Maternal obesity and excessive gestational weight gain may have persistent effects on offspring fat development. However, it remains unclear whether these effects differ by severity of obesity, and whether these effects are restricted to the extremes of maternal body mass index (BMI) and gestational weight gain. We aimed to assess the separate and combined associations of maternal BMI and gestational weight gain with the risk of overweight/obesity throughout childhood, and their population impact. We conducted an individual participant data meta-analysis of data from 162,129 mothers and their children from 37 pregnancy and birth cohort studies from Europe, North America, and Australia. We assessed the individual and combined associations of maternal pre-pregnancy BMI and gestational weight gain, both in clinical categories and across their full ranges, with the risks of overweight/obesity in early (2.0–5.0 years), mid (5.0–10.0 years) and late childhood (10.0–18.0 years), using multilevel binary logistic regression models with a random intercept at cohort level adjusted for maternal sociodemographic and lifestyle-related characteristics. We observed that higher maternal pre-pregnancy BMI and gestational weight gain both in clinical categories and across their full ranges were associated with higher risks of childhood overweight/obesity, with the strongest effects in late childhood (odds ratios [ORs] for overweight/obesity in early, mid, and late childhood, respectively: OR 1.66 [95% CI: 1.56, 1.78], OR 1.91 [95% CI: 1.85, 1.98], and OR 2.28 [95% CI: 2.08, 2.50] for maternal overweight; OR 2.43 [95% CI: 2.24, 2.64], OR 3.12 [95% CI: 2.98, 3.27], and OR 4.47 [95% CI: 3.99, 5.23] for maternal obesity; and OR 1.39 [95% CI: 1.30, 1.49], OR 1.55 [95% CI: 1.49, 1.60], and OR 1.72 [95% CI: 1.56, 1.91] for excessive gestational weight gain). The proportions of childhood overweight/obesity prevalence attributable to maternal overweight, maternal obesity, and excessive gestational weight gain ranged from 10.2% to 21.6%. Relative to the effect of maternal BMI, excessive gestational weight gain only slightly increased the risk of childhood overweight/obesity within each clinical BMI category (p-values for interactions of maternal BMI with gestational weight gain: p = 0.038, p < 0.001, and p = 0.637 in early, mid, and late childhood, respectively). Limitations of this study include the self-report of maternal BMI and gestational weight gain for some of the cohorts, and the potential of residual confounding. Also, as this study only included participants from Europe, North America, and Australia, results need to be interpreted with caution with respect to other populations. In this study, higher maternal pre-pregnancy BMI and gestational weight gain were associated with an increased risk of childhood overweight/obesity, with the strongest effects at later ages. The additional effect of gestational weight gain in women who are overweight or obese before pregnancy is small. Given the large population impact, future intervention trials aiming to reduce the prevalence of childhood overweight and obesity should focus on maternal weight status before pregnancy, in addition to weight gain during pregnancy.

Background: A considerable body of evidence accumulated especially during the last decade, demonstrating that early nutrition and lifestyle have long-term effects on later health and disease (“developmental or metabolic programming”). Methods: Researchers involved in the European Union funded international EarlyNutrition research project consolidated the scientific evidence base and existing recommendations to formulate consensus recommendations on nutrition and lifestyle before and during pregnancy, during infancy and early childhood that take long-term health impact into account. Systematic reviews were performed on published dietary guidelines, standards and recommendations, with special attention to long-term health consequences. In addition, systematic reviews of published systematic reviews on nutritional interventions or exposures in pregnancy and in infants and young children aged up to 3 years that describe effects on subsequent overweight, obesity and body composition were performed. Experts developed consensus recommendations incorporating the wide-ranging expertise from additional 33 stakeholders. Findings: Most current recommendations for pregnant women, particularly obese women, and for young children do not take long-term health consequences of early nutrition into account, although the available evidence for relevant consequences of lifestyle, diet and growth patterns in early life on later health and disease risk is strong. Interpretation: We present updated recommendations for optimized nutrition before and during pregnancy, during lactation, infancy and toddlerhood, with special reference to later health outcomes. These recommendations are developed for affluent populations, such as women and children in Europe, and should contribute to the primary prevention of obesity and associated non-communicable diseases.

