Nadine Farah

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.

Correlation Between Birth Weight and Maternal Body Composition

OBJECTIVE: To estimate which maternal body composition parameters measured using multifrequency segmental bioelectric impedance analysis in the first trimester of pregnancy are predictors of increased birth weight. METHODS: Nondiabetic women were recruited after ultrasonographic confirmation of an ongoing singleton pregnancy in the first trimester. Maternal body composition was measured using bioelectric impedance analysis. Multivariable linear regression analysis was performed to identify the strongest predictors of birth weight, with multiple logistic regression analysis performed to assess predictors of birth weight greater than 4 kg. RESULTS: Data were analyzed for 2,618 women, of whom 49.6% (n=1,075) were primigravid and 16.5% (n=432) were obese based on a body mass index (BMI) of 30 or higher. In univariable analysis, maternal age, BMI, parity, gestational age at delivery, smoking, fat mass, and fat-free mass all correlated significantly with birth weight. In multivariable regression analysis, fat-free mass remained a significant predictor of birth weight (model R2=0.254, standardized &bgr;=0.237; P<.001), but no relationship was found between maternal fat mass and birth weight. After adjustment for confounding variables, women in the highest fat-free mass quartile had an adjusted odds ratio of 3.64 (95% confidence interval 2.34–5.68) for a birth weight more than 4 kg compared with those in the lowest quartile. CONCLUSIONS: Based on direct measurements of body composition, birth weight correlated positively with maternal fat-free mass and not adiposity. These findings suggest that, in nondiabetic women, interventions intended to reduce fat mass during pregnancy may not prevent large-for-gestational-age neonates and revised guidelines for gestational weight gain in obese women may not prevent large-for-gestational-age neonates. LEVEL OF EVIDENCE: III

The risk of caesarean section in obese women analysed by parity.

OBJECTIVE This study looked at the association between caesarean section (CS) and Body Mass Index (BMI) in primigravidas compared with multigravidas. STUDY DESIGN We enrolled women at their convenience, in the first trimester after an ultrasound examination confirmed an ongoing pregnancy. Weight and height were measured digitally and BMI calculated. After delivery, clinical details were again collected from the Hospitals computerised database. RESULTS Of the 2000 women enrolled, there were 50.4% (n=1008) primigravidas and 49.6% (n=992) multigravidas. Of the 2000 8.5% were delivered by elective CS and 13.4% were delivered by emergency CS giving an overall rate of 21.9%. The overall CS rate was 30.1% in obese women compared with 19.2% in the normal BMI category (p<0.001). In primigravidas the increase in CS rate in obese women was due to an increase in emergency CS (p<0.005) and in multigravidas the increase was due to an increase in elective CS (p<0.01). In obese primigravidas 20.6% had an emergency section for fetal distress. In obese multigravidas 17.2% had a repeat elective CS. CONCLUSION The influence of maternal obesity on the increase in CS rates is different in primigravidas compared with multigravidas.

Aortic isthmus Doppler velocimetry: role in assessment of preterm fetal growth restriction

Intrauterine fetal growth restriction (IUGR) is an important pregnancy complication associated with significant adverse clinical outcome, stillbirth, perinatal morbidity and cerebral palsy. To date, no uniformly accepted management protocol of Doppler surveillance that reduces mortality and cognitive morbidity has emerged. Aortic isthmus (AoI) evaluation has been proposed as a potential monitoring tool for IUGR fetuses. In this review, the current knowledge of the relationship between AoI Doppler velocimetry and preterm fetal growth restriction is reviewed. Relevant technical aspects and reproducibility data are reviewed as we discuss AoI Doppler and its place within the existing repertoire of Doppler assessments in placental insufficiency. The AoI is a link between the right and left ventricles which perfuse the lower and upper body, respectively. The clinical use of AoI waveforms for monitoring fetal deterioration in IUGR has been limited, but preliminary work suggests that abnormal AoI impedance indices are an intermediate step between placental insufficiency‐hypoxemia and cardiac decompensation. Further prospective studies correlating AoI indices with arterial and venous Doppler indices and perinatal outcome are required before encorporating this index into clinical practice. Copyright

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.

Correlation between maternal inflammatory markers and fetomaternal adiposity.

Outside pregnancy, both obesity and diabetes mellitus are associated with changes in inflammatory cytokines. Obesity in pregnancy may be complicated by gestational diabetes mellitus (GDM) and/or fetal macrosomia. The objective of this study was to determine the correlation between maternal cytokines and fetomaternal adiposity in the third trimester in women where the important confounding variable GDM had been excluded. Healthy women with a singleton pregnancy and a normal glucose tolerance test at 28 weeks gestation were enrolled at their convenience. Maternal cytokines were measured at 28 and 37 weeks gestation. Maternal adiposity was assessed indirectly by calculating the Body Mass Index (BMI), and directly by bioelectrical impedance analysis. Fetal adiposity was assessed by ultrasound measurement of fetal soft tissue markers and by birthweight at delivery. Of the 71 women studied, the mean maternal age and BMI were 29.1 years and 29.2 kg/m(2) respectively. Of the women studied 32 (45%) were obese. Of the cytokines, only maternal IL-6 and IL-8 correlated with maternal adiposity. Maternal TNF-α, IL-β, IL-6 and IL-8 levels did not correlate with either fetal body adiposity or birthweight. In this well characterised cohort of pregnant non-diabetic women in the third trimester of pregnancy we found that circulating maternal cytokines are associated with maternal adiposity but not with fetal adiposity.

Maternal obesity and gestational weight gain

The aim of the study was to analyse gestational weight gain (GWG) according to body mass index (BMI) category and to explore the relationship between GWG and pregnancy complications. Women were recruited in the 1st trimester. Weight and height were measured and BMI calculated. Weight was measured at 38 weeks’ gestation and GWG calculated. Clinical details were obtained prospectively. Of the 604 women recruited, 45.5% were primigravidas and 25.2% were obese. The overall mean GWG was 11.6 kg (SD 6.0). In obese women, the mean GWG was 10.4 kg (SD 7.5) compared with 12.6 kg (SD 5.7) in the normal BMI category (p < 0.001). Maternal obesity but not increased GWG was associated with an increased risk of induction of labour, caesarean section and pre-eclampsia. It was concluded that obese women were more likely to exceed GWG recommendations, despite lower GWG than non-obese women. Maternal obesity and not GWG increased the risk of pregnancy complications.