Nanna Voldner

Impact of ethnicity on gestational diabetes identified with the WHO and the modified International Association of Diabetes and Pregnancy Study Groups criteria: a population-based cohort study

Objective The International Association of Diabetes and Pregnancy Study Groups (IADPSG) recently proposed new criteria for diagnosing gestational diabetes mellitus (GDM). We compared prevalence rates, risk factors, and the effect of ethnicity using the World Health Organization (WHO) and modified IADPSG criteria. Methods This was a population-based cohort study of 823 (74% of eligible) healthy pregnant women, of whom 59% were from ethnic minorities. Universal screening was performed at 28±2 weeks of gestation with the 75 g oral glucose tolerance test (OGTT). Venous plasma glucose (PG) was measured on site. GDM was diagnosed as per the definition of WHO criteria as fasting PG (FPG) ≥7.0 or 2-h PG ≥7.8 mmol/l; and as per the modified IADPSG criteria as FPG ≥5.1 or 2-h PG ≥8.5 mmol/l. Results OGTT was performed in 759 women. Crude GDM prevalence was 13.0% with WHO (Western Europeans 11%, ethnic minorities 15%, P=0.14) and 31.5% with modified IADPSG criteria (Western Europeans 24%, ethnic minorities 37%, P< 0.001). Using the WHO criteria, ethnic minority origin was an independent predictor (South Asians, odds ratio (OR) 2.24 (95% confidence interval (CI) 1.26–3.97); Middle Easterners, OR 2.13 (1.12–4.08)) after adjustments for age, parity, and prepregnant body mass index (BMI). This increased OR was unapparent after further adjustments for body height (proxy for early life socioeconomic status), education and family history of diabetes. Using the modified IADPSG criteria, prepregnant BMI (1.09 (1.05–1.13)) and ethnic minority origin (South Asians, 2.54 (1.56–4.13)) were independent predictors, while education, body height and family history had little impact. Conclusion GDM prevalence was overall 2.4-times higher with the modified IADPSG criteria compared with the WHO criteria. The new criteria identified many subjects with a relatively mild increase in FPG, strongly associated with South Asian origin and prepregnant overweight.

Physical activity level and weight gain in a cohort of pregnant Norwegian women

Background. It is generally recommended that healthy, pregnant women should engage in moderate exercise on most days of the week. However, there is scant knowledge about the overall physical activity and exercise levels among pregnant women. Purpose. To assess the total physical activity level of pregnant women, and to investigate the association between weight gain, physical activity and exercise during pregnancy. Methods. Pregnant women (n = 467) answered a questionnaire on total physical activity level in gestation week 36. Results. Some 55% of the participants reported working in a sitting position. Most women drove (52.9%) or used public transport (31.7%) to work. A total of 39% reported sedentary activities of ≥4 h (watching television and reading) daily; 19% were defined as non‐exercisers before pregnancy, 30% in the first trimester, 36% in the second trimester and 53% in the third trimester. Fifty women (10.6%) continued to exercise ≥4 times/week in the third trimester. Mean weight gain was 13.8 kg (SD: 5.2). Of the normal pregestational weight women (pre‐BMI: <26) and overweight women (pre‐BMI: ≥26), 32 and 51% had exceeded weight gain above accepted recommendations, respectively. Women who exercised regularly had significantly lower weight gain than inactive women in the third trimester only. Conclusion. Pregnant women have a low total physical activity level, and a high percentage of women exceed the recommended weight gain during pregnancy.

