Maternal outcomes
Of the 31 patients with PR-AKI,13 were in the CRRT group, including five cases of AFLP (38%) and three cases of septic or hemorrhagic shock (23%). The remaining 18 patients received non-replacement therapy (39%), including seven cases of PE/E (39%), three cases of AFLP (16%), and three cases of septic shock (16%), as shown in Figure 1. In the CRRT group, four patients (31%) had complete recovery of renal function, three (23%) had partial recovery of renal function but ended substitution therapy, and four (31%) died. In the group with complete recovery of renal function, the average CRRT included six treatment times, and the average cumulative treatment duration was 61.54 hours. In the group with partial recovery of renal function, the average CRRT included five treatment times, and the average cumulative treatment duration was 51.5 hours. Compared with the partially recovered renal function group, the complete recovery group had more CRRT treatment times, longer cumulative treatment durations, and better maternal and infant outcomes.
Among the 18 cases in the non-CRRT group, 13 had complete renal function recovery, one received renal replacement therapy, one did not recover renal function and delivered a stillbirth, and three died. In the CRRT group, WBC, neutrophil %, NLR, AST, AST, serum uric acid, and SCr were significantly lower than before CRRT treatments (P<0.05). Lactic acid, BUN, albumin, Na+, and K+ were lower than before CRRT treatments, but with no statistical difference, as shown in Table 2.
Among the 18 cases in the non-CRRT group, 13 had complete renal function recovery, one received renal replacement therapy, one did not recover renal function and delivered a stillbirth, and three died. In the CRRT group, WBC, neutrophil %, NLR, AST, AST, serum uric acid, and SCr were significantly lower than before CRRT treatments (P<0.05). Lactic acid, BUN, albumin, Na+, and K+ were lower than before CRRT treatments, but with no statistical difference, as shown in Table 2.
Table 2 Comparison of laboratory examinations before and after CRRT treatment
|
Before treatment
|
After treatment
|
T/Z value
|
P-value
|
WBC (×109/L)
|
22.10±6.27
|
9.70±7.04
|
4.009
|
0.002
|
N %
|
91.17±4.64
|
61.98±20.31
|
4.987
|
0.000
|
NLR
|
3.92 (4.50)
|
4.80 (7.93)
|
-3.667
|
0.000
|
BUN (mmol/L)
|
16.41±11.45
|
11.65±9.38
|
1.233
|
0.241
|
SCr (μmol/L)
|
363.25±202.99
|
177.85±149.85
|
4.061
|
0.002
|
Uric acid (mmol/L)
|
522.21±133.05
|
247.05±136.85
|
4.940
|
0.000
|
ALT (U/L)
|
70.00 (89.00)
|
29.00 (31.00)
|
-2.515
|
0.012
|
AST (U/L)
|
96.00 (79.50)
|
32.00 (67.00)
|
-2.130
|
0.033
|
ALB (g/L)
|
29.93±11.87
|
31.11±8.01
|
-1.725
|
0.110
|
Na+ (mmol/L)
|
133.38±7.41
|
139.29±5.86
|
-2.284
|
0.041
|
K+ (mmol/L)
|
4.52±0.90
|
4.01±0.54
|
2.115
|
0.056
|
Lactic acid (mmol/L)
|
4.80 (7.93)
|
1.85 (5.68)
|
-1.421
|
0.155
|
PLT (×109/L)
|
85.54±52.06
|
206.08±111.09
|
-3.154
|
0.008
|
Fetal outcomes
Fetal outcomes are summarized in Table 3. The 31 patients with PR-AKI delivered 35 newborns, including 25 parturients (83.33%) with a single pregnancy, 5 parturients (16.67%) with a twin pregnancy, and 26 cesarean sections (83.9%). Among the newborns, eight (22.86%) were full-term, 17 (48.57%) were premature, and one (2.86%) was post-term. Five died, with a mortality rate of 14.26%, and 22 were transferred to NICU (62.86%). Seven newborns had a birth weight ≥2500 g (20.00%), 10 had a birth weight ≥1500g but <2500 g (28.57%), and eight had a birth weight <1500 g (22.86%). Among the three groups, the best pregnancy outcomes were in the puerperium group, and the worst were in the second trimester group (P<0.05). These results are consistent with those reported in the literature [2].
