First-trimester maternal haemodynamic adaptation to pregnancy and placental, embryonic and fetal development: the prospective observational Rotterdam Periconception cohort

At mid-gestation, markers of placental function rather than maternal cardiac function are stronger determinants of birthweight

BACKGROUND

The role of maternal cardiac and hemodynamic assessment during normal and complicated pregnancies has gained attention during the last few years. Some researchers suggested that the manifestation of complications in pregnancy suffering from impaired placentation is mainly driven by preexisting cardiac changes, identifiable at an early stage by echocardiographic and hemodynamic assessment. It is therefore of great importance to determine the link between placental perfusion and maternal cardiac function and hemodynamics. Also, the impact of maternal cardiac function on birth weight has not been thoroughly studied.

OBJECTIVE

To elucidate the possible association of maternal cardiovascular indices with placental perfusion at mid-gestation and birthweight.

STUDY DESIGN

Prospective study on women with singleton pregnancies attending Kings' College Hospital, London, UK for a routine hospital visit at 19 to 24 weeks of gestation. We recorded maternal characteristics and medical history, measured mean arterial pressure, heart rate, uterine artery pulsatility index, umbilical artery pulsatility index, middle cerebral artery pulsatility index, and serum placental growth factor. We also performed maternal echocardiogram to assess cardiac output and peripheral vascular resistance as well as indices of diastolic and systolic cardiac function. Multivariable regression modeling was used.

RESULTS

Our cohort included 4006 women. Higher uterine artery pulsatility index values were associated with lower mean arterial pressure, heart rate, and left ventricular systolic function, after adjustment for maternal characteristics and subsequent development of hypertensive disorders of pregnancy and gestational diabetes mellitus. In a multivariable approach that explained 17.9% of the variance of the birthweight, we found that some cardiovascular indices provided small but significant contribution to the model after accounting for maternal factors and development of hypertensive disorders of pregnancy and gestational diabetes mellitus, uterine artery pulsatility index, and placental growth factor.

CONCLUSION

The findings of our study indicate a weak but significant association between maternal cardiovascular indices with placental perfusion at mid-gestation and birthweight. Our data would not support routine maternal cardiovascular assessment for predicting birthweight.

First-trimester maternal tryptophan metabolites, utero-placental (vascular)development and hypertensive disorders of pregnancy: The Rotterdam periconceptional cohort

BACKGROUND

Hypertensive disorders of pregnancy (HDP) are a significant cause of maternal and perinatal mortality and morbidity. Knowledge on the placenta-related pathophysiology of HDP is increasing. Since maternal tryptophan metabolites are involved in placentation, we investigated associations between first-trimester tryptophan metabolites and utero-placental (vascular) development, and the occurrence of HDP.

METHODS

911 women were included from a prospective tertiary hospital cohort. Serum tryptophan metabolites were determined at 8.1 ± 1.4 weeks gestation. Placental volume (PV) and utero-placental vascular volume (uPVV) were determined at 7, 9 and 11 weeks gestation. HDP, including hypertension in early pregnancy, gestational hypertension, and preeclampsia, were retrieved from medical records. Associations with PV- and uPVV-trajectories were assessed using mixed models, and HDP risks were estimated by logistic regression models, adjusted for confounders. A mediation analysis was performed to evaluate whether blood pressure was a mediator in the associations with utero-placental (vascular) development.

RESULTS

A negative association between kynurenine and PV-trajectories was found (β = -0.129, 95%CI = -0.220 to -0.039), which was not mediated by blood pressure. No significant associations between other tryptophan metabolites and PV- and uPVV-trajectories were observed. Higher 5-hydroxytryptophan was associated with hypertension in early pregnancy (OR = 1.405, 95%CI = 1.210-1.681), and with an increased risk of preeclampsia in these women. No associations between tryptophan metabolites and other HDP were found.

CONCLUSIONS

Higher first-trimester kynurenine concentrations were associated with impaired utero-placental (vascular) development. Higher first-trimester 5-hydroxytryptophan concentrations were associated with early pregnancy hypertension, and an increased risk of preeclampsia, indicating its clinical potential as biomarker for future prediction, prevention and treatment of HDP.

Pregnancy-specific beta-1-glycoprotein 1-enriched exosomes are involved in the regulation of vascular endothelial cell function during pregnancy

INTRODUCTION

Pregnancy is a dynamic time period associated with significant physiological changes in the cardiovascular system. It is well known that during pregnancy, the placenta secretes a variety of molecular signals, including exosomes, into the maternal circulation to adapt to increased blood volume and maintain blood pressure at normotensive levels.

METHODS

In the present study, we compared the effects of exosomes derived from the peripheral blood serum of nonpregnant women (NP-Exo) and pregnant women with uncomplicated pregnancy (P-Exo) on endothelial cell function. We also analyzed the proteomic profiles of these two groups of exosomes and the molecular mechanisms underlying the effect of exosome cargoes on vascular endothelial cell function.

RESULTS

We found that P-Exo were positively involved in regulating the function of human umbilical vein endothelial cell (HUVEC) and promoting the release of nitric oxide (NO). Furthermore, we revealed that trophoblast-derived pregnancy-specific beta-1-glycoprotein 1 (PSG1)-enriched exosomes treatment induced the promotion of HUVEC proliferation and migration as well as the release of NO. In addition, we found that P-Exo maintained blood pressure at normal levels in mice.

DISCUSSION

These results suggested that PSG1-enriched exosomes derived from maternal peripheral blood regulate the function of vascular endothelial cells and play an important role in maintaining maternal blood pressure during pregnancy.