The Energy Requirements of Pregnant Rural Thai Women

Thongprasert, Kallaya (1986) The Energy Requirements of Pregnant Rural Thai Women. PhD thesis, University of Glasgow.

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The objective of this study was to investigate the energy requirements of pregnant rural Thai women. Altogether 44 women were followed from about 10 weeks gestation until term. They were all poor farmers who continued their agricultural work until delivery. The theordical calculation of the energy cost of pregnancy by Hytten & Leitch (1964) was based on the needs of nonpregnant women with an added amount estimated for the maternal physiological changes and for the growth and development of the fetus. This estimate of the energy cost of pregnancy has been used as a basis for recommendations during the last few decades. (FAO/WHO/UNU, 1985; FAO/WHO,1973; DHSS, 1969, etc). The calculation of the energy requirements of pregnancy in this study, however, was conducted by measuring the physiological changes in the mother as a whole, i.e. the changes in the maintenance metabolism (BMR); the changes in body composition, particularly the weight and fat gain; the changes in activity pattern of the mother, and the pregnancy outcome. In this study the progressive change in BMR was measured throughout pregnancy. The results showed a different pattern of change in BMR in the Thai women compared to the theoretical value. A slight change in early pregnancy was observed and thereafter a marked increase resulted in a total increment from 10 weeks until term at 24,000kcal. Estimates of the BMR of non-pregnant compared to the pregnant women at 10 weeks gestation provided no evidence to support the marked change in BMR during early pregnancy, as demonstrated by Hytten & Leitch (1964). Weight gain during pregnancy was found to be 8.9+/-2.9kg. Fat gain however was estimated by 3 different approaches 1) the changes of the skinfold thickness (biceps, triceps, subscapular and suprailiac); 2) the factorial method and 3) the changes of maternal body weight The average fat gain by these different methods was found to be 1. 2kg. The energy equivalent of this fat gain and the increment of maintenance energy resulted in 37,200kcal, plus an assumed energy equivalent of about 10,000kcal from fetal fat and fetal and maternal protein tissues. The energy cost of pregnancy was therefore 47,200kcal which was met by the estimated increase of energy intake of 56,900kcal. Energy intake was measured serially using the precise weighing method. The observers recorded the food intake for 5 consecutive days in every 6 weeks. The average energy intake was 1932+/-358kcal/d at about 10 weeks and showed a rise of 56,900kcal until term. Measurements of total daily energy expenditure were also made on these women simultaneously with the food intake. The average energy expenditure at 10 weeks was 1870+/-287kcal and the total increment from 10 weeks until term was 31,600kcal. The difference between the increment of intake and expenditure was found to be similar to the energy needed for the energy deposition in maternal adipose tissue stores and the product of conception. Changes in total energy expenditure resulted from changes in activity pattern and in the energy costs of individual activities. The women tended to spend more time sitting and less time in agricultural activity particularly in the second half of pregnancy. The daily energy expenditure however increased due to the assumption that the energy cost of activity per unit body weight was constant, which was true for BMR, at least until 33 weeks gestation. A significant decrease in energy cost of the weight bearing activities, i.e. walking on the treadmill at a fixed speed was observed during the second half of pregnancy. The results indicated an increased mechanical efficiency of the pregnant women. If this was the case for other activities, this would lower the increment of the calculated energy expenditure in this study. The energy cost of pregnancy in this group of women was 47,200kcal to cover the period of 30 weeks from 10 weeks until term. This was equivalent to an increment of 225kcal daily. The pregnancy outcome of this study was satisfactory taking into account the small stature of the women. These women gave birth to healthy babies with an average birth weight of 2.98+/-0.35kg and birth length of 0.48+/-0.02m. In order to form a basis for recommending the energy requirements for pregnant rural women, more information is needed particularly from conception to 10 weeks of pregnancy.

Item Type: Thesis (PhD)
Qualification Level: Doctoral
Keywords: Physiology, Obstetrics
Date of Award: 1986
Depositing User: Enlighten Team
Unique ID: glathesis:1986-77415
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 14 Jan 2020 09:09
Last Modified: 14 Jan 2020 09:09

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