Energy requirements during pregnancy and lactation

Abstract

Objective: To estimate the energy requirements of pregnant and lactating women consistent with optimal pregnancy outcome and adequate milk production. Design: Total energy cost of pregnancy was estimated using the factorial approach from pregnancy-induced increments in basal metabolic rate measured by respiratory calorimetry or from increments in total energy expenditure measured by the doubly labelled water method, plus energy deposition attributed to protein and fat accretion during pregnancy. Setting: Database on changes in basal metabolic rate and total energy expenditure during pregnancy, and increments in protein based on measurements of total body potassium, and fat derived from multi-compartment body composition models was compiled. Energy requirements during lactation were derived from rates of milk production, energy density of human milk, and energy mobilisation from tissues. Subjects: Healthy pregnant and lactating women. Results: The estimated total cost of pregnancy for women with a mean gestational weight gain of 12.0 kg, was 321 or 325 MJ, distributed as 375, 1200, 1950 kJ day 21 , for the first, second and third trimesters, respectively. For exclusive breastfeeding, the energy cost of lactation was 2.62 MJ day 21 based on a mean milk production of 749 g day 21, energy density of milk of 2.8 kJ g 21, and energetic efficiency of 0.80. In well-nourished women, this may be subsidised by energy mobilisation from tissues on the order of 0.72 MJ day 21, resulting in a net increment of 1.9 MJ day 21 over nonpregnant, non-lactating energy requirements. Conclusions: Recommendations for energy intake of pregnant and lactating women should be updated based on recently available data.

Metabolic hypothesis for human altriciality

“…During pregnancy, metabolic rates in human mothers quickly approach this limit, with daily energy expenditures two times greater than prepregnancy BMR by the sixth month (42,43). Throughout the rest of pregnancy and through the first months of nursing, maternal metabolic rates stay at 2.0× BMR but never climb higher, even in populations where strenuous manual labor is common among pregnant women and new mothers (40,42,43). Instead, among both affluent and energystressed populations, women commonly use a range of behavioral and physiological strategies to reduce daily energy needs during pregnancy and lactation (44).…”

“…[Tour de France cyclists can approach 4-5× BMR, but this is not typical for humans, which generally do not exhibit sustained energy expenditures in excess of 2.5× BMR (40).] During pregnancy, metabolic rates in human mothers quickly approach this limit, with daily energy expenditures two times greater than prepregnancy BMR by the sixth month (42,43). Throughout the rest of pregnancy and through the first months of nursing, maternal metabolic rates stay at 2.0× BMR but never climb higher, even in populations where strenuous manual labor is common among pregnant women and new mothers (40,42,43).…”

Energy expenditure by multisensor armband in overweight and obese lactating women validated by doubly labeled water

“…In lactating women, the energy spent for milk production is included in TEE measured by DLW; however this is not the case for milk energy output. The energy spent for milk production can be estimated to around a maximum of 165 kcal/day (19). It is unlikely that the SWA Pro 2 is able to detect the extra energy expenditure from milk production.…”

“…However, this implicated only four out of 62 women and the maximum contribution of energy from non-breastmilk sources was 20% of infant's energy needs. Assuming a minimal efficiency in milk production of 80%, a REE of 1,500 kcal will be increased by 165 kcal (11% (19)) in those who exclusively breastfeed and 132 kcal in those who were complementary feeding, a difference that can be considered minimal. Major strengths of the study are the way the DLW was conducted and analyzed, the study of an under-represented group, the high compliance in the women with 97% wearing time for SWA Pro 2 and the sample size, which is considerably larger than previous validation studies with SWA and DLW (7,10).…”

Evidence to Suggest that Women’s Sexual Behavior is Influenced by Hip Width Rather than Waist-to-Hip Ratio

“…Nonetheless, the conflicting demands of each have created an obstetric dilemma whereby childbirth is rendered difficult as women's hips are only just wide enough to allow an infant to be born (Rosenberg, 1992;Rosenberg & Trevathan, 2002;Wittman & Wall, 2007). Further complications are caused by neonate size remaining relatively constant regardless of variations in maternal size (Butte & King, 2005;Mohanty et al, 2006), which places those with narrow pelvic outlets at greatest risk of Cephalopelvic Disproportion (CPD) (Stålberg, Bodestedt, Lyrenäs, & Axelsson, 2006;Thurnau, Hales, & Morgan, 1992).…”