Modifiable determinants of fetal macrosomia: role of lifestyle-related factors

Background. Newborn macrosomia is associated with both short‐ and long‐term health risks for the infant, and increases the prevalence of birth complications. Parity, maternal age and gender of the child are known variables that influence fetal growth. The purpose of the present investigation was to evaluate prospectively the contributions of modifiable maternal predictors of fetal macrosomia (≥4,200 g), which included lifestyle‐related factors, such as nutritional intake, physical activity, and plasma glucose values, in addition to overweight and pregnancy weight gain. Methods. Some 553 women were followed through pregnancy. Predictive variables were subjected to univariate and multiple logistic regression analysis. Among these were: body mass index (BMI), weight gain, maternal subcutaneous fat (mm), fasting and 2‐h plasma glucose, self‐reported physical activity before and during pregnancy, and nutritional intake of macronutrients. Gestational age, parity and gender were also included in the model. All continuous variables were dichotomized using the upper quartile as the cut‐off point in most cases. Results. If physical activity was left out of the analyses, BMI, weight gain, plasma glucose and gestational age were independent determinants of macrosomia. After including low level pre‐gestational physical activity in the model, we found that this was now a significant determinant of delivering a macrosomic infant with an OR = 2.9 (95% CI: 1.9, 7.3). Conclusion. The present study indicates that a low level of pre‐gestational physical activity adds to the modifiable determinants of newborn macrosomia.

Fetal growth versus birthweight: the role of placenta versus other determinants.

Introduction Birthweight is used as an indicator of intrauterine growth, and determinants of birthweight are widely studied. Less is known about determinants of deviating patterns of growth in utero. We aimed to study the effects of maternal characteristics on both birthweight and fetal growth in third trimester and introduce placental weight as a possible determinant of both birthweight and fetal growth in third trimester. Methods The STORK study is a prospective cohort study including 1031 healthy pregnant women of Scandinavian heritage with singleton pregnancies. Maternal determinants (age, parity, body mass index (BMI), gestational weight gain and fasting plasma glucose) of birthweight and fetal growth estimated by biometric ultrasound measures were explored by linear regression models. Two models were fitted, one with only maternal characteristics and one which included placental weight. Results Placental weight was a significant determinant of birthweight. Parity, BMI, weight gain and fasting glucose remained significant when adjusted for placental weight. Introducing placental weight as a covariate reduced the effect estimate of the other variables in the model by 62% for BMI, 40% for weight gain, 33% for glucose and 22% for parity. Determinants of fetal growth were parity, BMI and weight gain, but not fasting glucose. Placental weight was significant as an independent variable. Parity, BMI and weight gain remained significant when adjusted for placental weight. Introducing placental weight reduced the effect of BMI on fetal growth by 23%, weight gain by 14% and parity by 17%. Conclusion In conclusion, we find that placental weight is an important determinant of both birthweight and fetal growth. Our findings indicate that placental weight markedly modifies the effect of maternal determinants of both birthweight and fetal growth. The differential effect of third trimester glucose on birthweight and growth parameters illustrates that birthweight and fetal growth are not identical entities.

Why do pregnant women stop exercising in the third trimester

Current exercise guidelines recommend pregnant women to exercise throughout pregnancy. However, a high percentage of pregnant women are sedentary, and there is an increasing decline of physical activity and exercise, especially in the third trimester. Objective. The aim of the present study was to compare demographic and health‐related factors in pregnant women exercising and not exercising in the third trimester. Design. Cross‐sectional design comparing exercisers and non‐exercisers. Setting. Rikshospitalet University Hospital and Norwegian School of Sport Sciences, Oslo, Norway. Population. Healthy pregnant women (n = 467) were successively allocated from the application form for birth at Rikshospitalet University Hospital. Methods. A questionnaire, including questions about demographic variables, physical activity level, common pregnancy complaints, social modeling, attitudes and barriers towards exercise participation was answered between gestation‐week 32 and 36. Main outcome measures. Demographic variables, pregnancy related health factors and social modeling, including exercise counseling by health care providers, were tested using binary logistic regression analysis. Results. Less than 11% were defined as regular exercisers in the third trimester. Having high gestational weight gain and no social role models with respect to exercise behavior during childhood were inversely associated with third trimester exercise. Pre‐pregnancy exercise was the strongest predictor of regular exercise at late gestation. Not receiving advice about exercise from health professionals was borderline significant. Pelvic girdle pain and sick‐leave were not statistically significant factors. Conclusions. Pre‐pregnancy exercise was strongly related to exercise at late gestation. This study indicates a need for more information and motivation for moderate exercise before and throughout pregnancy.

