Contributions of blood pressure to proteinuria and renal function in the puerperium

Increasing evidence indicates that hypertension in pregnancy plays a key role in cardiovascular disease. However, the correlation between blood pressure (BP) and proteinuria as well as renal function in the puerperium has not been established.

We evaluated the estimated glomerular filtration rate (eGFR) and 24-h urine total protein excretion (TPE) during the second postpartum week in 852 pregnant women with normal BPs and 114 pre-eclamptic women with BPs > or =140/90 mmHg. The 852 pregnant women with normal BPs were divided into two groups based on the mean arterial pressure (MAP): 684 subjects with an MAP<90 mmHg and 168 subjects with an MAP> or =90 mmHg.

The eGFR was significantly decreased in pre-eclamptic women (112+/-41 ml/min/1.73 m(2)) compared with healthy women with an MAP<90 mmHg (131+/-35 ml/min/1.73 m(2), p<0.01) and an MAP> or =90 mmHg (128+/-34 ml/min/1.73 m(2), p<0.01), while the TPE was significantly increased compared with healthy women with an MAP<90 mmHg and an MAP> or =90 mmHg (1790+/-1422 vs 124+/-148 and 255+/-427 mg/24 h, respectively; p<0.001). Although the eGFR did not reveal a difference between the two groups of healthy women (131+/-35 vs 128+/-34 ml/min/1.73 m(2), p>0.05), the TPE was significantly higher in subjects with an MAP> or =90 mmHg than in subjects with an MAP<90 mmHg (255+/-427 vs 124+/-148 mg, p=0.004).

Pre-eclampsia induces significant renal injury characterized by an elevation of TPE and a reduction in GFR. BP is closely related to urinary protein excretion, even in healthy women (BP <140/90 mmHg) in the puerperium.