Aim: Evaluation of effects of 4-m preconception lifestyle intervention (LSI) on preconception body mass index (BMI),
insulin resistance (IR) and glucose homeostasis and on the frequency and severity of gestational diabetes mellitus (GDM)
during the oncoming pregnancy in women had (Group A)/not (Group B) GDM during previous pregnancy.
Patients and Methods: 498 women; 147 in group A and 351 in group B completed the applied LSI consisted of high-fiber
and low-calorie diet with mild-moderate aerobic exercise for at least 4-m pre-pregnancy. Pre-LSI (T1) and Post-LSI (T2)
evaluations included determination of body mass index (BMI) and determination of variables of glucose homeostasis. Study
outcomes included the effect of the applied LSI on the incidence of newly developed or recurrent IR and of GDM, the success
rate of the applied LSI as defined as the T2-number of new Av women in comparison to their T1-number.
Results: The success rate of the applied LSI was 19.3% and 10.5% among women of groups A and B, respectively for a
total success rate of 12.8%. Mean T2-BMI of all LSI participants was significantly decreased in comparison to their T1-
BMI with significantly higher median value of change in both groups. Moreover, all the glucose homeostasis variables were
significantly reduced. During pregnancy all variables of glucose homeostasis were significantly elevated in comparison to
T2-levels. However, the total incidence of new IR and GDM was significantly (p=0.011 &