Pregnancy as a tissue culture experience: the critical implications of maternal metabolism for fetal development

Maternal overweight is not an independent risk factor for increased birth weight, leptin and insulin in newborns of gestational diabetic women: observations from the prospective 'EaCH' cohort study

BACKGROUND

Both gestational diabetes mellitus (GDM) as well as overweight/obesity during pregnancy are risk factors for detrimental anthropometric and hormonal neonatal outcomes, identified to 'program' adverse health predispositions later on. While overweight/obesity are major determinants of GDM, independent effects on critical birth outcomes remain unclear. Thus, the aim of the present study was to evaluate, in women with GDM, the relative/independent impact of overweight/obesity vs. altered glucose metabolism on newborn parameters.

METHODS

The prospective observational 'Early CHARITÉ (EaCH)' cohort study primarily focuses on early developmental origins of unfavorable health outcomes through pre- and/or early postnatal exposure to a 'diabetogenic/adipogenic' environment. It includes 205 mother-child dyads, recruited between 2007 and 2010, from women with treated GDM and delivery at the Clinic of Obstetrics, Charité - Universitätsmedizin Berlin, Germany. Recruitment, therapy, metabolite/hormone analyses, and data evaluation were performed according to standardized guidelines and protocols. This report specifically aimed to identify maternal anthropometric and metabolic determinants of anthropometric and critical hormonal birth outcomes in 'EaCH'.

RESULTS

Group comparisons, Spearman's correlations and unadjusted linear regression analyses initially confirmed that increased maternal prepregnancy body-mass-index (BMI) is a significant factor for elevated birth weight, cord-blood insulin and leptin (all P < 0.05). However, consideration of and adjustment for maternal glucose during late pregnancy showed that no maternal anthropometric parameter (weight, BMI, gestational weight gain) remained significant (all n.s.). In contrast, even after adjustment for maternal anthropometrics, third trimester glucose values (fasting and postprandial glucose at 32nd and 36th weeks' gestation, HbA1c in 3rd trimester and at delivery), were clearly positively associated with critical birth outcomes (all P < 0.05).

CONCLUSIONS

Neither overweight/obesity nor gestational weight gain appear to be independent determinants of increased birth weight, insulin and leptin. Rather, 3rd trimester glycemia seems to be crucial for respective neonatal outcomes. Thus, gestational care and future research studies should greatly consider late pregnancy glucose in overweight/obese women with or without GDM, for evaluation of critical causes and interventional strategies against 'perinatal programming of diabesity' in the offspring.

Physical activity and excess weight in pregnancy have independent and unique effects on delivery and perinatal outcomes

Background

This study examines the effect of low daily physical activity levels and overweight/obesity in pregnancy on delivery and perinatal outcomes.

Methods

A prospective cohort study combining manually collected postnatal notes with anonymised data linkage. A total of 466 women sampled from the Growing Up in Wales: Environments for Healthy Living study. Women completed a questionnaire and were included in the study if they had an available Body mass index (BMI) (collected at 12 weeks gestation from antenatal records) and/or a physical activity score during pregnancy (7-day Actigraph reading). The full statistical model included the following potential confounding factors: maternal age, parity and smoking status. Main outcome measures included induction rates, duration of labour, mode of delivery, infant health and duration of hospital stay.

Findings

Mothers with lower physical activity levels were more likely to have an instrumental delivery (including forceps, ventouse and elective and emergency caesarean) in comparison to mothers with higher activity levels (adjusted OR:1.72(95%CI: 1.05 to 2.9)). Overweight/obese mothers were more likely to require an induction (adjusted OR:1.93 (95%CI 1.14 to 3.26), have a macrosomic baby (adjusted OR:1.96 (95%CI 1.08 to 3.56) and a longer hospital stay after delivery (adjusted OR:2.69 (95%CI 1.11 to 6.47).

Conclusions

The type of delivery was associated with maternal physical activity level and not BMI. Perinatal outcomes (large for gestational age only) were determined by maternal BMI.

The diabetic pregnancy and offspring blood pressure in childhood: a systematic review and meta-analysis

AIMS/HYPOTHESIS

Offspring of diabetic mothers have increased risk of the metabolic syndrome in adulthood. Studies examining BP in offspring of diabetic mothers have conflicting conclusions. We performed a systematic review and meta-analysis of studies reporting offspring BP in children born to diabetic mothers.

