Abstracts of theses and treatises
Rae C (1989) Maternal nutritional status among Aborigines in the Northern Territory: impact on birthweight. Unpublished Master of Public Health thesis, University of Sydney, Sydney, New South Wales.
This prospective study of pregnancy and outcome was conducted in two coastal Aboriginal communities from January 1984 to June 1986. It was designed to test the hypothesis that inadequate maternal nutrition status, prior to and during pregnancy, contributed to the high prevalence of low birth weight (LBW), less than 2500g and the low mean birth weight among Aboriginal infants in the northern ares of the Northern Territory.
Chronic malnutrition, evidenced by low prepregnant weight, low Body Mass Index (BMI), low gestation weight gain and anaemia, was observed among the women of child bearing age in both communities.
Almost half of the women had a prepregnant weight less than the 3rd centile or were categorised as very underweight with a BMI of less than 18. The mean gestation weight gain was between 8kg and 9kg, and anaemia was diagnosed in 40% of pregnancies.
Other indices of poor health status and risk factors for LBW were also observed among this population. One third of the pregnancies were to adolescent mothers and half of the women had previously delivered a LBW infant. Forty percent were known to have smoked cigarettes, but only one woman consumed alcohol during pregnancy. Infections of the skin, respirator and urinary tract, were found in 70% of pregnant women.
Attendance for prenatal care varied between the communities. At one community nearly two thirds had attended in the first trimester and the remainder during the second trimester. In the other community, more than one third did not attend until the third trimester or at term.
The prevalence of LBW was 23.7% and 2.13% for the two communities. The mean birth weights were 2816g and 2932g respectively. When weight was adjusted for gestational age, 27.7% of the infants could be described as small for gestational age (SGA). Approximately 13% of all infants were delivered preterm (<37 weeks gestation).
These 1980s data were compared to similar data collected prospectively in the same communities during the 1970s. In one community there had been little change in the prevalence of LBW, mean birth weight or maternal nutritional status over the 15 year period. In the second community there was a marked reduction in the prevalence of LBW, significant increase in mean birth weight as well as increased prepregnant weight and gestational weight gain amongst the mothers.
Generalised linear modelling of the data indicated that the women at highest risk for small for gestational age infants in this population were: those attending for prenatal care later than 20 weeks, those with a prepregnant weight less than the 3rd centile (about 43kg), those whose weight gain was less than 8kg and those who were aged greater than 19 years and were parity less than 4.
Prepregnant weight was found to be a significant independent determinant of outcome whereas gestational weight gain appeared to modify the effect of prepregnant weight. Women with low prepregnant weight who gained more than the mean gestational weight gain delivered significantly heavier infants. Prenatal care as a risk factor is unlikely to exert any independent casual effect but probably encompasses the presence of other important risk factors in the women with minimal or no care.
There are important public health implications from the results of the study. Firstly, the need to maximise early prenatal care attendance by Aboriginal women in remote communities to enable identification and modification of conditions likely to compromise the health of mother and infant. Secondly, to introduce nutritional assessment and monitoring into prenatal care protocols with evaluation of their use. Thirdly, evaluation of strategies to improve maternal nutrition by increased weight gain during pregnancy with the long term goal of reducing LBW and increasing the mean birth weight of Aboriginal infants.
For further information on this subject look in the Australian Indigenous HealthInfoNet Bibliography or return to the theses page.
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