Gestational diabetes and gestational hypertensive disorders are associated with offspring obesity, but the role of maternal adiposity in these associations remains unclear. We aimed to investigate whether these pregnancy complications affect the odds of offspring obesity independently of maternal obesity. We did an individual participant data (IPD) meta-analysis of mother-offspring pairs from prospective birth cohort studies that had IPD on mothers with singleton liveborn children born from 1989 onwards and had information available about maternal gestational diabetes, gestational hypertension or pre-eclampsia, and childhood body-mass index (BMI). We applied multilevel mixed-effects models to assess associations of gestational diabetes, gestational hypertension, and pre-eclampsia with BMI SD scores and the odds of overweight and obesity throughout childhood, adjusting for lifestyle characteristics (offspring's sex, maternal age, educational level, ethnicity, parity, and smoking during pregnancy). We then explored the extent to which any association was explained by maternal pre-pregnancy or early-pregnancy BMI. 160 757 mother-offspring pairs from 34 European or North American cohorts were analysed. Compared with uncomplicated pregnancies, gestational diabetes was associated with increased odds of overweight or obesity throughout childhood (odds ratio [OR] 1·59 [95% CI 1·36 to 1·86] for early childhood [age 2·0-4·9 years], 1·41 [1·26 to 1·57] for mid childhood [5·0-9·9 years], and 1·32 [0·97 to 1·78] for late childhood [10·0-17·9 years]); however, these associations attenuated towards the null following adjustment for maternal BMI (OR 1·35 [95% CI 1·15 to 1·58] for early childhood, 1·12 [1·00 to 1·25] for mid childhood, and 0·96 [0·71 to 1·31] for late childhood). Likewise, gestational hypertension was associated with increased odds of overweight throughout childhood (OR 1·19 [95% CI 1·01 to 1·39] for early childhood, 1·23 [1·15 to 1·32] for mid childhood, and 1·49 [1·30 to 1·70] for late childhood), but additional adjustment for maternal BMI largely explained these associations (1·01 [95% CI 0·86 to 1·19] for early childhood, 1·02 [0·95 to 1·10] for mid childhood, and 1·18 [1·03 to 1·36] for late childhood). Pre-eclampsia was associated with decreased BMI in early childhood only (difference in BMI SD score -0·05 SD score [95% CI -0·09 to -0·01]), and this association strengthened following additional adjustment for maternal BMI. Although lowering maternal risk of gestational diabetes, gestational hypertension, and pre-eclampsia is important in relation to maternal and fetal pregnancy outcomes, such interventions are unlikely to have a direct impact on childhood obesity. Preventive strategies for reducing childhood obesity should focus on maternal BMI rather than on pregnancy complications. EU's Horizon 2020 research and innovation programme (LifeCycle Project).

Background/Aims: It has been hypothesized that the intrauterine environment is an independent factor in obesity development. If so, the maternal effect is likely to be a stronger influencing factor (‘fetal overnutrition hypothesis'). We aimed to systematically evaluate the associations of offspring body mass index (BMI, or adiposity) with pre-pregnancy BMI (or adiposity) of the mother and the father. Methods: The Medline, Embase and Cochrane Library databases were searched in March 2012. Results: Seven cohort studies were eligible for the analysis. Among these, 2 groups of trials presented different data from the same parent-offspring cohorts (the Avon Longitudinal Study of Parents and Children, ALSPAC, and the Mater-University Study of Pregnancy, MUSP). In total, 3 large birth cohorts and 1 additional small study were identified. Three studies provided a direct comparison of parent-offspring associations, with a statistically stronger maternal influence found only in the MUSP cohort. Equivocal results were obtained from all studies describing the ALSPAC cohort. The parental effect (indirectly estimated based on the presented odds ratio) was similar in the Finnish cohort. In 1 additional small study, maternal BMI was found to be a strong predictor of childhood obesity. Conclusions: There is only limited evidence to support the ‘fetal overnutrition hypothesis'.