Clinical predictors in early pregnancy for adverse pregnancy outcomes in women complicated with chronic nephropathy

Abstract

Objective To investigate clinical predictors in early pregnancy for adverse pregnancy outcomes in women complicated with chronic nephropathy. Methods One hundred and eighty-four pregnancies complicated with chronic nephropathy who delivered between January, 2005 and January, 2014 in Peking University First Hospital were retrospectively analyzed. Two hundred pregnant women without chronic nephropathy were selected as the control group. Pregnancy outcomes were compared between the two groups. Relationships between clinical predictors in early pregnancy [age, history of kidney disease, drugs used before pregnancy (in three months), results of renal biopsy, blood pressure, serum creatinine, urea nitrogen, 24 h urinary protein, estimated glomerular filtration rate, stage of chronic nephropathy] and adverse pregnancy outcomes [maternal mortality; pregnancy complicated by severe preeclampsia; renal function decline, early preterm birth, very low birth weight infants, fetal loss after 20 weeks of pregnancy] were assessed by logistic regression analysis. T-test, Chi-square test and multivariate regressions were used for statistical analysis. Results There were 174 and 197 livebirths in the study and the control groups, respectively. The most popular type of chronic nephropathy in pregnant women was IgA nephropathy (38.6%, 71/184). Compared with the control group, the risk of premature labor [9.8%(17/174) vs 3.0%(6/197), χ2=7.184], low birth weight infants[18.4%(32/174) vs 7.1%(14/197), χ2=9.813], very low birth weight infants [5.7%(10/174) vs 1.5%(3/197), χ2=4.536], fetal loss after 20 weeks of pregnancy [5.7%(10/184) vs 1.5%(3/200), χ2=4.536] and severe preeclampsia [17.9%(33/184) vs 1.5%(3/200), χ2=33.544] increased significantly in the study group (all P<0.05). Twenty-four-hour urinary protein content (OR=1.84, 95%CI: 1.36-2.50, P=0.001) and mean arterial pressure (OR=1.04, 95%CI: 1.00-1.07, P=0.027) in early pregnancy were risk factors for adverse pregnancy outcomes. The risk of renal function decline increased significantly in patients with higher stages of chronic nephropathy in early pregnancy (OR=6.50, 95%CI: 3.34-8.21, P<0.01). Mother complicated by preeclampsia during pregnancy was an independent risk factor (OR=11.10, 95%CI: 4.48-27.20, P<0.01). Compared with women whose 24 h urinary protein content less than 1g in early pregnancy (122 livebirths within 126 cases), the risk of premature labor [17.3%(9/52) vs 6.6%(8/122), χ2=4.780], increased significantly in women whose 24 h urinary protein content were more than or equal to 1 g in early pregnancy (52 livebirths within 58 cases) (P<0.05). Conclusions Elevated urinary protein level and mean arterial pressure in early pregnancy were risk factors of adverse pregnancy outcomes. The risk of renal function decline increased in patients with higher stages of chronic nephropathy in early pregnancy. Mother complicated by preeclampsia during pregnancy was an independent risk factor for poor prognosis of the fetus. Key words: Pregnancy outcomes; Prognosis; Pregnancy complications; Renal insufficiency, chronic; Pregnancy trimester, first