Objective: to explore relationships between maternal pre-pregnancy weight, third trimester glucose, baby birth weight, weight and metabolic health of the mother and child 5 years after birth.
Design: an observational study set within a non-intervention, longitudinal cohort study looking at insulin resistance in children.
Setting: a teaching hospital in the south west of the United Kingdom.
Participants: 300 mothers and their five-year-old children from randomly selected Plymouth schools, stratified according to socioeconomic status.
Measurements: were obtained from obstetric records maternal pre-pregnant weight, random and fasting third trimester blood glucose, baby birth weight. Five years later the following measurements were made of the mother and child: height, weight, glucose and insulin resistance.
Findings: five years after the pregnancy, 33% of the mothers were overweight, with an additional 19% obese. In the children 13% of boys were overweight (4% obese), and in the girls, 26% were overweight (5% obese). In the five-year-old children, weight (r=0.28, p<0.001) but not birth weight (r=0.03, p=0.573), correlated with insulin resistance. Maternal pre-pregnant weight was related to both random and fasting third trimester glucose, and to insulin resistance 5 years later. Third trimester fasting glucose, even within a normal range, was a better predictor than random glucose of the baby's birth weight (r=0.39, p=0.044) and the mother's future insulin resistance (r=0.67, p<0.001). No maternal measures predicted insulin resistance in the child at 5 years.
Conclusions: maternal weight had an important influence on the gestational environment, and predicted insulin resistance 5 years later. Fasting glucose, even within the reference range, was a better predictor than random glucose of the baby's birth weight and the mother's future insulin resistance.
Implications for practice: these concern the importance of pre-conception weight management, and support replacement of routine random glucose sampling during the third trimester with an earlier, fasting measurement.