Early pregnancy changes in hemodynamics and volume homeostasis are consecutive adjustments triggered by a primary fall in systemic vascular tone

Duvekot, Johannes J.; Cheriex, Emile C.; Pieters, Frans; Menheere, P. P. C. A.; Peeters, Louis L.H.

doi:10.1016/0002-9378(93)90405-8

Cited by 386 publications

(258 citation statements)

References 26 publications

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“…In turn, this would lead to a compensatory activation of volume-restoring mechanisms, such as renal vasodilatation and activation of the renin-angiotensin-aldosterone system, both of which occur before full placentation. 4,5,22 Placental estrogen may also play a role in volume expansion through hepatic stimulation of angiotensinogen synthesis 23 and by activation of NO synthase activity. 24 For these reasons, changes in the renin-angiotensin-aldosterone system and in estrogen concentrations are considered primary modulators of plasma volume expansion during pregnancy.…”

Section: Discussionmentioning

confidence: 99%

Time Course of Maternal Plasma Volume and Hormonal Changes in Women With Preeclampsia or Fetal Growth Restriction

et al. 2006

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Abstract-We tested the hypothesis that women with idiopathic fetal growth restriction (FGR) or preeclampsia (PE) have lower concentrations of some water-retaining hormones, such as aldosterone and estradiol, either preceding or concomitant with the onset of the reduced plasma volume described in these women. Plasma volume and serum concentrations of estradiol, progesterone, and aldosterone were measured serially at monthly intervals in 135 pregnant women from week 10 until term. Twenty-three developed idiopathic FGR, 17 had PE, and 95 remained normotensive and delivered normal-size infants (controls). Changes over time for each variable were studied using mixed models.Maternal age, parity, and weight/height at term were similar in all of the groups. Birth weight, body length, and ponderal index were lower in FGR and PE than in controls. Plasma volume increased throughout pregnancy in controls but was lower in FGR and PE from week 14 to 17 until term. Aldosterone values were lower in PE from week 26 to 29 onwards and in FGR after week 34. Progesterone concentrations were higher in PE than either control or FGR from week 18 to 21 until term. In contrast, FGR pregnancies had reduced progesterone and estradiol concentrations after week 34. Progesterone:estradiol ratio was significantly higher only in the PE group. In mothers with idiopathic FGR or PE, less expansion in plasma volume occurred before alterations in hormonal concentrations. We speculate that the early rise in progesterone may have a pathogenic role in the development of preeclampsia. Key Words: blood Ⅲ aldosterone Ⅲ preeclampsia Ⅲ estrogen P reeclampsia (PE) and fetal growth restriction (FGR) are frequent disorders of pregnancy and a leading cause of prenatal morbidity and mortality. In near-term pregnant women with either PE or FGR, we demonstrated lower plasma volume expansion, reduced cardiac output, and an increased total peripheral vascular resistance when compared with normotensive women who gave birth to normal-size infants. 1-3 Volume expansion during normal pregnancy seems to be secondary to renal and systemic vasodilatation that would activate the renin-angiotensin-aldosterone system that, in turn, would cause renal sodium and water retention. 4 -6 Estrogen production may also have a role in plasma volume expansion by stimulating hepatic angiotensinogen synthesis. 5,7 According to this proposed pathway for volume expansion, in the present study we tested the hypothesis that women with PE or FGR would have lower serum aldosterone and estradiol concentrations either preceding or concomitant with the onset of the reduced plasma volume. We measured plasma volume and hormonal concentrations in initially healthy pregnant women from weeks 10 to 13 until near term. After delivery, we compared the time course of these changes in control, FGR, and PE women. MethodsParticipants were women attending 2 prenatal clinics of the Southeastern Health Service of Santiago, Chile (Alejandro del Río and La Granja). These women belonged to a low-income population ...

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Section: Discussionmentioning

confidence: 99%

Time Course of Maternal Plasma Volume and Hormonal Changes in Women With Preeclampsia or Fetal Growth Restriction

et al. 2006

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“…During the course of pregnancy, there are a large number of pregnancyinduced hemodynamic changes in the cardiovascular system, which are summarized in Table 5 ( [57][58][59][60][61][62][63][64]. During the peripartum period, further changes are noted as well (65)(66)(67)(68).…”

Section: Hemodynamic Changes Of Normal Pregnancy and Precipitation Of Hfmentioning

confidence: 99%

The 2010 Canadian Cardiovascular Society guidelines for the diagnosis and management of heart failure update: Heart failure in ethnic minority populations, heart failure and pregnancy, disease management, and quality improvement/assurance programs

