Changes in maternal heart dimensions and plasma atrial natriuretic peptide levels in the early puerperium of normal and pre-eclamptic pregnancies.
OBJECTIVE
To measure plasma atrial natriuretic peptide (ANP) in relation to maternal haemodynamics and body fluid balance in the early puerperium following uncomplicated pregnancy and pre-eclampsia.


METHODS
A longitudinal study from late pregnancy and into the early postpartum period (days 1 to 3 and days 4 to 6) compared with nonpregnant controls.


METHODS
Eleven women with uncomplicated pregnancies, 12 women with pre-eclampsia and 12 healthy, nonpregnant women.


METHODS
Maternal heart dimensions determined by M-mode echocardiography, concentrations of ANP, and daily urine output and sodium excretion.


RESULTS
After delivery increases in left atrial dimensions, represented as mean (SEM), from 33.2 (1.6) to 37.7 (1.7) mm and ANP levels from 7.9 (1.1) to 19.0 (2.7) pmol/L were observed at 1-3 days postpartum in normal pregnant women, but we were not able to demonstrate a significant increase in diuresis and natriuresis. In the third trimester left atrial dimensions (38.4 (1.2) mm) and ANP levels (15.4 (2.2) pmol/L) were greater in pre-eclampsia. ANP levels rose further in pre-eclamptic women in the early puerperium (27.4 (7.4) pmol/L) with an increase in diuresis and natriuresis, while left atrial dimensions did not change significantly (39.4 (1.7) mm). A pericardial effusion was found in 11 pre-eclamptic but in only three healthy pregnant women.


CONCLUSIONS
A concommitant increase in left atrial dimensions and ANP in the early puerperium following uncomplicated pregnancies is consistent with the mechanism of atrial stretch as a stimulus for ANP release, although the biological significance of this finding remained unclear. A significantly higher release of ANP in the early puerperium after pregnancies complicated by pre-eclampsia may be a mechanism which promotes the renal elimination of excessive body fluids and sodium.
Pouta
A M
AM
Department of Obstetrics and Gynaecology, University of Oulu, Finland.
Räsänen
J P
JP
Airaksinen
K E
KE
Vuolteenaho
O J
OJ
Laatikainen
T J
TJ
D000328:Adult; D009320:Atrial Natriuretic Factor / Q000097:blood*; D004452:Echocardiography; D005260:Female; D006325:Heart Atria / Q000033:anatomy & histology*; D006801:Humans; D008137:Longitudinal Studies; D049590:Postpartum Period / Q000097:blood; D011225:Pre-Eclampsia / Q000097:blood*; D011247:Pregnancy / Q000097:blood; D011263:Pregnancy Trimester, Third
D009320:Atrial Natriuretic Factor