Study Population and Baseline values
During the enrollment period, the consecutive medical records of 511 pregnant women at our center were reviewed. Among them, 236 patients were excluded due to other reasons of liver failure (Fig. 1) and 55 were dianosed with AFLP and enrolled into group A. 220 patients without AFLP and other liver diseases were selected as control and assigned to group B. All patients in group A were were further assigned into group A1 if the intrauterine balloon was used to prevented the postpartum hemorrhage or group A2 if not. The patients who were screened and enrolled into the different study groups are shown in Fig. 1.
The clinical characteristics of patients at delivery in each group are shown in Table 1. When compared to patients without AFLP (group B), patients with AFLP were significantly younger (28.53±4.71vs.31.31±4.20,P<0.001) and had fewer numbers of pregnancies (1.741±0.915vs. 2.109±1.173, P=0.033). The rates of Pregnancy induced hypertension (21.8%vs.2.7%,P<0.001), twins (10.9%vs.1.4%, P=0.002), fetal growth restriction (FGR) (7.3% vs. 1.4%, P=0.044)and fetus male (96.4% vs 55%,P<0.001) before the diagnosis of AFLP were higher in groupA than groupB.The incidence of GDM seems less in group A than in group B(5.5% vs.13.2%),but there was no significant difference between two group（P=0.11）.Besides, the rates of other pathological pregnancy including hypothyrodism during pregnancy and placenta previa were not differ between groups.The mean values of ALT (219.18±240.11 vs.14.35±27.65, P<0.001), total bilirubin (160.83±112.54 vs.9.33±5.44, P<0.001), TBA(89.45±56.89vs.3.26±4.11,p<0.001) and CRE (162.91±89.84vs.46.83±11.62,P<0.001) were significantly higher in group A than in group B and the mean values of PLT（130.53±70.16 vs.205.35±56.03,P<0.001), HGB (104.27±23.44vs. 120.13±12.40,P<0.001), albumin (25.54±4.67vs. 33.26±3.99,P<0.001) and prothrombin activity (40.44±23.37vs.119.05±13.23,P<0.001) were significantly lower in group A than in group B. Also, the incidence of hypoglycemia(61.8% vs.20.9%,P<0.001) was significantly higher in group A than in group B(Table 1).
Characteristics and outcomes of the AFLP patients in our center
The clinical characteristics of the AFLP patients from the chosen studies were summarized in Table 2. Among all the patients of group A, 3 (5.5%) were diagnosed in the postpartum period. The mean gestational ages were 35.25±5.80 weeks in patients diagnosed before delivery and the mean days were 2.33±0.57days in patients diagnosed after delivery. Jaundice, Nausea or vomitting, anorexia, fatigue, like cold drinks, abdominal distension, diarrhea, bleeding（gingiva etc), right epigastric pain, disgusting oil, fever, pruritus and insomnia were found in 49(89.1%), 32(58.2%),27(49.1%), 25(45.5%), 17(30.9%), 9(16.4%), 6(10.9%), 6(10.9%), 5(9.1%), 4(7.3%), 4(7.3%),1(1.8%) and 1(1.8%)patients at the time of diagnosis, respectively. The median duration from diagnosis to delivery was 1.55±4.62 days and 75%(39/52) patients terminate the pregnancy at the day of diagnosis.(suppl Table 1). 78.8%(41/52) patients received cesearean section for terminating the pregnancy. 53.6%(22/41) patients received preventive plasma transfusion before the surgery and no one received artificial liver support during the treatment. During the surgery 25.45%(14/55) patients received intrauterine balloon after the terminating of pregnancy to prevent postpartum hemorrhage.No patient underwent liver transplantation.The mean gestational weeks at delivery were 36.26±2.58 weeks in group A, which were significant earlier than groupB.
As show in table 2, a significantly higher frequency of obeterical complications including placental abruption (12.7% vs.0.5%, P<0.05),meconium stained（II-III）(40% vs.8.6%, P<0.05), and postpartum hemorrhage (52.7% vs.12.3%, P<0.05) in group A than group B.No difference was found in the ccurence of oligohydramnios (7.3% vs.6.4%, p =0.807) between two groups. More patients need cesarean section (74.5% vs.49.5%, P<0.05) ,intrauterine balloon(21.8% vs.3.2%, P<0.05), preventive plasma transfusion(40% vs.0%, P<0.05), hysterectomy(or uterine artery embolism) (5.5% vs.0%, P<0.05), Blood Transfusion during the admission(61.8% vs.1.8%, P<0.05) and intensive care unit admission(61.8% vs.0.9%, P<0.05)in group A than group B. After the terminating the pregnancy, more patients in group A had poor wound healing of perineotomy or abdominal section than group B(14.5% vs. 0.5%, P<0.05).In terms of non obsterical complication, 83.6% coagulation disorders, 47.3%acute hepatic failure,85.5% Renal insufficiency,98.2% rising of total bile acids, 47.3% ascites , 18.2% encephalopathy, 3.6% hepatorenal syndrome,7.3% MOF,1.8% Shock and 12.7% infections (2 fungi infection ,1 severe pneumonia, 1acute pancreatitis,1 bacterial peritonitis,1biliary tract infection and 1 pressure sore) were found in group A.However, only one patients with slight coagulation disorders and 2.3% patients with rising of total bile acids in group B. Finally, three mothers in group A were died of multiple organ system failure and 1mothers did not complete recovery for too weak.In terms of fetal/infant complications, a significantly higher frequency of Preterm delivery(47.5% vs.5.4%, P<0.05),fetal distress(45.9% vs.3.1%, P<0.05),Asphyxia of newborn (24.6% vs.0.9%, P<0.05),NICU admission (19.7% vs.1.3%, P<0.05) and fetal/infant death(9.8% vs.0, P<0.05 )in group A than in group B .
When compared to those without negative outcomes, predictors of negative Fetus and Infants outcomes were younger mothers (27.00±2.57 vs.29.21±5.28，P=0.042)，more singleton rates (100% vs.72.73%,p=0.041),higher mean values of ALT(328.80±277.48 vs.164.60±194.25,P=0.011) and T-Bilirubin(208.46±108.89 vs.130.63±107.46,P=0.014), lower mean value of Prothrombin activity(29.51±23.10 vs.46.50±22.31,P=0.011). Besides,more patients in this group received preventive plasma transfusion(70.6% vs.27.3%, P=0.002)and intrauterine balloon pressure(47.1% vs.15.9%, P=0.011).(Table 3).There was no predictors of negative maternal outcomes were found in baseline values.(suppl 2).
The role of intrauterine balloon pressure in preventing further postpartum bleeding
To further evaluate the role of intrauterine balloon pressure, we stratified the 28 patients with postpartum hemorrhage more than 500ml into group A1(received intrauterine balloon pressure) and group A2( other methods instead intrauterine balloon pressure). Compared to patients in groupA2, less patients but without statistical significance were found in group A1 underwent refractory postpartum hemorrhage （>2000ml in delivery）(0% vs.31.3%, p =0.101 ), Hysterectomy(0% vs.12.5%, p =0.596 ),Negative marternal outcomes(16.7% vs.56.3%, p =0.083 ) for sample restriction (suppl 3).