Morphofunctional Cardiac Changes in Singleton and Twin Pregnancies: A Longitudinal Cohort Study

Abstract

Background: This study aimed to compare the echocardiographic changes and cardiac biomarkers between women with singleton and twin pregnancies.Methods: From April 2014 to March 2016, this longitudinal cohort study invited pregnant women who were scheduled to give birth at Hokkaido University Hospital. We analyzed prospectively collected data on simultaneously determined echocardiographic parameters and blood cardiac markers of 44 women with singleton and 22 women with twin pregnancies. Furthermore, we tested the mixed-effect models for echocardiographic parameters and cardiac biomarkers.Results: During the third trimester and immediately postpartum (within 1 week after childbirth), the mean left atrial volume index and brain natriuretic peptide (BNP) level were significantly higher in women with twin pregnancies than in those with singleton pregnancies. Women with twin pregnancies also had significantly smaller second-trimester inferior vena cava diameters and significantly higher third-trimester creatinine levels than those with singleton pregnancies. BNP positively correlated with the left atrial volume index (β = 0.49, p < 0.01) and the ratio of early diastolic transmitral to mitral annular velocity (E/e') (β = 0.41, p < 0.01). At 1 month after childbirth in women with singleton pregnancies, BNP and N-terminal precursor protein BNP (NT-proBNP) fragments immediately postpartum negatively correlated with the later E/e' (r = −0.33, p = 0.02 and r = −0.36, p < 0.01, respectively).Conclusions: The intravascular cardiac load reached maximum within 1 week after childbirth and was greater in women with twin pregnancies than in those with singleton pregnancies. BNP/NT-proBNP significantly positively correlated with LA volume index and E/e'. In women with singleton pregnancies, BNP secreted immediately after childbirth might improve the diastolic functions 1 month after childbirth.

Maternal echocardiographic changes in twin pregnancies with and without pre‐eclampsia

“…Consistent with our results, LVM and SV were higher and increased with advancing gestation in uncomplicated twin compared with uncomplicated singleton pregnancies, whereas peripheral vascular indices, such as TVRi, were lower in twin compared with singleton cases. In a longitudinal study including 30 uncomplicated twin pregnancies, a significant progressive deterioration of left ventricular diastolic function (reduction of E‐wave velocity, increase of A‐wave and reduction of lateral and septal e′) was observed from the first to the third trimester; however, conflicting results have been reported in other similar studies 10,15,25,26 . When twin pregnancies that developed HDP or delivered a small‐for‐gestational‐age neonate were compared with uncomplicated twin pregnancies, the only significant cardiovascular change was that TVR was higher in pathological pregnancies.…”

“…Most echocardiographic studies have investigated the difference between uncomplicated twin and singleton pregnancies 10,11,[13][14][15]25 . Consistent with our results, LVM and SV were higher and increased with advancing gestation in uncomplicated twin compared with uncomplicated singleton pregnancies, whereas peripheral vascular indices, such as TVRi, were lower in twin compared with singleton cases.…”

“…Several studies using maternal echocardiography have provided important information regarding the considerable impact of pregnancy-related changes on the maternal cardiovascular system in uncomplicated and hypertensive singleton pregnancies [7][8][9] . Conversely, only a few studies have been published on the effect of twinning on maternal cardiovascular adaptation to pregnancy [10][11][12][13][14][15] . In uncomplicated twin pregnancy compared with uncomplicated singleton pregnancy, maternal cardiac function and hemodynamic changes appear to be more pronounced, presumably in order to supply the higher uteroplacental demand.…”

“…In uncomplicated twin pregnancy compared with uncomplicated singleton pregnancy, maternal cardiac function and hemodynamic changes appear to be more pronounced, presumably in order to supply the higher uteroplacental demand. However, no study has compared maternal cardiac changes in multiple pregnancy with those in singleton pregnancy with HDP 11,[13][14][15] .…”