Maternal haemodynamic and haemorrheologic considerations in fetal I.U.G.R

Maternal cardiac function in fetal growth restriction

OBJECTIVE

To assess the maternal central haemodynamics in normotensive women with pregnancies complicated by severe fetal growth restriction (FGR).

DESIGN

Cross-sectional study.

SETTING

A tertiary referral fetal medicine unit.

POPULATION

The study groups comprised 107 women with normal singleton pregnancies and 20 with singleton pregnancies complicated by FGR at 25-37 weeks. In the latter group, assessment was carried out within 10 days prior to their delivery. All the women were normotensive, without any medical problems.

METHODS

Two-dimensional and M-mode echocardiography of the left ventricle.

MAIN OUTCOME MEASURES

Maternal left ventricular systolic and diastolic function.

RESULTS

In the FGR group, compared with the normal group, there was increased total vascular resistance (TVR), reduced systolic function characterised by lower cardiac output, stroke volume, heart rate, ejection time and septal and lateral long-axis shortening. Mean arterial pressure (MAP) was not significantly different between the groups.

CONCLUSIONS

Severe FGR is associated with reduced maternal systolic function and increased TVR but no change in MAP. TVR may be a useful tool in the classification and management of FGR. The findings suggest that in FGR, there is increased blood viscosity due to lack of intravascular space expansion.

Pregnancy at high altitude: a hyperviscosity state

BACKGROUND

Pregnancy at high altitude has been associated with intrauterine growth restriction and preeclampsia. These conditions, at sea level, have been linked to increased hematocrit and blood viscosity. The aim of this study was to investigate the effect of high altitude on maternal hemorheology.

METHODS

This was a cross-sectional study. We examined 94 pregnant women at 10-38 weeks of gestation resident at high altitude (4370 m above sea level) and 75 at sea level, and 24 and 17 nonpregnant women at each altitude, respectively. Blood and plasma viscosity, hematocrit, plasma fibrinogen, albumin and total protein concentrations were determined in blood samples obtained after an overnight period of fasting.

RESULTS

Pregnancy at high altitude, compared to sea level, is characterized by higher hematocrit, blood viscosity (at high shear rate), plasma viscosity, total protein and fibrinogen concentrations (25%, 38%, 7%, 13.3% and 25%, respectively) and 6% lower albumin concentration. Nonpregnant women at high altitude, compared to sea level, had higher hematocrits, blood viscosity, plasma viscosity, total protein and fibrinogen concentrations (25%, 55%, 18%, 26% and 98%, respectively) and 13% lower albumin concentration.

CONCLUSION

Pregnancy at high altitude compared to sea level is characterized by increased blood viscosity as a result of increased hematocrit and plasma viscosity.