The STORK Groruddalen research programme: A population-based cohort study of gestational diabetes, physical activity, and obesity in pregnancy in a multiethnic population. Rationale, methods, study population, and participation rates

Background: Gestational diabetes mellitus (GDM) and obesity may cause adverse pregnancy outcomes for mothers and offspring. We have set up a research programme to identify predictors for GDM and fetal growth in a multiethnic population in Oslo to improve the identification of high risk pregnancies and reduce adverse short and long-term outcomes for mothers and offspring. Aims: To present the rationale, methods, study population and participation rates. Methods: Population-based cohort study of pregnant women attending the Child Health Clinics (CHC) in Groruddalen, Oslo, and their offspring. Questionnaire data, blood pressure, anthropometric measurements, and fasting blood and urine samples are collected (gestational weeks 8—20 and 28, and 12 weeks postpartum) and an oral glucose tolerance test (28 weeks). Physical activity is measured, three ultrasound measurements are performed and paternal questionnaire data collected. Routine hospital data are available for all mothers and offspring. Umbilical venous blood and placentas are collected, sampled, and stored and neonatal anthropometric measurements performed. Ethnicity is self-reported country of birth. Results: 823 women were included, 59% of non-Western origin. The participation rate was 74% (64—83% in main ethnic groups), mean age 29.8 years (95% CI 29.5—30.1) and median parity 1 (inter-quartile range 1). The cohort is representative for women attending the CHC with respect to ethnicity and age. A slight selection towards lower parity (South Asians) and age (Africans) was found. Few were lost to follow-up. Conclusions: Unique information is collected from a representative group of multiethnic women to address important public health problems and mechanisms of disease. Participation rates are high in all ethnic groups.

Birth complications, overweight, and physical inactivity

Objective. Maternal lifestyle factors are potential predictors of pregnancy complications. We examined relations between modifiable factors and delivery complications. Design. Prospective cohort. Setting. University hospital antenatal clinic, Oslo, Norway. Sample. A cohort of 553 women followed through pregnancy and delivery. Main outcome measures. Pre‐specified birth complications: cesarean section (CS), operative vaginal deliveries (VDs), third and fourth degree of perineal lacerations and hemorrhage (≥1,000 ml). Methods. Univariate and multiple logistic regression analyses were performed. Besides high birthweight (≥4,200 g), modifiable predictors (high body mass index (BMI), fasting glucose and physical inactivity) and non‐modifiable predictors (parity, maternal age, gestational age, and gender) were considered. Results. Significant predictors for induction of labor were parity (odds ratio (OR): 2.1; 95% CI 1.3–3.5), maternal age (OR: 2.0; 1.2–3.4), gestational age (OR: 1.9; 1.1–3.1), and BMI ≥30 (OR: 4.2; 2.2–7.8, p<0.01). High birthweight and high BMI were overrepresented among CSs. Emergency CS was associated with birthweight (OR: 3.7; 1.7–8.1), parity (OR: 3.5; 1.7–7.2), maternal age (OR: 2.6; 1.3–5.3), and induction of labor (OR: 4.8; 2.6–9.1). After excluding CS, operative VD was associated with parity (OR: 8.7; 3.8–20) and gender (OR: 2.2; 1.2–14.1). Perineal laceration was associated with pre‐gestational physical inactivity (OR: 6.1; 1.6–22.9) and operative VD (OR: 5.1; 1.5–17.6). Hemorrhage was associated with high birthweight (OR: 4.2; 1.2–4.7) and BMI ≥30 (OR: 4.6; 1.2–17.7). Conclusions. Pre‐gestational physical inactivity increased the risk of perineal lacerations and male infants were associated with higher risk of vaginal operative delivery.

Assessing body composition in healthy newborn infants: reliability of dual-energy x-ray absorptiometry.

