Acute kidney injury in pregnancy-specific disorders

The incidence of acute kidney injury in pregnancy (P-AKI) has declined significantly over the last three decades in developing countries. However, it is still associated with significant fetomaternal mortality and morbidity. The diagnosis of P-AKI is based on the serum creatinine increase. The usual formulas for estimating glomerular filtration rate (GFR) are not validated in this population. The incidence of P-AKI with respect to total AKI cases has decreased in the last three decades from 25% in 1980s to 9% in 2000s at our centre. During the first trimester of gestation, AKI develops most often due to septic abortion or hyperemesis gravidarum. Septic abortion related AKI with respect to total AKI decreased from 9% to 5% in our study. Prevention of unwanted pregnancy and avoidance of septic abortion are keys to eliminate abortion associated AKI in early pregnancy. However, we have not seen AKI on account of hyperemesis gravidarum over a period of 33 years at our center. In the third trimester, the differential diagnosis of AKI in association with pregnancy specific conditions namely preeclampsia/HELLP syndrome, acute fatty liver of pregnancy and thrombotic microangiopathies of pregnancy (P-TMA) is more challenging, because these 3 conditions share several clinical features of thrombotic microangiopathy which makes the diagnosis very difficult on clinical grounds. It is imperative to distinguish these conditions to make appropriate therapeutic decisions. Typically, AFLP and HELLP syndrome improve after delivery of the fetus, whereas plasma exchange is the first-line treatment for pregnancy associated thrombotic microangioathies (P-TMA). We observed that preclampsia/eclampsia is the most common cause of AKI in late third trimester and postpartum periods followed by puerperal sepsis and postpartum hemorrhage. Pregnancy-associated thrombotic microangiopathies (aHUS/TTP) and AFLP are rare causes of AKI during pregnancy in developing countries.