Bernard Stuart

Maternal weight and body composition in the first trimester of pregnancy

Objective. Previous studies on weight gain in pregnancy suggested that maternal weight on average increased by 0.5–2.0 kg in the first trimester of pregnancy. This study examined whether mean maternal weight or body composition changes in the first trimester of pregnancy. Design. Prospective observational study. Population. We studied 1,000 Caucasian women booking for antenatal care in the first trimester of pregnancy. Setting. Large university teaching hospital. Methods. Maternal height and weight were measured digitally in a standardized way and Body Mass Index (BMI) was calculated. Maternal body composition was measured using segmental multifrequency Bioelectrical Impedance Analysis (BIA). Sonographic examination confirmed the gestational age and a normal ongoing singleton pregnancy in all subjects. Main outcome measures. Maternal weight, maternal body composition. Results. The mean BMI was 25.7 kg/m2 and 19.0% of the women were in the obese category (≥30.0 kg/m2). Cross‐sectional analysis by gestational age showed that there was no change in mean maternal weight, BMI, total body water, fat mass, fat‐free mass or bone mass before 14 weeks gestation. Conclusions. Contrary to previous reports, mean maternal weight and mean body composition values remain unchanged in the first trimester of pregnancy. This has implications for guidelines on maternal weight gain during pregnancy. We also recommend that calculation of BMI in pregnancy and gestational weight gain should be based on accurate early pregnancy measurements, and not on self‐reported or prepregnancy measurements.

Body Mass Index (BMI) in women booking for antenatal care: Comparison between selfreported and digital measurements

OBJECTIVE We set out to compare measurement of Body Mass Index (BMI) with selfreporting in women early in pregnancy. STUDY DESIGN We studied 100 women booking for antenatal care in the first trimester with a normal ongoing pregnancy. Selfreported maternal weight and height were recorded and the Body Mass Index was calculated. Afterwards maternal weight and height were digitally measured and actual BMI was calculated. RESULTS If selfreporting is used for BMI classification, we found that 22% of women were classified incorrectly when BMI was measured. 12% of the women who were classified as having a normal selfreported BMI were overweight and 5% classified as overweight were obese. Similar findings have been reported outside pregnancy. CONCLUSIONS These findings have implications for clinical practice, and for research studies exploring the relationship between maternal adiposity and pregnancy complications.

Maternal morbid obesity and obstetric outcomes.

Objective: The purpose of this retrospective cohort study was to review pregnancy outcomes in morbidly obese women who delivered a baby weighing 500 g or more in a large tertiary referral university hospital in Europe. Methods: Morbid obesity was defined as a BMI ≧40.0 kg/m2 (WHO). Only women whose BMI was calculated at their first antenatal visit were included. The obstetric out-comes were obtained from the hospital’s computerised database. Results: The incidence of morbid obesity was 0.6% in 5,824 women. Morbidly obese women were older and were more likely to be multigravidas than women with a normal BMI. The pregnancy was compli-cated by hypertension in 35.8% and diabetes mellitus in 20.0% of women. Obstetric interventions were high, with an induction rate of 42.1% and a caesarean section rate of 45.3%. Conclusions: Our findings show that maternal morbid obesity is associated with an alarmingly high incidence of medical complications and an increased level of obstetric interventions. Consideration should be given to developing specialised antenatal services for morbidly obese women. The results also highlight the need to evaluate the effectiveness of prepregnancy interventions in morbidly obese women.

The measurement of maternal adiposity.

Summary The issue of maternal obesity has become a major public health problem. Internationally, the diagnosis of obesity is based on body mass index (BMI) that is, weight in kg/height in m2. While epidemiological associations have been shown between different BMI categories and adverse clinical outcomes, there is also a growing realisation that BMI has significant limitations. In this review, we assess current methods to measure body fat and, in particular, their application in pregnant women.

Body Mass Index and spontaneous miscarriage

OBJECTIVE We compared the incidence of spontaneous miscarriage in women categorised as obese, based on a Body Mass Index (BMI) >29.9 kg/m(2), with women in other BMI categories. STUDY DESIGN In a prospective observational study conducted in a university teaching hospital, women were enrolled at their convenience in the first trimester after a sonogram confirmed an ongoing singleton pregnancy with fetal heart activity present. Maternal height and weight were measured digitally and BMI calculated. Maternal body composition was measured by advanced bioelectrical impedance analysis. RESULTS In 1200 women, the overall miscarriage rate was 2.8% (n=33). The mean gestational age at enrolment was 9.9 weeks. In the obese category (n=217), the miscarriage rate was 2.3% compared with 3.3% in the overweight category (n=329), and 2.3% in the normal BMI group (n=621). There was no difference in the mean body composition parameters, particularly fat mass parameters, between those women who miscarried and those who did not. CONCLUSIONS In women with sonographic evidence of fetal heart activity in the first trimester, the rate of spontaneous miscarriage is low and is not increased in women with BMI>29.9 kg/m(2) compared to women in the normal BMI category.