Dual-energy X-ray absorptiometry (DXA) is used to measure body composition in newborns; however, data on DXA accuracy are limited. We investigated the reliability of body composition measurements by DXA. The present study included 207 normal-term newborn babies, recruited from a larger study on the determinants of birth weight in healthy pregnancies (STORK) between 2005 and 2008. Reliability analysis of total fat mass (FM(DxA)), fat-free mass, lean mass (LM(DxA)), bone mineral content (BMC), and bone mineral density (BMD) were based on 2 DXA scans of 50 neonates. We also performed a comparison analysis for DXA (FM(DxA)) measurements and caliper (CLP) or circumference (CF) measurements of trunk and extremities (performed on all neonates, n=207). Reliability: All intraclass correlation coefficients (ICC) were satisfactory to excellent for total body and the extremity-compartment FM(DxA), LM(DxA), BMD, and BMC; ICC ranged from 0.86 to 0.96 but with a lower ICC for trunk FM(DxA). For comparison analysis, the Pearson correlation coefficients for CLP vs DXA and CF vs DXA ranged from 0.48 to 0.79 and 0.41 to 0.77, respectively. Quadriceps CLP and CF measurements correlated best with the most reliable DXA results, whereas more modest correlations were found for the trunk region. DXA measurements of body composition demonstrated good reliability and can be used as a reference method in neonates. CLP and CF measurements are appropriate for larger cohorts or when DXA is unavailable, and they provide fair rough estimations of fat mass.

Increased risk of macrosomia among overweight women with high gestational rise in fasting glucose

Objectives. Maternal overweight is a risk factor for gestational diabetes (GDM) and for newborn macrosomia. Among women without GDM, it is not well understood why some women with high body mass index (BMI) give birth to macrosomic newborns while others do not. We wanted to explore the effect of BMI and fasting plasma glucose (FPG), fasting plasma insulin (FPI) and insulin resistance (HOMA-IR) on the risk of newborn macrosomia. Methods. A cohort of 553 Caucasian women was followed throughout pregnancy. The dependent variable was high birth weight (≥4200 g). Independent variables included gestational age, intake of macronutrients and energy, maternal BMI, weight gain, FPG, FPI and HOMA-IR. Results. FPG in late pregnancy (30–32 weeks) remained a significant determinant of newborn macrosomia in multiple regression analysis (OR: 1.9, 95% CI: [1.1, 3.4]), whereas FPI and HOMA-IR did not. The women in the highest BMI quartile (≥27 kg/m2) who gave birth to macrosomic newborns had higher increase in FPG and HOMA-IR from early to late pregnancy. Among women in this BMI category, the risk for delivering a macrosomic infant was higher among those with an increase in FPG above 0.60 mmol/l (upper quartile) (OR = 4.5, 95% CI: [1.7, 12.5]). Conclusion. Fasting plasma glucose at week 30–32, but not fasting plasma insulin or insulin resistance, is a determinant of newborn macrosomia. Overweight women with high increase in fasting plasma glucose from early to late pregnancy had a 4.5-fold increase in risk of newborn macrosomia compared to the remaining group with high BMI.

Retinol-binding protein-4 is not strongly associated with insulin sensitivity in normal pregnancies

OBJECTIVE Recently, experimental and clinical studies suggest that retinol-binding protein-4 (RBP4) may provide a link between obesity and insulin resistance. However, no previous studies have investigated the impact of circulating RBP4 on measures of insulin resistance in normal pregnant women, and the objective of this study is to measure serum RBP4 in early and late pregnancy and relate these to measures of insulin resistance and secretion controlling for changes in fat mass. DESIGN AND METHODS Samples were obtained during oral glucose tolerance test (OGTT) from 44 normal pregnancies at weeks 14-16 and 30-32. Measures of fat mass were body mass index (BMI) and leptin while insulin sensitivity and secretion were predicted from OGTT. Leptin and RPB4 were measured by immunoassay. RESULTS Insulin sensitivity decreased during the course of pregnancy. Insulin sensitivity and secretion were best explained by BMI and circulating leptin, but not RBP4, both in early and late pregnancy. However, a marked increase in fasting RBP4 from early to late pregnancy was observed, and this change was associated with a decline in insulin sensitivity. A marked increase in RBP4 was found during OGTT at weeks 14-16 with an opposite temporal course at weeks 30-32. CONCLUSION The increased fat mass and insulin resistance during normal pregnancy was best explained by measures of fat mass. However, the increase in RBP4 from early to late pregnancy, associated with a decline in insulin sensitivity, potentially indicates interactions with glucose metabolism.