METHODS

Citations were identified in PubMed. Authors were contacted for additional data. Systolic and diastolic BP in offspring of diabetic mothers and controls were compared. Subgroup analysis of type of maternal diabetes and offspring sex were performed. Fixed-effects models were used, and random-effects models where significant heterogeneity was present. Meta-regression was used to test the relationship between offspring systolic BP and prepregnancy BMI.

RESULTS

Fifteen studies were included in the review and 13 in the meta-analysis. Systolic BP was higher in offspring of diabetic mothers (mean difference 1.88 mmHg [95% CI 0.47, 3.28]; p = 0.009). Offspring of mothers with gestational diabetes had similar diastolic BP to controls, but higher systolic BP (1.39 mmHg [95% CI 0.00, 2.77]; p = 0.05); results for type 1 diabetes were inconclusive and there were no separate data available on offspring of type 2 diabetic mothers. Male offspring of diabetic mothers had higher systolic BP (2.01 mmHg [95% CI 0.93, 3.10]; p = 0.0003) and diastolic BP (1.12 mmHg [95% CI 0.36, 1.88]; p = 0.004) than controls; in female offspring there was no difference (systolic: 0.54 mmHg [95% CI -1.83, 2.90], p = 0.66; diastolic: 0.51 mmHg [95% CI -1.07, 2.09], p = 0.52). The correlation between offspring systolic BP and maternal prepregnancy BMI was not significant (p = 0.37).

CONCLUSIONS/INTERPRETATION

Offspring of diabetic mothers have higher systolic BP than controls. Differences related to sex and type of maternal diabetes require further investigation.

Birth weight and long-term overweight risk: systematic review and a meta-analysis including 643,902 persons from 66 studies and 26 countries globally

BACKGROUND

Overweight is among the major challenging health risk factors. It has been claimed that birth weight, being a critical indicator of prenatal developmental conditions, is related to long-term overweight risk. In order to check this important assumption of developmental and preventive medicine, we performed a systematic review and comprehensive meta-analysis.

METHODS AND FINDINGS

Relevant studies published up to January 2011 that investigated the relation between birth weight and later risk of overweight were identified through literature searches using MEDLINE and EMBASE. For meta-analysis, 66 studies from 26 countries and five continents were identified to be eligible, including 643,902 persons aged 1 to 75 years. We constructed random-effects and fixed-effects models, performed subgroup-analyses, influence-analyses, assessed heterogeneity and publication bias, performed meta-regression analysis as well as analysis of confounder adjusted data. Meta-regression revealed a linear positive relationship between birth weight and later overweight risk (p<0.001). Low birth weight (<2,500 g) was found to be followed by a decreased risk of overweight (odds ratio (OR) =0.67; 95% confidence interval (CI) 0.59-0.76). High birth weight (>4,000 g) was associated with increased risk of overweight (OR=1.66; 95% CI 1.55-1.77). Results did not change significantly by using normal birth weight (2,500-4,000 g) as reference category (OR=0.73, 95% CI 0.63-0.84, and OR=1.60, 95% CI 1.45-1.77, respectively). Subgroup- and influence-analyses revealed no indication for bias/confounding. Adjusted estimates indicate a doubling of long-term overweight risk in high as compared to normal birth weight subjects (OR=1.96, 95% CI 1.43-2.67).

CONCLUSIONS

Findings demonstrate that low birth weight is followed by a decreased long-term risk of overweight, while high birth weight predisposes for later overweight. Preventing in-utero overnutrition, e.g., by avoiding maternal overnutrition, overweight and/or diabetes during pregnancy, might therefore be a promising strategy of genuine overweight prevention, globally.

Maternal macronutrient and energy intakes in pregnancy and offspring intake at 10 y: exploring parental comparisons and prenatal effects

BACKGROUND

High maternal dietary intakes in pregnancy may lead to increased fetal growth and program neuroendocrine pathways that result in greater appetite, energy intake, and adiposity in offspring later in life. Few prospective dietary studies have explored this relation.

OBJECTIVE

The objective was to assess associations of maternal dietary intake in pregnancy and maternal and paternal dietary intake postnatally with child dietary intake and adiposity.