Table 3 Fetal outcomes
Outcomes
|
Number
|
Second trimester
|
Third trimester
|
Puerperium
|
Infants (%)
|
35
|
6 (17.14)
|
20 (57.14)
|
9 (25.71)
|
Term infants (%)
|
8 (22.86)
|
0
|
4 (50.00)
|
4 (50.00)
|
Pre-term infants (%)
|
17 (48.57)
|
3 (17.65)
|
10 (58.82)
|
4 (23.53)
|
Post-term infants (%)
|
1 (2.86)
|
0
|
0
|
1 (100.00)
|
Stillbirths (%)
|
5 (14.29)
|
3 (60.00)
|
2 (40.00)
|
0
|
Severe asphyxia (%)
|
5 (14.29)
|
1 (20.00)
|
1 (20.00)
|
3 (60.00)
|
Birth weight, g
≥2500 (%)
≥1500 but <2500 (%)
<1500 (%)
|
7 (20.00)
10 (28.57)
8 (22.86)
|
0
0
3 (37.50)
|
4 (57.14)
9 (90.00)
5 (62.50)
|
3 (42.86)
1 (10.00)
0
|
Apgar scores
1 minute
5 minutes
10 minutes
|
6.48±3.24
7.85±2.63
9.00±2.08
|
5.53±1.16
6.67±1.53
6.67±1.53
|
7.00±3.31
8.06±2.90
9.19±2.58
|
5.50±3.73
7.83±2.32
9.67±0.82
|
Transfer to NICU (%)
|
22 (62.86)
|
3 (13.64)
|
15 (68.18)
|
4 (18.19)
|
Loss to follow-up (%)
|
3 (8.57)
|
0
|
0
|
3 (100.00)
|
Characteristics of the CRRT group
A total of 13 patients with PR-AKI received CRRT treatment. The mean timing of the CRRT intervention was 1.92±1.12 days after admission, the mean number of treatments was 7.09±7.39, and the mean cumulative treatment time was 63.31±45.43 hours. The main causes were AFLP in five cases (38.46%), infectious or hemorrhagic shock in three cases (23.08%), severe preeclampsia in one case (7.69%), and postpartum hemorrhage in one case (7.69%); two cases were A/C. Among the 13 patients was one with AKI stage 1, where the primary disease was chronic glomerulonephritis, who received CRRT treatments 29 times and long-term renal replacement therapy after delivery. The infant had a poor prognosis due to low birth weight with severe asphyxia. In the one case of AKI stage 2, with a main cause of Alphard with twin pregnancy, CRRT treatments were more frequent, and the commencement time of CRRT was earlier. As expected, the prognosis was good, and the newborns survived. In the 11 cases of AKI stage 3, three partially recovered renal function, two progressed to end-stage renal disease, and four died; three newborns did not survive.
Analysis of adverse pregnancy outcomes and risk factors in PR-AKI patients
Among the 31 patients with PR-AKI, 25 (80.6%) had poor fetal outcomes, including five stillbirths, five cases of neonatal asphyxia, 18 premature births, 10 low birth weight infants, and eight deficient birth weight infants. Six patients had good fetal outcomes. The gestational age, platelet count, and hemoglobin of patients with good fetal outcomes were significantly higher than those with poor fetal outcomes (all P<0.05). BUN and uric acid were significantly lower than those with poor fetal outcomes (all P<0.05). No significant difference existed between the age, the number of pregnancies and deliveries, NLR, ALT, AST, albumin, SCr, and the composition ratio of CKD patients (all P>0.05), as shown in Table 4.
Table 4 Comparison of PR-AKI patients with different fetal outcomes
|
Good outcomes
n=6
|
Poor outcomes
n=25
|
Age (x2±s, years)
|
28.17±2.64
|
29.4±5.40
|
Gestational weeks (x2±s, weeks)
|
39.26±1.53①
|
31.62±5.50
|
Number of pregnancies (x2±s, times)
|
2.00±1.26
|
1.88±1.27
|
Number of deliveries (x2±s, times)
|
1.33±0.52
|
1.20±0.58
|
NLR (x2±s)
|
12.15±4.19
|
27.07±20.70
|
Platelet count (x2±s, ×109/L)
|
217.13±122.87①
|
90.24±84.88
|
Hemoglobin (x2±s, g/L)
|
94.19±13.21①
|
74.48±20.78
|
ALT (x2±s, U/L)
|
34.22 (153.10)
|
68.00 (116.00)
|
AST (x2±s, U/L)
|
44.00 (313.26)
|
102.10 (165.50)
|
Albumin (x2±s, g/L)
|
33.75±1.47
|
27.99±12.66
|
BUN (x2±s, mmol/L)
|
11.87±4.28①
|
19.47±10.98
|
SCr (x2±s, μmol/L)
|
178.94±137.46
|
294.02±211.54
|
Uric acid (x2±s, μmol/L)
|
262.41±167.00①
|
586.87±144.52
|
CKD (n, %)
|
2 (33.33%)
|
1 (4.00%)
|
AKI Stage (n, %)
Stage 1
Stage 2
Stage 3
|
1 (16.67%)
1 (16.67%)
4 (66.67%)
|
11 (44.00%)
3 (12.00%)
11 (44.00%)
|
① Compared with poor pregnancy outcomes: P<0.01.
Logistic regression analysis was performed on these factors. Gestational age (OR=0.456, P=0.023), platelet count (OR=0.989, P=0.02), hemoglobin (OR=1.017, P=0.022), and uric acid (OR=1.017, P=0.022) were risk factors for poor fetal outcomes in PR-AKI patients (Table 5). Age, number of pregnancies, parity, NLR, ALT, AST, plasma, albumin, SCr, and CKD did not affect pregnancy outcomes (P>0.05).
Table 5 Logistic regression analysis of risk factors for adverse fetal outcomes
Variables
|
Regression coefficients
|
Standard error
|
Wald
|
P-value
|
OR
|
Gestational weeks
|
-0.786
|
0.345
|
5.204
|
0.023
|
0.456
|
PLT
|
-0.011
|
0.005
|
5.421
|
0.020
|
0.989
|
HB
|
-0.050
|
0.027
|
3.573
|
0.059
|
0.951
|
Uric acid
|
0.017
|
0.007
|
5.241
|
0.022
|
1.017
|