Overweight and obesity in pregnancy do not adversely affect neonatal outcomes: new evidence

Association of Maternal Obesity in Early Pregnancy with Adverse Pregnancy Outcomes: A Chinese Prospective Cohort Analysis

OBJECTIVE

This study aimed to examine the associations of maternal obesity in early pregnancy with adverse pregnancy outcomes.

METHODS

A prospective cohort analysis was performed among 18,481 Chinese nulliparous women, using data from a 2006 to 2009 trial of prenatal micronutrient supplementation. Obesity was defined as BMI ≥ 27.5 kg/m² . Interested outcomes included fetal loss (spontaneous abortion plus stillbirth), infant death, total mortality, and preterm and birth weight outcomes.

RESULTS

Compared with normal weight, obesity was associated with total mortality (adjusted relative risks [ARR] 1.34; 95% CI: 1.03-1.74) and fetal loss (ARR 1.51; 95% CI: 1.15-1.99) but not with infant death (ARR 0.53; 95% CI: 0.20-1.46). Further analyses showed that obesity was particularly associated with spontaneous abortion (ARR 1.51; 95% CI: 1.13-2.02) rather than stillbirth (ARR 1.52; 95% CI: 0.65-3.57). Moreover, obesity was associated with preterm birth (ARR 1.59; 95% CI: 1.25-2.02), macrosomia (ARR 3.71, 95% CI: 3.01-4.59), and large for gestational age (ARR 2.93; 95% CI: 2.49-3.47).

CONCLUSIONS

Maternal obesity in early pregnancy is associated with various adverse pregnancy outcomes in Chinese nulliparous women, suggesting the importance of an appropriate weight before and during pregnancy.

Maternal and fetal outcomes in pregnancies complicated by overweight and obesity

BACKGROUND

Overweight and obesity are associated with pregnancy complications and adverse perinatal outcomes, posing short and long-term risks for maternal and child health. This study evaluated maternal, delivery and neonatal outcomes in pregnancies complicated by overweight and obesity.

METHODS

This prospective cross-sectional study included 258 pregnant women. According to prepregnancy body mass index (BMI), participants were classified as normal weight, overweight, or obese. Data were analyzed using the chi-square test and analysis of variance followed by the Tukey test. Logistic regression was performed to calculate odds ratios and 95 % confidence intervals (p < 0.05).

RESULTS

Most women ≥ 35 years old were overweight (22.7 %) and obese (27.6 %). Prepregnancy diabetes was significantly associated with obesity (15.7 %, p < 0.000). Obese women showed the lowest weight gain (9.6 ± 7.5Kg). Overweight and obese women practiced physical exercise more frequently (p = 0.010) than normal weight women. A greater proportion of obese mothers (13.4 %) had large for gestational age babies (p = 0.021), with higher thoracic circumference (33.6 ± 2.0 cm) and abdominal circumference (31.6 ± 2.3 cm). Obesity increased the risk of developing hypertension (OR = 7.0; 3.1-15.9), hyperglycemic disturbances (OR = 5.5; 2.9-10.6) and HbA1c ≥ 6.5 % (OR = 3.7; 1.2-11.1). The infants born to obese mothers had longer hospital stay (3.9 ± 3.9 days) (p = 0.005).

CONCLUSION

Our results confirm that obesity in pregnancy can lead to adverse outcomes, and underscore the importance of identifying and treating inadequate weight status during pregnancy.

The combined effect of maternal obesity and fetal macrosomia on pregnancy outcomes

OBJECTIVE

To examine the combined effect of macrosomia and maternal obesity on adverse pregnancy outcomes using a retrospective cohort.

METHODS

Infants with a birth weight of ≥ 4000g (macrosomia) were identified from an institutional birth cohort. Demographic characteristics and maternal, fetal, neonatal, and pregnancy outcomes of macrosomic infants whose mothers were obese were compared with those whose mothers were non-obese.

RESULTS

Pregnancies in obese women resulting in macrosomic infants are more likely to be complicated by gestational diabetes, gestational hypertension, and smoking than pregnancies in non-obese women with macrosomic infants. Mothers whose infants are macrosomic are significantly more likely to require induction of labour (OR 1.42; 95% CI 1.10 to 1.98) and delivery by Caesarean section (OR 1.45; 95% CI 1.04 to 2.01), particularly for maternal indications (OR 3.7; 95% CI 1.47 to 9.34), if they are obese. Finally, macrosomic infants of obese mothers are significantly more likely to require neonatal resuscitation in the form of free flow oxygen (OR 1.57; 95% CI 1.03 to 2.42) than macrosomic infants of non-obese mothers.

CONCLUSION

When both maternal obesity and macrosomia are present, adverse pregnancy outcomes are more common than when fetal macrosomia occurs in a woman of normal weight.

