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Chronic Hypertension in Pregnancy

Chronic hypertension in pregnancy is defined as a blood pressure greater than or equal to 140/90 prior to pregnancy, before the 20^th week or after six weeks postpartum. With chronic hypertension, maternal outcome and fetal outcome is good in those cases with moderate hypertension. They have an increased risk for superimposed preeclampsia and abruption, and that the fetus is at increased risk for intrauterine growth retardation and fetal demise. If the hypertension is accompanied by an elevated serum creatinine and in most studies this is a creatinine greater than 1.5, the risk to the mother and the fetus substantially increase, so if you have compromised renal function.

In terms of hypertensive pharmacologic therapy, the general principal is to use the safest drug, the least number of drugs and the lowest possible dose, so I usually do step therapy, try to put them just on one medication, the lowest possible, gradually up it and then add a second agent if I have to. There really isn’t any proven benefit of starting antihypertensive therapy in terms of the pregnancy unless blood pressures are in the 150/100 range. That refers to preventing preeclampsia or poor outcome, however, you could say that since JNC6 really recommends blood pressures to be 130/80 to 140/90.

All the drugs you will need to use in managing in your chronic hypertensives on an outpatient basis and it gives you the total mg per day, the low end, the highest dose and the frequency. One thing to remember, when you are combining drugs, you kind of like to keep the patient on the same schedule, if they are taking twice a day, you don’t want to add something three times a day and most of these drugs most often you have to give them is twice a day, no you really don’t need to have anybody on three times a day medication, they just won’t be compliant with that. Once you have gotten their blood pressure controlled, you are also going to be following the fetus and the general recommendation in these pregnancies.

The problem with chronic hypertension really is distinguishing superimposed preeclampsia, it’s very hard to tell in someone who has significant chronic hypertension and maybe is not well controlled, what does their blood pressure elevation do to their chronic disease and should you increase in the medication, and if they have proteinuria to start with, is it just worsening of the proteinuria during pregnancy, this is a patient I think who is a clear cut example of superimposed preeclampsia, hopefully you won’t see these patient’s too often, but again, it’s an example of how somebody who doesn’t seem maybe that sick at first can deteriorate very quickly. This patient presented at 29 ½ weeks, she had a history of chronic hypertension and she had been pretty well controlled on Procardia during her pregnancy. She had no prior history of preeclampsia.

Renal Disease in Pregnancy. It is important to remember some basic physiologic and anatomic changes that occur during pregnancy because it does affect our management. Basically, kidney weight is significantly increased in pregnancy and you will see ureteral and caliceal dilatation usually right will be greater than left. This really needs to the physiologic hydronephrosis in pregnancy, so it can be hard on a renal ultrasound to tell what is significant in terms of hydronephrosis and what isn’t. There is a rise in renal plasma flow and GFR, so the normal serum creatinine is really about 0.5 at the time of the third trimester. There is certainly a net sodium retention which is important for plasma volume expansion.

We are going to talk primarily about urinary tract infections, renal calculi, chronic renal disease and I will spend some time talking about hemodialysis and renal transplant. A very common problem is asymptomatic bacteria, and usually that is greater than 100,000 colonies on a clean catch, but if you send a cath urine, you should realize greater than 100 colonies per ml is significant, you shouldn’t have anything growing out on a cath urinalysis, if it was obtained properly and you should treat that.