Chro Fattah

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.

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.

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.

Miscarriage after Sonographic Confirmation of an Ongoing Pregnancy in Women with Moderate and Severe Obesity

Objective: To compare the incidence of spontaneous miscarriage in women with moderate to severe obesity to that in women with a normal BMI after sonographic confirmation of the foetal heart rate in the first trimester. Methods: Women were enrolled in a prospective observational study at their convenience in the first trimester after an ultrasound confirmed an ongoing singleton pregnancy with foetal heart activity present. Maternal height and weight were measured digitally and BMI was calculated. Results: In the 3,000 women enrolled, the miscarriage rate overall was 3.9% (n = 117). The mean gestational age at enrolment was 11.1 weeks. In the class 2–3 (BMI > 34.9 kg/m2) obese primigravidas the miscarriage rate was 11.3% (n = 8) compared with 2.7% (n = 24) in the normal BMI category (p = 0.003), and 3.7% (n = 5) in the class 1 obese category (not significant). In multigravidas, there was no increased rate of miscarriage among class 2–3 obese women compared with multigravidas in the normal BMI category. The mean body composition values showed that primigravidas who miscarried had both increased fat and fat-free masses compared with those who did not, but multigravidas who miscarried had a similar fat mass and fat-free mass with those who did not. Conclusions: In women with sonographic evidence of foetal heart activity in the first trimester, the rate of spontaneous miscarriage is low. It was increased in moderate to severely obese primigravidas, but was not increased in other obese women compared to women in the normal BMI category.

Are there sex differences in Fetal Abdominal Subcutaneous Tissue (FAST) measurements

OBJECTIVE To determine if Fetal Abdominal Subcutaneous Tissue (FAST) measurements using antenatal ultrasound differ between male and female fetuses. STUDY DESIGN Women who had an ultrasound examination for fetal growth between 20 and 40 weeks gestation were studied. Women with diabetes mellitus were excluded. The fetal anterior abdominal subcutaneous tissue was measured on the anterior abdominal wall in millimetres anterior to the margins of the ribs, using magnification at the level of the abdominal circumference. The fetal sex was recorded after delivery. RESULTS A total of 557 fetuses were measured, 290 male and 267 female. The FAST measurements increased with gestational age. The FAST increased at the same rate for both male and female fetuses and at any given week there was no sex difference. CONCLUSIONS The increased fat composition in females reported after birth was not found in abdominal wall subcutaneous fat measurements using ultrasound during pregnancy. Antenatal centile charts for FAST do not need to be based on sex.