Outcome of Pregnancy in an Oxford-Cardiff Cohort of Women with Previous Bacteriuria

To investigate the influence of asymptomatic bacteriuria inchildhood on subsequent pregnancy, we reviewed the outcome of139 pregnancies in 88 women who were first identified duringa programme of screening schoolgirls for asymptomatic bacteriuriacarried out between 1970–1972 [1]. Data were analysedfor the following groups: 50 pregnancies in 28 women with knownrenal scars (group 1); 16 pregnancies in 14 women with normalkidneys and reflux (group 2); 73 pregnancies in 46 women withnormal urinary tracts (group 3); 139 healthy controls. Women in group 1 had a 3.3-fold increased relative risk of hypertension(p < 0.01) and a 7.6-fold increased risk of pre-eclampsia(p< 0.05) compared to controls, and a higher rate of obstetricinterventions, including emergency caesarean section. Womenin groups 2 and 3 appeared to carry a slightly increased riskof hypertension during the last trimester (RR = 1.8) but therewere no significant differences in this or the incidence ofpre-eclampsia or mode of delivery. Bacteriuria was more prevalentin all index groups compared to controls (37 per cent vs. 8per cent, p < 0.01) and included four cases of acute pyelonephritisin the study group. Fetal outcome was satisfactory in all cases.These results suggest that women with renal scars are at riskof hypertension and pre-eclampsia during pregnancy but thatmodern obstetric care minimizes these risks.     

Effects of chronic sympatho-inhibition on reflex control of renal blood flow and plasma renin activity in renovascular hypertension

Background and purpose:

We determined if chronic sympatho-inhibition with rilmenidine has functional significance for the kidney by altering responses of renal blood flow (RBF) and plasma renin activity (PRA) to stress and acute hypotension in rabbits with renovascular hypertension.

Experimental approach:

RBF to each kidney and renal sympathetic nerve activity (RSNA) to the left kidney were measured in rabbits in which a renal artery clip induced hypertension (2K1C) and in sham-operated rabbits. After 2 weeks, a subcutaneous minipump was implanted to deliver rilmenidine (2.5 mg·kg⁻¹·day⁻¹) to 2K1C rabbits for 3 weeks.

Key results:

After 5 weeks of renal artery stenosis, mean arterial pressure (MAP) was 23% higher and PRA 3-fold greater than in sham-operated rabbits. Blood flow and renal vascular conductance in the stenosed kidney were lower (−75% and −80%) compared with sham, and higher in the non-clipped kidney (68% and 39%). Responses of RBF and PRA to hypotension were similar in 2K1C and sham rabbits. Airjet stress evoked a greater increase in MAP in 2K1C rabbits than sham controls. Chronic rilmenidine normalized MAP, reduced RSNA and PRA, and did not reduce RBF in the stenosed kidney. Responses of RBF (clipped and non-clipped kidney), RSNA and PRA to hypotension and airjet were little affected by rilmenidine.

Conclusions and implications:

Our observations suggest that chronic sympatho-inhibition is an effective antihypertensive therapy in renovascular hypertension. It normalizes MAP and reduces basal PRA without compromising blood flow in the stenosed kidney or altering responses of MAP, haemodynamics and PRA to acute hypotension and stress.