Body composition measurement by air displacement plethysmography in pregnancy: Comparison of predicted versus measured thoracic gas volume

Weight gain and body composition during pregnancy: a randomised pilot trial with probiotics and/or fish oil

We evaluated the effects of fish oil and/or probiotic supplementation in a randomised placebo-controlled intervention pilot trial on gestational weight gain (GWG) and body composition. Additionally, the influence of gestational diabetes (GDM) on GWG and body composition was assessed. We randomised 439 overweight women into intervention groups: fish oil + placebo, probiotics + placebo, fish oil + probiotics and placebo + placebo (fish oil: 1·9 g DHA and 0·22 g EPA and probiotics: Lactobacillus rhamnosus HN001 and Bifidobacterium animalis ssp. lactis 420, 1010 colony-forming units each). GDM was diagnosed with oral glucose tolerance test. Body composition was measured with air displacement plethysmography at randomisation (mean 13·9) and in late pregnancy (mean 35·2 gestational weeks). Intervention did not influence mean GWG or change in body fat mass/percentage (P > 0·17). Body composition in early pregnancy did not differ between the women who did or did not develop GDM (adjusted P > 0·23). Compared with the normoglycaemic women (n 278), women diagnosed with GDM (n 119) gained less weight (7·7 (sd 0·4) v. 9·3 (sd 0·4) kg, adjusted mean difference -1·66 (95 % CI -2·52, -0·80) and fat mass (0·4 (sd 0·4) v. 1·8 (sd 0·3) kg, adjusted mean difference -1·43 (95 % CI -2·19, -0·67) during the follow-up. In conclusion, adiposity of pregnant overweight women was not affected by supplementation with fish oil and/or probiotics, nor did it predict the development of GDM. However, adiposity was reduced in women with GDM compared with normoglycaemic women irrespective of the dietary intervention.

Amant M, Beyl RA, Ravussin E, Redman LM. Increased Energy Intake After Pregnancy Determines Postpartum Weight Retention in Women With Obesity

CONTEXT

This study was designed to understand causes and critical periods for postpartum weight retention by characterizing changes in body composition, energy intake, energy expenditure and physical activity in women with obesity during pregnancy and postpartum.

DESIGN

In this prospective, observational cohort study, body composition (plethysmography), energy expenditure (doubly labeled water, whole-body room calorimetry), physical activity (accelerometry), metabolic biomarkers, and eating behaviors were measured. Energy intake was calculated by the intake-balance method for pregnancy, and for 2 postpartum periods (0 to 6 months and 6 to 12 months).

RESULTS

During the 18-month observation period, weight loss occurred in 16 (43%) women (mean ± SEM, -4.9 ± 1.6 kg) and weight retention occurred in 21 (57%) women (+8.6 ± 1.4 kg). Comparing women with postpartum weight loss and weight retention, changes in body weight were not different during pregnancy (6.9 ± 1.0 vs 9.5 ± 0.9 kg, P = 0.06). After pregnancy, women with postpartum weight loss lost -3.6 ± 1.8 kg fat mass whereas women with weight retention gained 6.2 ± 1.7 kg fat mass (P < 0.001). Women with postpartum weight loss reduced energy intake during the postpartum period (compared with during pregnancy) by 300 kcal/d (1255 kJ/d), while women with weight retention increased energy intake by 250 kcal/d (1046 kJ/d, P < 0.005). There were no differences in the duration of breastfeeding, eating behavior, or metabolic biomarkers.

CONCLUSIONS

Postpartum weight gain was the result of increased energy intake after pregnancy rather than decreased energy expenditure. Dietary intake recommendations are needed for women with obesity during the postpartum period, and women should be educated on the risk of overeating after pregnancy.

Body Composition During Pregnancy Differs by Obesity Class

OBJECTIVE

The aim of this study is to characterize changes in body composition during pregnancy in women with obesity.

METHODS

Fifty-four healthy women with obesity (class 1, 30-34.9 kg/m² : n = 25; class 2, 35-39.9 kg/m² : n = 21; class 3, ≥ 40.0 kg/m² : n = 8) expecting a singleton pregnancy were studied. Body composition was measured in early pregnancy (13-16 weeks), midpregnancy (24-27 weeks), and late pregnancy (35-37 weeks) using air displacement plethysmography, stable isotopes, and skinfold thickness measurements. Fasting glucose, insulin, and leptin were measured.

RESULTS

The gain in fat-free mass was lower in the second trimester compared with the third (2.7 ± 0.2 to 5.3 ± 0.2 kg; P < 0.001), whereas fat mass accumulation declined over time (0.6 ± 0.3 to -0.7 ± 0.4 kg; P = 0.005). Women with class 1 and 2 obesity gained 1.1 ± 0.7 kg of fat mass during pregnancy, while women with class 3 obesity lost 4.1 ± 0.6 kg (both P < 0.001). The difference in fat accumulation between obesity classes was observed only in the second trimester (P = 0.02). Gestational weight gain was associated positively with changes in plasma concentrations of insulin, leptin, and insulin resistance (all P < 0.01).

CONCLUSIONS

Gestational weight gain in pregnancy differs by obesity class and trimester. Women with class 3 obesity gain less body weight and fat mass. Fat mass gain is most likely preventable in the second trimester.