The periconceptional period of mammalian development has been identified as an early ‘developmental window’ during which environmental conditions may influence the pattern of future growth and physiology. Studies in humans and animal models have revealed that factors such as maternal nutritional status or in vitro culture and manipulation of developing gametes and preimplantation embryos can impact upon the long-term health and physiology of the offspring. However, the mechanisms involved in the programming of adult disease in response to altered periconceptional development require increased investigation. The role of epigenetic modifications to DNA and chromatin organisation has been identified as a likely mechanism through which environmental perturbations can affect gene expression patterns resulting in phenotypic change. This study will highlight the sensitivity of two critical stages in early mammalian development, gametogenesis and preimplantation development. We will detail how changes to the immediate environment can not only impact upon developmental processes taking place at that time, but can also affect long-term aspects of offspring health and physiology. We will also discuss the emerging role of epigenetics as a mechanistic link between the environment and the later phenotype of the developing organism.

The fetal insulin hypothesis proposes that low birth weight and susceptibility to type 2 diabetes (T2D) could both be two phenotypes of the same genotype. Insulin is a key growth factor in utero, and T2D is characterized by insulin resistance and/or beta-cell dysfunction. Therefore, genetic variants impacting on insulin secretion and action are likely to alter both fetal growth and susceptibility to T2D. There are three lines of evidence in support of this hypothesis. (1) Studies of rare monogenic diabetes have shown mutations in a single gene, such as GCK or KCNJ11, can cause diabetes by reducing insulin secretion, and these mutations are also associated with reduced birth weight. (2) Epidemiological studies have indicated that children born to fathers with diabetes are born smaller. As the father cannot influence the intrauterine environment, this association is likely to reflect genes inherited by the fetus from the father. (3) The most compelling evidence comes from recent genome-wide association studies. Variants in the CDKAL1 and HHEX-IDE genes that predispose to diabetes, if present in the fetus, are associated with reduced birth weight. These data provide evidence for a genetic contribution to the association between low birth weight and susceptibility to T2D. This genetic background is important to take into consideration when investigating the impact of environmental determinants and developing strategies for intervention and prevention.

Birth weight is emerging as a potentially important risk factor for several chronic diseases with adult onset, including breast cancer. Because participant recall is frequently used to gather data on early life exposures, it is essential that the accuracy of recall be assessed and validated. Self-reported birth weights and birth certificate weights were compared in women aged 35–51 years from the Western New York Exposures and Breast Cancer (WEB) Study, a population-based case–control study. A total of 180 participants had both birth certificate and interview data on birth weight. Participants reported birth weight to one of six categories (<5, 5–5.5, 5.6–7, 7.1–8.5, 8.6–10 and >10 lbs). The Spearman correlation for self-reported and birth certificate weights was 0.67. Sixty percent of participants reported weights with exact agreement with birth certificate; unweighted and weighted kappas (κ) were 0.39 and 0.68, respectively. Spearman correlations were similar for cases (0.67) and controls (0.68). Controls exhibited a significantly higher unweighted κ (0.51) than cases (0.27; P = 0.03), but weighted κ were not statistically different [controls, 0.73; cases, 0.64 (P = 0.32)]. Demographic and anthropometric characteristics were not different between participants who underreported, overreported, or correctly reported their birth weight for either cases or controls. Overall, the level of agreement for report of birth weight and actual birth weight was fair to moderate.

Earlier, we reported that antenatal micronutrient supplementation reduced the risk of metabolic syndrome and microalbuminuria among offspring at 6–8 years of age in rural Nepal. In the same birth cohort, we examined associations of size at birth (weight, length and ponderal index), and gestational age, with cardiometabolic risk factors in childhood across all antenatal micronutrient interventions. There was an inverse association between birth weight and systolic blood pressure (SBP, β = −1.20 mm Hg/kg; 95% confidence interval (CI): −1.93, −0.46) and diastolic blood pressure (DBP, β = −1.24 mm Hg/kg; 95% CI: −2.00, −0.49). Current child body mass index was positively associated with SBP but not with DBP. Birth weight was unassociated with insulin resistance, but each kilogram of increase was associated with a reduced risk of high triglycerides (odds ratio (OR) = 0.64/kg; 95% CI: 0.41, 0.97) and an increased risk of high waist circumference (OR = 3.16/kg; 95% CI: 2.47, 4.41). In this rural Nepalese population of children 6–8 years of age with a high prevalence of undernutrition, size at birth was inversely associated with blood pressure and triglycerides and positively associated with waist circumference.

We hypothesized that the altered placental proportions that influence birth weight affect childhood body proportions, and that these effects would be independent of birth weight. We also hypothesized that altered placental proportions might affect the fetal cardiovascular system, and may be reflected in variation in childhood blood pressure. By using linear regression with birth weight as the dependent variable, placental variables were entered as predictors. The predicted birth weights based on placental factors were then obtained. The ratio of the actual birth weight to that predicted by placental parameters (observed/expected ratio, OER) was used as the independent variable in analyses of age 7 year body mass index (BMI) and diastolic blood pressure (DBP) in the 15,902 singleton liveborns delivered between 34 and 43 weeks. The standardized residual birth weight was also used as a variable to examine the effects of birth weight that is not consistent with placental parameters. For each unit increase in the OER, BMI at 7 years increased 1 kg/m2 (P < 0.0001). The OER also had a significant effect on DBP (β = 4.52, P < 0.001) at 7 years of age but only among African-American children. Results for the standardized residual birth weight variable were consistent with the OER. All results were adjusted for gestational age, sex, socioeconomic status, African-American race and maternal pre-pregnancy BMI. Being larger or smaller than predicted by one’s placenta affects childhood body composition and blood pressure. The placental measurements provide insight into pathophysiological mechanisms of the developmental origins of adult disease.

Little is known about the consequences of maternal copper (Cu) deficiency on the vascular function of offspring or on perpetuation of vascular effects to a second generation. We examined vascular functional responses in mesenteric arteries from Cu-deficient Sprague-Dawley rat dams and from offspring directly exposed to maternal Cu deficiency during development and lactation and perpetuation of the effects in a second generation of offspring. Dams were fed a diet with marginal (1 mg Cu/kg) or adequate (6 mg Cu/kg) Cu for 3 weeks before conception and throughout pregnancy and lactation periods. Half of the first generation (F1) litters were cross-fostered. At reproductive maturity, F1 pairs were bred within groups resulting in second generation (F2) offspring. At 9 weeks of age, mesenteric artery (200 μm) isometric tension was determined in response to vasoconstrictors and vasorelaxants using a small artery wire myograph. Cu deficiency did not alter the vascular function in dams. In F1 offspring, increased responsiveness to potassium chloride in male offspring was due to direct exposure to maternal Cu deficiency in the birth mother, while enhanced endothelium-dependent relaxation responses in female offspring resulted from postnatal exposure to maternal Cu deficiency. Increased endothelium independent and decreased endothelium-dependent relaxation responses were identified in F2 Cu-deficient male offspring. These data indicate that exposure to maternal Cu deficiency during critical windows of development alter the vascular function across two generations of offspring.