A woman’s body goes through enormous changes during pregnancy and the kidneys are one among the many organs that change structurally and functionally. The Kidneys enlarge by 1 cm, the blood flow through kidneys increase by 50%, the renal pelvis and the urethra (especially the right one) is dilated and the kidneys retain salt and water causing weight gain during pregnancy. The blood pressure decreases in the initial half of pregnancy and returns to the pre pregnancy levels in the second half. The Creatinine level* drops as the filtering function of the kidneys increase by 30%. These Physiological (normal) changes happen to every pregnant woman.
*Creatinine level from 0.5 to 1.1 mg are considered healthy in adult females.
However, certain Pathological (abnormal) changes in the kidneys that happen especially during pregnancy causes disease; such as
Urinary Tract Infection (UTI) – the commonest kidney problem during gestation shows no symptoms and can be diagnosed only through routine urine cultures. Pregnant women have 40% higher chances of this infection progressing to affect the kidneys (pyelonephritis) and the bladder (cystitis). Screening cultures are done and treated by obstetricians who prescribe antibiotics for 5- 14 days and if necessary, throughout pregnancy.
Gestational Hypertension is the onset of blood pressure in the second half of pregnancy and is treated with medicines if BP levels are above 150/100. This resolves after delivery.
Pre-eclampsia is when women have, along with high blood pressure, swelling and increase in urine protein. It causes decreased nutrition supply and blood flow to the baby causing growth restriction. The disorder affects the liver and blood clotting in the mother and can even lead to the mother’s death if left untreated. This needs aggressive management.
Eclampsia is when women with pre-eclampsia are affected by seizure or fits. This is an emergency situation and needs immediate delivery to save the mother.
Acute Kidney Injury (AKI)
This is a condition when the kidneys fail within days to weeks. It is evidenced by swelling due to retention of water and salt and an increase in the blood urea and creatinine levels. The ‘pregnancy specific’ causes of AKI are:
• Kidney infection – acute pyelonephritis
• A platelet disorder called HELLP (Hemolysis with Elevated Liver enzymes and Low Platelet)
• Acute Fatty Liver – a liver disease that happens in the third trimester of pregnancy.
• Renal Cortical Necrosis – an injury where parts of the kidney are totally damaged. This occurs in pregnancy when there is severe bleeding during delivery due to abnormalities in the placenta etc.
Pregnancy’s effect on Renal disease
Of the women with renal disease who get pregnant, 50% of them have increase in the urine protein and 25% have increase in blood pressure which can be a new onset BP or worsening of pre existing BP. Kidney function can worsen during pregnancy in patients with renal disease. Women with baseline creatinine level higher than 1.g mg/dl, Urine protein higher than 3 g/day are at a higher risk. Women with Lupus nephritis need to be in remission and women with reflux nephropathy are at a higher risk for UTI.
Renal disease’s effect on pregnancy
Kidney diseases put the pregnant mothers at risk of hypertension, pre-eclampsia and even death. It can put the baby at risk of growth restriction, pre term birth and foetal loss. It contributes to increase in caesarean delivery.
Preparation and Precautions for Pregnancy
Dr. K. Abirami says, “It is wise to visit a nephrologist before planning your pregnancy as certain measures need to be taken to prepare your body for the upcoming change. Blood pressure should be brought under control and creatinine levels should be less than 1.5 mg/dl to get pregnant. We examine the patient and suggest folic acid and other vitamins and alter or stop certain medications according to the patient’s condition”.
• Prenatal visits in the first and second trimester should happen fortnightly or monthly according to the nature of the condition; and weekly in the third trimester.
• Monthly/ bi – monthly monitoring of maternal renal functions.
• Foetal surveillance through ultrasound and foetal heart rate monitoring to assess foetal growth and well being.
• Close monitoring for detection and treatment for asymptomatic UTI, pre-eclampsia and maternal hypertension (deterioration of these conditions might cause growth restriction, foetal distress etc. In which case pre term intervention will be necessary).
• Caesarean delivery is advised, if labour does not occur within the estimated date of confinement.
The chances for women on dialysis to get pregnant are slim, 0.3 to 1.5 %. However, if you do get pregnant, there is good news. With advancement in dialysis methods such as nocturnal daily dialysis program, successful pregnancies have risen to 80% which was previously only 50%. Along with more dialysis, your nephrologist will recommend increased protein intake, higher doses of Iron, Erhytropoietin and calcium.
Pregnancy after Renal Transplant, studies show, does not adversely affect the kidneys for even up to 10 years post transplant. But the probability of pre-eclampsia, intrauterine growth restriction and pre term labour will be the same as before the transplant. In such a case, women can plan their pregnancy
• 1 or 2 years after renal transplantation with stable graft function and minimal proteinuria
• Well controlled Blood Pressure
• No episodes of rejection or major infection.
Find out from your Nephrologist about
• Modifying immunosuppressives
• Switching Sirolimus and mycophenolate to other drugs
• Stopping blood pressure medicines like ACE inhibitors and ARBS.
Article by Dr. K.Abirami, Nephrologist, Kauvery Hospital, Salem.