Kidney Problems During Pregnancy

In short: Kidney problems in pregnancy may be long-standing, as with diabetes, immune disease or polycystic kidneys, or new, as with pre-eclampsia and severe infection. They raise the risk of high blood pressure, pre-eclampsia, anaemia, slow growth of the baby and preterm birth. Care is shared between the obstetrician and the kidney specialist, with tests of kidney function and urine, and blood pressure kept below 135/85.

Kidney problems during pregnancy are complex and can make the pregnancy high-risk due to the physiological changes that increase the demands on the kidneys.

If kidney problems during pregnancy are not properly managed, they can lead to serious complications for both the mother and the fetus.

What physiological changes occur in kidney function during pregnancy?

• Increased blood plasma volume flow to the kidneys
• Increased glomerular filtration rate
• Decreased blood urea and creatinine levels
• Slight dilation of the renal pelvis

Types of kidney problems during pregnancy:

• Chronic problems (pre-existing before pregnancy)
• New problems that develop during pregnancy

What are the causes of chronic kidney problems?

• Diabetes
• Autoimmune diseases such as lupus
• Polycystic kidney disease
• Renal vasculitis
• Vesicoureteric reflux (urine flowing back from the bladder up to the kidneys), which can cause kidney scarring

What are the causes of kidney problems during pregnancy?

• Preeclampsia and high blood pressure during pregnancy
• Kidney infection (pyelonephritis) spreading up from the bladder, or severe infection in the bloodstream (sepsis)
• Bleeding leading to kidney tissue death
• Acute fatty liver disease during pregnancy

What are the risks of kidney problems for mothers during pregnancy?

• High blood pressure and preeclampsia
• Fluid buildup in the lungs
• Fluid retention
• Anemia due to erythropoietin deficiency
• The need for dialysis
• Recurrent kidney/urinary tract infections during pregnancy

What are the risks of maternal kidney problems to the fetus during pregnancy?

• Intrauterine growth restriction
• Premature birth
• Low amniotic fluid
• Intrauterine fetal death

What tests are performed to check/monitor kidney function during pregnancy?

• Kidney function blood test
• Urinalysis to check for blood or protein

Urine culture to detect infection (even without symptoms) and a urine protein:creatinine ratio to measure the amount of protein

• Blood pressure monitoring
• Kidney ultrasound

Should fetal growth and measurements be monitored regularly during pregnancy when the mother has kidney problems?

Yes

What should the blood pressure of a pregnant woman with kidney problems be?

Below 135/85

Because kidney disease raises the risk of pre-eclampsia, women with kidney problems are usually advised to take low-dose aspirin (75–150 mg daily) from 12 weeks of pregnancy until birth. Some blood pressure medicines commonly used for kidney disease (ACE inhibitors such as enalapril, and ARBs such as losartan) are not safe in pregnancy and should be changed, ideally before conception or as soon as pregnancy is confirmed. Never stop any medicine on your own; discuss this with your doctor.

It should be noted that the monitoring of a pregnant woman with kidney problems should be a joint effort between an obstetrician and a nephrologist.

Ideally, a woman with known kidney disease should see her doctors before trying to conceive, so that blood pressure, kidney function and medicines can be optimised and the best time for pregnancy can be planned.

Dr Najeeb Layyous F.R.C.O.G

Consultant Obstetrician, Gynecologist and Infertility Specialist