Leptin levels in the hypertensive black African parturient.
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Date
2001
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Abstract
Background: Leptin is a new adipose-derived hormone discovered in 1994. It is
vital in energy balance and weight regulation in humans. During pregnancy the
placenta is an extra source of leptin. The role of leptin in pregnancy is not
established. This has generated a lot of interest in leptin research in pregnancy.
Leptin is being examined in pathological states that may have origin in adipose
tissue and the placenta such as pre-eclampsia, intrauterine growth restriction and
obesity.
Aim and Method: This study measured concentrations of serum leptin in Black
African women during late pregnancy in 68 women with pre-eclampsia, 92 healthy
normotensive pregnant women and in 32 healthy non-pregnant women. In each
group leptin levels were compared between obese (body mass index, BMI = or > than
30 kgm-2) and lean women. Serum leptin concentrations were measured by
radioimmunoassay (RIA) technique.
Results: Serum leptin levels were higher in pregnancy compared to non-pregnant
women (26.66+/-16.13 ng/ml, 25.89+/-15.83 ng/ml vs 17.97+/-11.98 ng/ml, p=0.02). This
is due to firstly, the extra fat accumulated as part of the maternal adaptation to
pregnancy and secondlv, to the placenta-derived leptin. Other pregnancy hormones
such as insulin, hcG, prolactin and oestrogen may modulate the serum levels of leptin in
pregnancy.
Simple anthropometric parameters (weight, BMI, circumferences of the mid upper arm
(MAC), waist (WC), hip (HC), and thigh (TC) and waist-hip ratio (WHR)) were used to
explore the relationship between leptin concentrations and obesity. All the parameters
showed a positive correlation with serum leptin concentration in all the groups with the
exception of WHR. Weight and BMI showed the greatest correlation both in pregnant
(r=0.61 and r=0.58, respectively, p<0.001) and non-pregnant (r=0.74 and 0.79,
respectively, p<0.001) women.
However we did not find a significant difference in the concentrations of leptin between
women with and those without pre-eclampsia (26.66 ng/ml vs 25.89 ng/ml, p=0.95). This
probably means that adiposity is the predominant factor influencing levels of leptin in
pregnancy. The other factors mentioned above play only a minor role. Indeed the mean
serum leptin levels were higher in obese compared to lean women in both pregnant and
non-pregnant women.
Conclusion: Pregnancy is a hyperleptinaemic state. There is no difference in serum
leptin levels between women with pre-eclampsia and healthy normotensive pregnant
women. Serum leptin concentration is largely determined by the degree of adiposity both
in and outside pregnancy.
Description
Thesis (M.Med.)-University of Natal, Durban, 2001.
Keywords
Hormones--Physiology., Hypertension in pregnancy., Leptin., Preeclampsia., Women, Black., Theses--Obstetrics and gynaecology.