Correlation of Hormones with Lipid and Lipoprotein Levels During Normal Pregnancy and Postpartum*

Abstract

In a comprehensive study the concentrations of plasma lipids and lipo- and apolipoproteins were measured in 24 nonpregnant women (control) and longitudinally in 42 women throughout gestation and postpartum. The results were correlated with hCG, 17 beta-estradiol (E2), progesterone (PG), human placental lactogen (hPL), and insulin levels by time series analysis. Insulin concentrations were constant until week 25 and increased thereafter. Plasma E2, PG, and hPL as well as plasma lipid levels rose continuously during gestation. Apolipoproteins AI, AII, and B concentrations increased until weeks 25, 28, and 32, respectively, and remained constant until term. Low density lipoprotein cholesterol reached maximum levels at week 36. High density lipoprotein cholesterol exhibited a triphasic behavior, with maximum levels at week 25, a fall until week 32, and maintenance of the level until term. Time series analysis revealed positive correlations with E2, PG, and hPL. These results provide evidence that apoprotein concentrations undergo pronounced serial changes during gestation, which in part might be due to the effect of E2. Furthermore, the importance of hPL as a determinant of the plasma levels of total and free cholesterol, triglycerides, and phospholipids is now documented.

Effect of Acipimox on Plasma Lipids and Glucose/Insulin in Pregnant Rats

“…Similar results have been shown by our group with fenofibrate, another TG-reducing compound [17]. The differences in the rebound effect between pregnant and virgin animals could be secondary to the high lipolytic activity present at the end of gestation, therefore the equilibrium between the inhibitory effects of acipimox on lipolysis are overrun by the lipolytic effects of the high levels of (hPL) or the insulin resistance at late pregnancy [5,6]. During late gestation, one of the main sources of fuel energy for the maternal tissues are FFA derived from lipolysis of very-low-density lipoprotein (VLDL)-TG [4].…”

“…Some tissues use fatty acids as fuel, sparing glucose for the fast-growing fetus and those maternal tissues that can only use glucose as fuel energy [4]. The mechanisms involved in this elevated lipolytic activity are uncertain, but the rising levels of placental lactogen and the insulin resistance during late pregnancy seem to play a relevant role [5][6][7].The enhanced availability of FFA to the liver seems to contribute to the increased production of TG by this organ [8] and therefore to the development of maternal hypertriglyceridemia. Exaggerated increment of TG in maternal circulation may be involved in some of the pregnancy-induced complications, including eclampsia [9] and insulin resistance that would cause the development of gestational diabetes [7], 2 of the most common pregnancy-induced complications.…”

“…Some tissues use fatty acids as fuel, sparing glucose for the fast-growing fetus and those maternal tissues that can only use glucose as fuel energy [4]. The mechanisms involved in this elevated lipolytic activity are uncertain, but the rising levels of placental lactogen and the insulin resistance during late pregnancy seem to play a relevant role [5][6][7].…”

Ethnic differences in maternal total cholesterol and triglyceride levels during pregnancy: the contribution of demographics, behavioural factors and clinical characteristics

“…When pregnancy progresses, specific changes in total cholesterol (TC), fractionated cholesterol and TG occur that leads to physiologically increased lipid levels towards the end of pregnancy (Sattar et al, 1997;Brizzi et al, 1999). It is thought that progressive increase in oestrogen levels during gestation induces most of these alterations in lipoprotein metabolism (Desoye et al, 1987), which suggests the necessity of these metabolic changes for pregnancy maintenance and foetal growth. Indeed, reduced maternal TC levels are associated with intrauterine growth restriction and preterm delivery (Sattar et al, 1999;Edison et al, 2007).…”

Leptin and phospholipid-esterified docosahexaenoic acid concentrations in plasma of women: observations during pregnancy and lactation

“…The most substantial increases in plasma phospholipids and other lipid fractions occur after the ®rst 10 weeks of pregnancy (Desoye et al, 1987;Potter & Nestel, 1979). When we studied the relations between pre-pregnancy BMI, leptin concentration and the amount of phospholipid-associated fatty acids at 36 weeks of gestation and during the subsequent postpartum period, the total amount of fatty acids in plasma phospholipids no longer related to either BMI or leptin concentration.…”