Birth Weight and Neonatal Adiposity Prediction Using Fractional Limb Volume Obtained with 3D Ultrasound

Introduction: The objective of this investigation was to study fetal thigh volume throughout gestation and explore its correlation with birth weight and neonatal body composition. This novel technique may improve birth weight prediction and lead to improved detection rates for fetal growth restriction. Materials and Methods: Fractional thigh volume (TVol) using 3D ultrasound, fetal biometry and soft tissue thickness were studied longitudinally in 42 mother-infant pairs. The percentages of neonatal body fat, fat mass and fat-free mass were determined using air displacement plethysmography. Correlation and linear regression analyses were performed. Results: Linear regression analysis showed an association between TVol and birth weight. TVol at 33 weeks was also associated with neonatal fat-free mass. There was no correlation between TVol and neonatal fat mass. Abdominal circumference, estimated fetal weight (EFW) and EFW centile showed consistent correlations with birth weight. Thigh volume demonstrated an additional independent contribution to birth weight prediction when added to the EFW centile from the 38-week scan (p = 0.03). Conclusion: Fractional TVol performed at 33 weeks gestation is correlated with birth weight and neonatal lean body mass. This screening test may highlight those at risk of fetal growth restriction or macrosomia.

Prospective risk of fetal death in uncomplicated monochorionic twins

A retrospective cohort study was carried out in a university teaching hospital to determine the prospective risk of unexpected fetal death in uncomplicated monochorionic diamniotic (MCDA) twin pregnancies after viability. All MCDA twins delivered at or after 24 weeks’ gestation from July 1999 to July 2007 were included. Pregnancies with twin–twin transfusion syndrome, growth restriction, structural abnormalities, or twin reversed arterial perfusion sequence were excluded. Of the 144 MCDA twin pregnancies included in our analysis, the risk of intrauterine death was 4.9%. The prospective risk of unexpected intrauterine death was 1 in 43 after 32 weeks’ gestation and 1 in 37 after 34 weeks’ gestation. Our results demonstrate that despite close surveillance, the unexpected intrauterine death rate in uncomplicated MCDA twin pregnancies is high. This rate seems to increase after 34 weeks’ gestation, suggesting that a policy of elective preterm delivery warrants evaluation.

Longitudinal measurement of fetal thigh soft tissue parameters and its role in the prediction of birth weight

The aim of this study was to profile longitudinal changes in thigh muscle and fat with gestation and to determine whether thigh measurements can improve the prediction of birth weight (BW).

Body Mass Index and Blood Pressure Measurement during Pregnancy

Objective. The accurate measurement of blood pressure requires the use of a large cuff in subjects with a high mid-arm circumference (MAC). This prospective study examined the need for a large cuff during pregnancy and its correlation with maternal obesity. Methods. Maternal body mass index (BMI), fat mass, and MAC were measured. Results. Of 179 women studied, 15.6% were obese. With a BMI of level 1 obesity, 44% needed a large cuff and with a BMI of level 2 obesity 100% needed a large cuff. Conclusion. All women booking for antenatal care should have their MAC measured to avoid the overdiagnosis of pregnancy hypertension.

Influence of maternal glycemia on intrauterine fetal adiposity distribution after a normal oral glucose tolerance test at 28 weeks gestation.

Objective. To examine the relationship between maternal glucose levels and intrauterine fetal adiposity distribution in women with a normal oral glucose tolerance test (OGTT) at 28 weeks gestation. Study Design. We recruited 231 women with a singleton pregnancy. At 28 and 37 weeks gestation, sonographic measurements of fetal body composition were performed. Multiple regression analysis was used to study the influence of different maternal variables on fetal adiposity distribution. Results. Maternal glucose levels correlated with the fetal abdominal subcutaneous tissue measurements (r = 0.2; P = 0.014) and with birth weight (r = 0.1; P = 0.04). Maternal glucose levels did not correlate with the fetal mid-thigh muscle thickness and mid-thigh subcutaneous tissue measurements. Conclusion. We found that in nondiabetic women maternal glucose levels not only influence fetal adiposity and birth weight, but also influence the distribution of fetal adiposity. This supports previous evidence that maternal glycemia is a key determinant of intrauterine fetal programming.