Pregnancy and the Kidney

Pregnancy and the Kidney

The Nobel Laureate Joseph Murray provided the first report of pregnancy in a transplant recipient (1). Since that time, over 16,000 pregnancies have been documented in the world literature (2). Many more pregnancies have clearly occurred, now that pregnancy after transplantation is commonplace and is rarely reported. The data about pregnancy in transplant recipients come from case reports and registry reports, but these sources underrepresent the population of transplant recipients who have become pregnant (2).

About 5 percent of pregnancies suffer complications from abnormal placental development. The process of placentation begins when blastocysts adhere to the uterine endometrium, forming a lineage of epithelial cells termed the invasive extravillous cytotrophoblast, which then invades the uterine wall to create the decidua, transforming the spiral arteries into a low-resistance uteroplacental circulation.

Pre-eclampsia is a systemic syndrome occurring in the second half of pregnancy, with cardinal manifestations of hypertension and proteinuria. Pre-eclampsia is one of the most common glomerular diseases in the world; it affects approximately 3–5 percent of all pregnancies. Although careful obstetric management—including antihypertensive medications and seizure prophylaxis with intravenous magnesium—is important for the treatment of pre-eclampsia, delivery of the neonate and placenta remains the only definitive treatment.

During pregnancy, the development of acute renal failure is especially daunting because two lives are involved and at risk. The outcomes of acute kidney injury (AKI), as in other settings, can be quite poor, with significant morbidity and mortality rates of 20–30 percent.

Healthy kidneys—healthy pregnancy

A healthy pregnancy—a baby born at term, with minimal untoward physical consequences to the mother—is the ideal outcome and indeed, when it occurs, is nothing short of a miracle.