Howlett¹,

McKelvie²,

Costigan³

et al. 2010

Canadian Journal of Cardiology

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“…Despite these adaptations, and because of a marked reduction in systemic vascular resistance, blood pressure (BP) falls (1,2). One of the earliest and most dramatic changes is the increase in renal plasma flow (RPF) and GFR due to renal vasodilation (3).…”

mentioning

confidence: 99%

“…Another striking change is the fall in plasma osmolality (P osm ) (3). Both adaptations are hallmarks of an "optimal" pregnancy, and the causes may be linked (1,3). The rat is useful to study mechanisms underlying renal adaptations to pregnancy because, similar to humans, rats exhibit renal vasodilation, hyperfiltration, and a fall in P osm during gestation.…”

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confidence: 99%

An Emerging Role for Relaxin as a Renal Vasodilator

Sasser

Lindheimer

Baylis

2006

Journal of the American Society of Nephrology

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S triking renal and cardiovascular adaptations occur early in human pregnancy, including increases in intravascular volume and cardiac output. Despite these adaptations, and because of a marked reduction in systemic vascular resistance, blood pressure (BP) falls (1,2). One of the earliest and most dramatic changes is the increase in renal plasma flow (RPF) and GFR due to renal vasodilation (3). Animal studies indicate a role for the ovarian hormone relaxin (RLX) (4,5), and the report by Smith et al. (6) in this issue of JASN expands on this literature by reporting on the renal hemodynamic effect of acute RLX infusion in normal men and nonpregnant women.In human pregnancy, GFR and RPF are maximally increased (50% or more) by midterm, with the rise in RPF exceeding GFR; thus, the filtration fraction decreases. As expected, plasma creatinine declines, such that values Ͼ0.8 mg/dl are considered abnormal. Another striking change is the fall in plasma osmolality (P osm ) (3). Both adaptations are hallmarks of an "optimal" pregnancy, and the causes may be linked (1,3). The rat is useful to study mechanisms underlying renal adaptations to pregnancy because, similar to humans, rats exhibit renal vasodilation, hyperfiltration, and a fall in P osm during gestation. Micropuncture studies showed that the increase in GFR and RPF is due to parallel reductions in both afferent and efferent arteriolar resistances with no change in glomerular BP (3). Of note, studies using fractional dextran clearances combined with mathematical modeling suggest this to be the case in human gestation as well (3).The factors responsible for the increased gestational GFR and RPF are not entirely clear, although there is evidence of activation of the vasodilatory nitric oxide-cGMP signaling pathway (3). The renal vasodilatory stimulus is likely maternal in origin, because similar changes are observed in pseudopregnant rats (3) and on a smaller scale during the luteal phase of the menstrual cycle (2,3).As mentioned above, studies in the rat have identified ovarian RLX as an important mediator of renal vasodilation, hyperfiltration, and osmoregulation. Chronic administration of RLX in virgin female rats causes renal vasodilation, increased GFR, and decreased P osm with no change in BP (7). The RLX-induced increase in GFR and RPF and fall in P osm is independent of other ovarian hormones as this effect was also observed in ovariectomized female and male rats (4,7).Relaxin appears to be essential for the renovascular adaptations of rat pregnancy. A key study by Novak et al. demonstrated that removal of circulating RLX by ovariectomy or by administration of neutralizing antibodies to rat RLX abolished the rise in GFR and RPF and fall in P osm and prevented the reduction in myogenic activity in small renal arteries in midterm pregnant rats (5).In women, RLX levels rise during the luteal phase of the menstrual cycle, when GFR is at its maximum, and increase further when stimulated by human chorionic gonadotrophin during early pregnancy (8), concurrent wit...

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Early pregnancy changes in hemodynamics and volume homeostasis are consecutive adjustments triggered by a primary fall in systemic vascular tone

Cited by 386 publications

References 26 publications

Time Course of Maternal Plasma Volume and Hormonal Changes in Women With Preeclampsia or Fetal Growth Restriction

Time Course of Maternal Plasma Volume and Hormonal Changes in Women With Preeclampsia or Fetal Growth Restriction

The 2010 Canadian Cardiovascular Society guidelines for the diagnosis and management of heart failure update: Heart failure in ethnic minority populations, heart failure and pregnancy, disease management, and quality improvement/assurance programs

An Emerging Role for Relaxin as a Renal Vasodilator

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