Lactation intensity and postpartum maternal glucose tolerance and insulin resistance in women with recent GDM: the SWIFT cohort.
OBJECTIVE
To examine the association between breastfeeding intensity in relation to maternal blood glucose and insulin and glucose intolerance based on the postpartum 2-h 75-g oral glucose tolerance test (OGTT) results at 6-9 weeks after a pregnancy with gestational diabetes mellitus (GDM).


METHODS
We selected 522 participants enrolled into the Study of Women, Infant Feeding, and Type 2 Diabetes (SWIFT), a prospective observational cohort study of Kaiser Permanente Northern California members diagnosed with GDM using the 3-h 100-g OGTT by the Carpenter and Coustan criteria. Women were classified as normal, prediabetes, or diabetes according to American Diabetes Association criteria based on the postpartum 2-h 75-g OGTT results.


RESULTS
Compared with exclusive or mostly formula feeding (>17 oz formula per 24 h), exclusive breastfeeding and mostly breastfeeding (≤6 oz formula per 24 h) groups, respectively, had lower adjusted mean (95% CI) group differences in fasting plasma glucose (mg/dL) of -4.3 (-7.4 to -1.3) and -5.0 (-8.5 to -1.4), in fasting insulin (μU/mL) of -6.3 (-10.1 to -2.4) and -7.5 (-11.9 to -3.0), and in 2-h insulin of -21.4 (-41.0 to -1.7) and -36.5 (-59.3 to -13.7) (all P < 0.05). Exclusive or mostly breastfeeding groups had lower prevalence of diabetes or prediabetes (P = 0.02).


CONCLUSIONS
Higher intensity of lactation was associated with improved fasting glucose and lower insulin levels at 6-9 weeks' postpartum. Lactation may have favorable effects on glucose metabolism and insulin sensitivity that may reduce diabetes risk after GDM pregnancy.
Division of Research, Kaiser Permanente Northern California, Oakland, California, USA. Erica.Gunderson@kp.org
Erica P
EP
Gunderson
Monique M
MM
Hedderson
Vicky
V
Chiang
Yvonne
Y
Crites
David
D
Walton
Robert A
RA
Azevedo
Gary
G
Fox
Cathie
C
Elmasian
Stephen
S
Young
Nora
N
Salvador
Michael
M
Lum
Charles P
CP
Quesenberry
Joan C
JC
Lo
Barbara
B
Sternfeld
Assiamira
A
Ferrara
Joseph V
JV
Selby
D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D001903:Bottle Feeding / Q000706:statistics & numerical data; D001942:Breast Feeding / Q000706:statistics & numerical data*; D002140:California / Q000453:epidemiology; D015331:Cohort Studies; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology; D016640:Diabetes, Gestational / Q000503:physiopathology*; D005260:Female; D018149:Glucose Intolerance / Q000453:epidemiology*; D005951:Glucose Tolerance Test; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007328:Insulin / Q000097:blood / Q000502:physiology; D007333:Insulin Resistance / Q000502:physiology*; D007774:Lactation / Q000502:physiology*; D008875:Middle Aged; D011247:Pregnancy; D015995:Prevalence; D011446:Prospective Studies
D001786:Blood Glucose; D007328:Insulin