The Risk Factors Of Pernicious Placenta Previa And Prenatal Diagnosis Of Placenta Accreta

Pernicious placenta previa was first proposed in the article which named placenta previa and accreta after previous caesarean section by Chattopadhyay in 1993, it refers to the cases in pregnant women who have placenta previa and placenta adhering to the scar area of uterus wall, no matter with placenta accreta or not. With the increased possibility of unsubstantiated verified of caesarean section and uterus surgery like caesarean section and myomectomy, the occurrence of pernicious placenta previa has also been elevated each year. Pernicious placenta previa with or without placenta accreta usual occurred in the patients with previous caesarean section, the reason may be associated with the destruction of normal endometrum of anatomical structures and the formation of scar. With great possibility of accompanied placenta accreta, unnoticed pernicious placenta previa before giving birth of the baby could often lead to situations endanger lives such as uncontrolling heavy bleeding, uterine perforation, secondary infection and disseminated intravascular coagulation.The specific reasons for pernicious placenta previa is still unknown, the risk factors are differently reported in varied studies which have even got substantial controversial results. It’s reported that pernicious placenta previa is relevant with repeated childbirth, repeated abortion, caesarean section history, high-age, position of placenta, uterus surgery, childbirth spacing and even the residence. All the controversial results got in pernicious placenta previa study have left great troubles on frontline obstetricians. Pregnant women with high risk factor should be diagnosed as soon as possible. Clinical measures to diagnose pernicious placenta previa are usually ultrasound or nuclear magnetic resonance, each has its own limitations. The grope in biomarkers in serum to diagnose pernicious placenta previa these years may elevate its prenatal diagnosis. It’s identified that pernicious placenta previa is well correlated with placenta accrete, while pernicious placenta previa is often accompanied by placenta accrete.Given all that, studies on risk factors could increase our awareness of pernicious placenta previa, and pregnant women with high risk factors should be diagnosed as soon as possible. Our study had been divided into two parts:first:analysis of clinical data of 118 pernicious placenta previa cases to explore the incidence, risk factors, prognosis of the both baby and mother, timing for surgery and principles for the surgery. Second:to investigate the value of biomarkers in serum diagnosing pernicious placenta previa with accreta and increase our awareness of pernicious placenta previa.First chapter analysis of clinical data of 118 pernicious placenta previa casesObjective:Through summary analysis of the clinical data of 118 cases of pernicious placenta previa to discuss its incidence rate, risk factors, maternal and neonatal outcomes, the timing of caesarean section and the principle of surgical treatment.Methods:Retrospective analysis of complete medical records of patients who delivered at the maternal health and child care hospital of Fo Shan affiliated the southern medical university with delivery from Jan 2013 to Dec 2015 were included with documentation of a histopathologic diagnosis of pernicious placenta previa were identified and matched to patients with placenta previa by year of delivery. All pregnant women with the diagnosis of pernicious placenta previa as the observation group, The diagnosis of placenta previa as the control group. Thereafter, clinical characteristics, incidence rate, maternal and neonatal outcomes, the timing of caesarean section and the principle of surgical treatment in the two groups were investigated retrospectively.Results:(1) The occurrence of pernicious placenta previa was increased year by year. The occurrence of pernicious placenta previa was increased from 0.318% in 2013 year to 0.464% in 2015 year, The occurrence of pernicious placenta previa with placenta accreta was also increased from 0.236% in 2013 year to 0.294% in 2015 year.84 cases of placenta accreta were diagnosed among 118 cases of pernicious placenta previa, the incidence of placenta accreta in pernicious placenta previa was up to 71.186%. However,39 cases of placenta accreta were diagnosed among 282 cases of pernicious placenta previa, the incidence of placenta accreta in the group of placenta previa was only 13.829%. The pernicious placenta previa with placenta accreta is 4.435 times of the group of placenta previa. And not only that, different types of placenta accreta was a difference in the two groups.32 cases of placenta accreta,40cases of placenta increta and 12 cases of placenta percreta were observed in the group of pernicious placenta previa, however, only 31 cases of placenta accreta,8cases of placenta increta and zero cases of placenta percreta were distributed in the group of placenta previa. significantly values (x2 = 145.621, P<0.0001) were observed for different types of placenta accreta in the two groups.(2) Compared with the placenta previa, cesarean section is the main risk factors of pernicious placenta previa.104 cases with two caesarean sections in 118 cases of pernicious placenta previa (104/118,88.1%),14 patients with three times or more caesarean sections were observed in the group of pernicious placenta previa (14/118,11.9%).248cases with one caesarean section and 34 patients with two times or more caesarean sections in the group of placenta previa. The difference of number of cesarean section in the two groups was statistically significant(x2=16.385, P< 0.001). The single factor analysis showed that gravidity, parity and hepatitis B virus carrier might be risk factors for pernicious placenta previa, however, delivery times, height and IVF-ET may be protective factors of pernicious placenta previa. In order to control confounding factors, univariate and multivariate stepwise regression analysis were performed to assess the factors related to pernicious placenta previa. The result showed that cesarean section is the main risk factors of pernicious placenta previa(P< 0.001)(3) 5 cases occurred uncontrolled hemorrhagic shock in 282 patients with placenta previa compared with 8 cases in the group of pernicious placenta previa, there were significant difference in the two groups (Z=6.632,P<0.001). No case was performed supracervical hysterectomy in the group of placenta previa, but 7 patients were performed supracervical