Excess body weight during pregnancy and offspring obesity: Potential mechanisms

Abstract

The rates of child and adult obesity have increased in most developed countries over the past several decades. The health consequences of obesity affect both physical and mental health, and the excess body weight can be linked to an elevated risk for developing type 2 diabetes, cardiovascular problems, and depression. Among the factors that can influence the development of obesity are higher infant weights and increased weight gain, which are associated with higher risk for excess body weight later in life. In turn, mother’s excess body weight during and after pregnancy can be linked to the risk for offspring overweight and obesity through dietary habits, mode of delivery and feeding, breast milk composition, and through the influence on infant gut microbiota. This review considers current knowledge of these potential mechanisms that threaten to create an intergenerational cycle of obesity.

Introduction

Over the past three decades, there has been a substantial increase in the number of individuals who are overweight in the United States [1], and overweight and obesity have become the most prevalent nutritional disorders of children and adolescents. Currently, more than one-third of all children in United States are overweight and more than 15% of children and adolescents are obese, a figure that is nearly triple the rate 2 to 3 decades ago [2], [3]. The health consequences of childhood obesity affect both physical and mental health. Overweight children have an increased incidence of hypertension, coronary artery disease, sleep apnea, orthopedic problems, and type 2 diabetes [1]. The psychological complications include low self-esteem, increased risk for discrimination, and poor body image.

Obesity that begins in childhood tends to be more severe and is associated with greater adverse effects than obesity in adulthood [4]. If a child is overweight by the age of 10 to 13 y, there is a 65% chance he or she will become an overweight adult [5]. Among the factors that can influence the development of childhood obesity, infant weight, and weight gain are significant determinants of future body mass. Infants with excess body weight (EBW) have an increased risk for developing obesity in adolescence and in childhood [6], [7]. For example, the Growing Up Today Study in the United States revealed that each 1 kg increase in infant birth weight was associated with about a 5% increase in the chance of being overweight in adolescence [8]. In turn, infant overweight status can be linked to the weight and obesity of their mothers before, during, and after pregnancy (Fig. 1). Overweight mothers are significantly more likely to have overweight children, and the strongest predictor of child overweight status is the mother’s current EBW [7], [9], [10], [11]. Specifically, a number of studies have reported significantly increased odds ratios (OR) for offspring obesity in obese mothers. These ORs ranged from 3.1 among low income U.S. children in one [12], to 4.3 for U.K children at 7 y of age based on another study [13], to above 5 for U.S. children born between 1980 and 1990 as described in a third study [10]. Among Swedish army conscripts, each unit of maternal body mass index (BMI) increased the OR of recruit obesity by 1.2 [14].

In this review, we consider currently available evidence for potential associations between maternal EBW during and after pregnancy and the risk for offspring developing obesity during childhood or later in life. Because about half of all women of childbearing age in the United States are either overweight or obese [15], and because the rate of obesity in pregnant women also has increased in recent years [16], such a link may create an intergenerational cycle of obesity.