Maternal obesity and occurrence of fetal macrosomia: a systematic review and meta-analysis

OBJECTIVE

To determine a precise estimate for the contribution of maternal obesity to macrosomia.

DATA SOURCES

The search strategy included database searches in 2011 of PubMed, Medline (In-Process & Other Non-Indexed Citations and Ovid Medline, 1950-2011), and EMBASE Classic + EMBASE. Appropriate search terms were used for each database. Reference lists of retrieved articles and review articles were cross-referenced.

METHODS OF STUDY SELECTION

All studies that examined the relationship between maternal obesity (BMI ≥30 kg/m(2)) (pregravid or at 1st prenatal visit) and fetal macrosomia (birth weight ≥4000 g, ≥4500 g, or ≥90th percentile) were considered for inclusion.

TABULATION, INTEGRATION, AND RESULTS

Data regarding the outcomes of interest and study quality were independently extracted by two reviewers. Results from the meta-analysis showed that maternal obesity is associated with fetal overgrowth, defined as birth weight ≥ 4000 g (OR 2.17, 95% CI 1.92, 2.45), birth weight ≥4500 g (OR 2.77,95% CI 2.22, 3.45), and birth weight ≥90% ile for gestational age (OR 2.42, 95% CI 2.16, 2.72).

CONCLUSION

Maternal obesity appears to play a significant role in the development of fetal overgrowth. There is a critical need for effective personal and public health initiatives designed to decrease prepregnancy weight and optimize gestational weight gain.

Pre-pregnancy body mass index in relation to infant birth weight and offspring overweight/obesity: a systematic review and meta-analysis

BACKGROUND

Overweight/obesity in women of childbearing age is a serious public-health problem. In China, the incidence of maternal overweight/obesity has been increasing. However, there is not a meta-analysis to determine if pre-pregnancy body mass index (BMI) is related to infant birth weight (BW) and offspring overweight/obesity.

METHODS

Three electronic bibliographic databases (MEDLINE, EMBASE and CINAHL) were searched systematically from January 1970 to November 2012. The dichotomous data on pre-pregnancy overweight/obesity and BW or offspring overweight/obesity were extracted. Summary statistics (odds ratios, ORs) were used by Review Manager, version 5.1.7.

RESULTS

After screening 665 citations from three electronic databases, we included 45 studies (most of high or medium quality). Compared with normal-weight mothers, pre-pregnancy underweight increased the risk of small for gestational age (SGA) (odds ratios [OR], 1.81; 95% confidence interval [CI], 1.76-1.87); low BW (OR, 1.47; 95% CI, 1.27-1.71). Pre-pregnancy overweight/obesity increased the risk of being large for gestational age (LGA) (OR, 1.53; 95% CI, 1.44-1.63; and OR, 2.08; 95% CI; 1.95-2.23), high BW (OR, 1.53; 95% CI, 1.44-1.63; and OR, 2.00; 95% CI; 1.84-2.18), macrosomia (OR, 1.67; 95% CI, 1.42-1.97; and OR, 3.23; 95% CI, 2.39-4.37), and subsequent offspring overweight/obesity (OR, 1.95; 95% CI, 1.77-2.13; and OR, 3.06; 95% CI, 2.68-3.49), respectively. Sensitivity analyses revealed that sample size, study method, quality grade of study, source of pre-pregnancy BMI or BW had a strong impact on the association between pre-pregnancy obesity and LGA. No significant evidence of publication bias was observed.

CONCLUSIONS

Pre-pregnancy underweight increases the risk of SGA and LBW; pre-pregnancy overweight/obesity increases the risk of LGA, HBW, macrosomia, and subsequent offspring overweight/obesity. A potential effect modification by maternal age, ethnicity, gestational weight gain, as well as the role of gestational diseases should be addressed in future studies.

Contraceptive failures in overweight and obese combined hormonal contraceptive users

OBJECTIVE

To estimate weather contraceptive failure rates among combined oral contraceptive pill (OCP), patch, and vaginal ring users was associated with increasing body mass index (BMI).

METHODS

Females enrolled in a large contraceptive study offering the reversible method of their choice at no cost were followed-up for 2-3 years. We compared the failure rates (pregnancy) among users of the OCP, transdermal patch, and contraceptive vaginal ring stratified by BMI.

RESULTS

Among the 7,486 participants available for this analysis, 1,523 chose OCPs, patch, or ring at enrollment. Of the 334 unintended pregnancies, 128 were found to be a result of OCP, patch, or ring failure. Three-year failure rates were not different across BMI categories (BMI less than 25 8.44%, 95% confidence interval [CI] 6.1-11.5; BMI 25-30 11.03%, 95% CI 7.5-16.0; BMI more than 30 8.92%, 95% confidence interval 7.6-11.5). Increasing parity (hazard ratio [HR] 3.06, CI 1.31-7.18) and history of a previous unintended pregnancy (HR 2.82, CI 1.63-4.87), but not BMI, were significant risk factors for unintended pregnancy.