DESIGN

Dietary intakes of energy, protein, total fat, and carbohydrate were assessed prospectively in mothers during pregnancy, in mothers and their partners at 47 mo postnatally, and in children at 10 y (n = 5717 mother-child pairs prenatally, 5593 mother-child pairs postnatally, and 3009 father-child pairs). Child body composition was assessed at 9 and 11 y (n = 5725).

RESULTS

Maternal dietary intakes of protein, fat (when adjusted for energy intake), and carbohydrate in pregnancy were positively associated with child dietary intakes of the same nutrients, and these associations were greater than those observed for paternal dietary intake, which was not strongly associated with offspring diet. Associations of maternal prenatal-offspring intakes were stronger than those of maternal postnatal-offspring intakes for protein and fat. Greater child energy and macronutrient intakes were only associated with greater adiposity in children when adjusted for potential energy underreporting. Maternal diet during pregnancy was not associated with offspring adiposity or lean mass.

CONCLUSION

The stronger prenatal maternal associations with child dietary intake, particularly protein and fat, compared with both paternal intake associations and maternal postnatal intake associations provide some evidence for in utero programming of offspring appetite by maternal intake during pregnancy.

Perinatal Nutrition and Hormone-Dependent Programming of Food Intake

It is increasingly accepted that alterations of the intrauterine and early postnatal nutritional, metabolic and hormonal environment may predispose individuals to development of diseases in later life. Results from studies of the offspring of diabetic mothers strongly support this hypothesis. It has also been suggested that being light at birth leads to an increased risk of the metabolic syndrome (Syndrome X) in later life (the Barker hypothesis). The pathophysiological mechanisms that underlie this programming are unclear. However, hormones are important environment-dependent organizers of the developing neuroendocrine-immune network, which regulates all the fundamental processes of life. Hormones can act as 'endogenous functional teratogens' when present in non-physiological concentrations, induced by alterations in the intrauterine or neonatal environment during critical periods of perinatal life. Perinatal hyperinsulinism is pathognomic in offspring of diabetic mothers. Early hyperinsulinism also occurs as a result of early postnatal overfeeding. In rats, endogenous hyperinsulinism, as well as peripheral or intrahypothalamic insulin treatment during perinatal development, may lead to 'malprogramming' of the neuroendocrine systems regulating body weight, food intake and metabolism. This results in an increased disposition to become obese and to develop diabetes throughout life. Similar malprogramming may occur due to perinatal hypercortisolism and hyperleptinism. With regard to 'small baby syndrome' and the thrifty phenotype hypothesis, we propose that early postnatal overfeeding of underweight newborns may substantially contribute to their long-term risk of obesity and diabetes. In summary, a complex malprogramming of the central regulation of body weight and metabolism may provide a general aetiopathogenetic concept, explaining perinatally acquired disposition to later disease and, thereby, opening a wide field for primary prevention.

Fuel metabolism in deviant fetal growth in offspring of diabetic women

Fetal growth and development from its very first stages of intrauterine life is significantly influenced by the metabolic environment in which the conceptus develops. Maternal disease states such as gestational diabetes and hypertensive pregnancy, representing maternal conditions involved in extremes of impaired fetal growth (macrosomia versus growth restriction), can serve as excellent examples of the various factors that are involved in intrauterine growth.

Metabolic interactions of diabetes and pregnancy

Many of the embryonic and fetal abnormalities that occur in pregnancies complicated by maternal diabetes are the result of development in a metabolically abnormal environment. Diabetic embryopathy (birth defects and spontaneous abortions) results from maternal metabolic abnormalities during the first 6-7 weeks of gestation. The embryopathy appears to be multifactorial in origin, and the resulting defects remain important causes of morbidity and mortality in diabetic pregnancies. Diabetic fetopathy (predominantly macrosomia and neonatal hypoglycemia) results from fetal overnutrition and hyperinsulinemia during the second and third trimesters. Fetopathy may cause significant morbidity not only in the perinatal period, but also in later life as overweight infants grow up to be overweight children and young adults. Careful regulation of maternal metabolism from the preconceptional period onward can reduce greatly or even eliminate the excess risks that have been incurred by infants of diabetic mothers in the past. Successful management of maternal diabetes requires knowledge of the alterations in intermediary metabolism that normally occur during pregnancy, as discussed in this chapter.