hysterectomy in the group of pernicious placenta previa because of uncontrolled massive haemorrhage. Different hemostatic methods including the ligation of the upper branch of uterine artery and balloon dilation in the cesarean section with pernicious placenta previa were higher than that in placenta previa group(P＜0.001).109 cases of pernicious placenta previa needed varying amounts of red blood cells in the time of introperation and postoperation, however,95 patients in the group of placenta previa needed from Iunit to 18units of red blood cells. The difference was statistically significant in two groups(x2 = 114.646, P＜0.001). Through the comparison of the difference of bleeding volume among the pernicious placenta previa with different types of placenta accreta. Our results showed as follow: pernicious placenta previa without placenta accreta< pernicious placenta previa with placenta accreta< pernicious placenta previa with placenta increta< pernicious placenta previa with placenta percreta. Moreover, The difference was statistically significant. Although blood transfusions increased with the depth of placenta invasion, a phenomenon drew our attention which that there was no statistically significant in two groups of pernicious placenta previa with placenta accreta and pernicious placenta previa with placenta increta.(4) Through the comparison of the difference of neonatal outcomes in the groups of pernicious placenta previa and placenta accreta,2 fetuses(There was one death in each group) were death in maternal womb before hospital delivery.There was no statistically significant in two groups of neonatal birth weight(t=1.190, P=0.235). In the aspect of preterm birth,88 neonatus were born before 37 weeks gestation in the group of pernicious placenta previa (88/117,75.2%) compared with 150 neonatus were born before 37 weeks gestation in the placenta accreta group(150/281,53.4%). The occurrence of preterm birth in the pernicious placenta previa group was obvious higher than the placenta previa group. The result showed that there was a positive association between 1 minute of Apgar score and neonatal asphyxia. Although 1 minute of Apgar score and 5 minutes of Apgar score in the group of pernicious placenta previa were lower than the placenta previa group(P< 0.001),5 minutes of Apgar score showed no statistically significant in two groups. Neonatal pneumonia and neonatal hyperbilirubinemia were also no significant in two groups of pernicious placenta previa and placenta previa (P=0.624,0.101).Conclusions:(1) The occurrence of pernicious placenta previa was increased year by year. The incidence of placenta accreta in pernicious placenta previa was up to 71.186%. Most of pernicious placenta previa was combination with placenta increta, whereas a lot of placenta previa was combination with placenta accreta(2) Compared with the placenta previa, cesarean section is the main risk factors of pernicious placenta previa(3) Pernicious placenta previa have already presented a threat to maternal health and life safety, therefore, it is necessary to choose the timing of caesarean section and surgical methods by different people.(4) Although pernicious placenta previa can easily induce premature labor and neonatal asphyxia, it is no association with remote neonatal outcomes.The second chapter Pernicious placenta previa with accreta is association with abnormal elevated martenal serum markersObjective:To estimate the predictive values of abnormal elevated mid-trimester serum alpha-Fetoprotein(AFP), free beta human chorionic gonadotropin (fbhCG) and unconjugated estriol (uE3) for pernicious placenta previa (PPP) with accreta.Methods:Retrospective analysis of complete medical records of patients who delivered at the maternal health and child care hospital of Fo Shan affiliated the southern medical university with delivery from Jan 2013 to Dec 2014 were included with documentation of a histopathologic diagnosis of pernicious placenta previa with accreta were identified and matched to patients with placenta previa and placenta accreta by year of delivery. Patients with previous caesarean section of the control group consisted of 60 serum samples (about 1:1 ratio) matched by maternal age, randomly selected from the routine second trimester maternal serum screening databases. Multiple gestations, structural or chromosomal abnormalities, or fetal death or for lack of available follow-up were excluded. A blood sample was collected from each pregnant woman at 15 to 20+6 weeks in EDTA-containing tubes and centrifuged at 3000 rounds for 10minutes. The resulting serum was transferred to new tubes. Maternal serum AFP, fbhCG and uE3 were measured using the Auto DELFIA (Perkin Elmer, Waltham, MA, USA). The biochemistry marker concentrations were expressed as multiples of the median(MoMs) and are routinely adjusted for known confounding maternal and pregnancy characteristics including maternal cigarette smoking, maternal weight, gestational age, and conception using assisted reproductive techniques. Informed consent for biochemical testing was obtained for each patient prior to blood sampling as part of routine antenatal care.Results:Among 119 patients in our retrospective investigation,12 cases distributed in the group of pernicious placenta previa with accreta,8 cases of placenta accreta,39 cases of previa alone and 60 normal controls were included in our retrospective case-control. Nine of the twelve(75%) women had elevated AFP. Moreover, half of patients in the group of pernicious placenta previa with accreta had AFP levels greater than 2.0 MoM (2.035-3.031). Mean AFP MoM was 1.065 in the control group, 1.202 MoM in previa,1.208 MoM in placenta accreta compared with 1.743 MoM in pernicious placenta previa with accreta group, significantly higher values (P＜0.001) were observed for AFP MoM values in the pernicious placenta previa with accreta group. Although AFP MoM values in the group of placenta accreta were higher than the group of placenta previa and normal cases, there were no signification of comparison with AFP MoM values(P=0.971 and 0.441).Conclusions:(1) Elevated martenal serum AFP MoM values may provide useful information for the early identification of abnormally pernicious placenta previa with accreta.(2) Mid-trimester serum free beta human chorionic gonadotropin (fbhCG) and unconjugated estriol (uE3) may not provide diagnostic value for the patients with pernicious placenta previa or placenta accreta.(3) There is no evidence to support that Placenta accreta is association with elevated mid-trimester serum AFP MoM values.