women into these pre-defined groups, but some women transitioned into mixed feeding groups after enrollment.

Primary Outcome Measures :
  1. Incident Type 2 Diabetes [ Time Frame: 2 years postpartum ]
    Two-hour 75 gram oral glucose tolerance test; fasting plasma and 2-hour post-load plasma samples analyzed for glucose and insulin concentrations.

Secondary Outcome Measures :
  1. Maternal weight [ Time Frame: 2 years postpartum ]
    Body weight

  2. Body composition [ Time Frame: 2 years postpartum ]
    Tetra polar Bioelectrical impedance to estimate percent body fat

  3. Maternal waist circumference [ Time Frame: 2 years postpartum ]
    Waist circumference

Other Outcome Measures:
  1. Insulin Resistance Index [ Time Frame: 2 years postpartum ]
    Fasting plasma and 2 hour post-load plasma assayed for concentrations of glucose and insulin. These measures will be used to calculate homeostatic model assessment of insulin resistance (HOMA-IR).

  2. Insulin secretion Index [ Time Frame: 2 years postpartum ]
    Fasting plasma and 2 hour post-load plasma assayed for concentrations of glucose and insulin. These measures will be used to calculate the homeostatic model assessment of insulin secretion (HOMA-ß).

Biospecimen Retention:   Samples With DNA
We collected fasting and 2-hour plasma specimens during each Oral Glucose Tolerance Test (OGTT). The EDTA treated plasma specimens and buffy coats are stored in cryovials at -70 degrees Centrigrade in low temperature freezers.

Information from the National Library of Medicine

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Ages Eligible for Study:   20 Years to 45 Years   (Adult)
Sexes Eligible for Study:   Female
Accepts Healthy Volunteers:   No
Sampling Method:   Non-Probability Sample
Study Population

SWIFT participants were recruited from 13 Kaiser Permanente Northern California (KPNC) medical facilities throughout the region. Participating field sites for data collection were located within the three primary areas including:

North area: Sacramento, South Sacramento, and Roseville Medical Centers, and Rancho Cordova, Elk Grove, Point West, and Folsom Medical Offices; East area: Division of Research (DOR) Research Clinic (Oakland), Hayward Medical Center and Fremont Medical Offices and Richmond Medical Center; South area: Santa Clara, and San Jose Medical Centers. The prospective cohort enrolled women who received prenatal care and delivered a singleton, live born infant of 35 weeks gestation or longer at a Kaiser Permanente hospital between July 2008 and October 2011.


Inclusion Criteria:

  • age 20 to 45 years at delivery
  • received prenatal care in Kaiser Permanente Northern California (KPNC) health care system
  • GDM pregnancy diagnosed using the 3-hour 100 g OGTT by Carpenter and Coustan criteria
  • delivered a singleton, live birth >= 35 weeks gestation
  • no pre-existing diabetes or other serious medical conditions prior to index GDM pregnancy
  • no diabetes diagnosis (2-hour 75 gram OGTT) at 6 to 9 weeks postpartum for the index GDM pregnancy
  • no use of thyroid medications, steroids, or other medications affecting glucose tolerance
  • not planning to move from the northern California area within the subsequent 24 months
  • not planning another pregnancy within the next two years
  • Two infant feeding groups: women who did not lactate or did so for less than 3 weeks, OR women who provided no supplemental milk feeds at 2-4 weeks and planned to continue intensive lactation defined as <= 1 formula supplement (6 oz/day) from 6-9 weeks until 4 months or more postpartum.

Exclusion criteria:

  • women who fed breast milk and 7-16 oz of formula (mixed feeding) during the first 4 weeks of life

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT01967030

United States, California
Kaiser Permanente Northern California, Division of Research
Oakland, California, United States, 94612
Sponsors and Collaborators
Kaiser Permanente
Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)
Principal Investigator: Erica P Gunderson, PhD Kaiser Permanente Northern California

Additional Information:
Publications of Results:

Publications automatically indexed to this study by Identifier (NCT Number):
Responsible Party: Kaiser Permanente Identifier: NCT01967030     History of Changes
Other Study ID Numbers: CN-04EGund-03-H
R01HD050625 ( U.S. NIH Grant/Contract )
First Posted: October 22, 2013    Key Record Dates
Last Update Posted: July 31, 2017
Last Verified: July 2017

Keywords provided by Kaiser Permanente:
gestational diabetes mellitus

Additional relevant MeSH terms:
Diabetes Mellitus
Diabetes Mellitus, Type 2
Glucose Metabolism Disorders
Metabolic Diseases
Endocrine System Diseases