CONCLUSION

Overweight and obese females do not appear to be at increased risk for contraceptive failure when using the OCP, patch, or vaginal ring.

The Relation between Early Pregnancy Anthropometric Indices among Primiparous Women and Macrosomia

INTRODUCTION

The prevalence of obesity is increasing in both developed and developing nations. Body mass index (BMI) is the most common index for obesity assessment and its relation with most complications among non-pregnant and pregnant women is known. However, no study has evaluated the relation between abdominal obesity and macrosomia among pregnant women.

METHODS

In this prospective study, anthropometric indices including weight, height, and waist circumference (WC) of 1140 nulliparous pregnant women during their first trimester of pregnancy (6(th)-10(th) weeks) were measured by the researcher. According to the classification of the World Health Organization, women with BMI > 25 kg/m(2) were considered as overweight or obese. Abdominal obesity was defined as WC ≥ 88 cm. Finally, mothers were followed up and fetal macrosomia was recorded in a checklist. Data was analyzed in SPSS15.

RESULTS

The results showed that 77.5% of women aged 20-35 years and 92.7% were housewives. The mean (SD) values of BMI and WC were 24.32 (4.08) kg/m(2) and 81.84 (9.25) cm, respectively. The prevalence of overweight (BMI = 25-29.9 kg/m(2)) and obesity (BMI > 29.9 kg/m) was 27.6% and 8.8%, respectively. Abdominal obesity based on WC was found in 34.8% of the subjects.

CONCLUSION

Findings of this study revealed obesity in over one third of nulliparous pregnant women during their first trimester. Moreover, the high prevalence of macrosomia, in these women confirmed the importance of maternal education about obesity-related complications in order to change their lifestyle and prevent obesity.

Association between World Health Organization categories of body mass index and relative risks for weight-related pregnancy outcomes: a retrospective cohort study

OBJECTIVE

To analyse the dose-dependent effect of body mass index (BMI) categories for common pregnancy outcomes.

METHODS

A retrospective cohort study of all deliveries that occurred between 1 January 2005 and 31 December 2009 in a tertiary maternity centre, in Sydney Australia. Common pregnancy outcomes were analysed against World Health Organization (WHO) BMI categories using multiple logistic regression analysis.

RESULTS

From a total of 18,304 pregnancies, 9087 singleton pregnancies with complete data-sets were identified. Of these pregnancies, 4000 (44%) had a normal BMI, 470 (5.2%) were underweight, 2293 (25.2%) were overweight, 1316 (14.5%) were obese class I, 630 (6.9%) were obese class II and 378 (4.2%) were obese class III. Using the normal BMI category as the reference, there was a clear dose effect of BMI categories for hypertension (P < 0.001), pre-eclampsia (P < 0.001), caesarean section (P < 0.001), macrosomia (P < 0.001), large for gestational age (P < 0.001), small for gestational age (P < 0.001) and neonatal respiratory distress (P = 0.039). In contrast, despite a significant association with BMI (P < 0.001), a dose-dependent effect was not found for gestational diabetes.

CONCLUSION

The results of our study have important clinical significance as the data, using WHO BMI categories, more accurately help stratify risk assessment in a clinically relevant dose-dependent relationship.

Exercise guidelines in pregnancy: new perspectives

In 2002, the American College of Obstetricians and Gynecologists published exercise guidelines for pregnancy, which suggested that in the absence of medical or obstetric complications, 30 minutes or more of moderate exercise a day on most, if not all, days of the week is recommended for pregnant women. However, these guidelines did not define 'moderate intensity' or the specific amount of weekly caloric expenditure from physical activity required. Recent research has determined that increasing physical activity energy expenditure to a minimum of 16 metabolic equivalent task (MET) hours per week, or preferably 28 MET hours per week, and increasing exercise intensity to ≥60% of heart rate reserve during pregnancy, reduces the risk of gestational diabetes mellitus and perhaps hypertensive disorders of pregnancy (i.e. gestational hypertension and pre-eclampsia) compared with less vigorous exercise. To achieve the target expenditure of 28 MET hours per week, one could walk at 3.2 km per hour for 11.2 hours per week (2.5 METs, light intensity), or preferably exercise on a stationary bicycle for 4.7 hours per week (∼6-7 METs, vigorous intensity). The more vigorous the exercise, the less total time of exercise is required per week, resulting in ≥60% reduction in total exercise time compared with light intensity exercise. Light muscle strengthening performed over the second and third trimester of pregnancy has minimal effects on a newborn infant's body size and overall health. On the basis of this and other information, updated recommendations for exercise in pregnancy are suggested.