Predicting placental abruption and previa in women with a previous cesarean delivery

The purpose of this study was to determine if placental abruption or previa in women with a history of a prior cesarean delivery (CD) can be predicted. A retrospective cohort study of pregnant women with previous CD was conducted in 17 centers between 1996 and 2000. Women developing placenta previa or abruption in the subsequent pregnancy were compared with those without these complications. Bivariate and multivariable techniques were used to develop predictive models for placenta previa or abruption. The area under the receiver-operator characteristic curves, sensitivity, specificity, and accuracy of the models were compared. Among 25,076 women with prior CD, there were 361 (15 per 1000 births) with placenta previa and 309 (13 per 1000 births) with abruption. The significant risk factors for these complications include advanced maternal age, Asian race, increased parity, illicit drug use, history of spontaneous abortion, and three or more prior cesarean deliveries. Prediction models for abruption and previa had poor sensitivity (12% and 13% for abruption and previa, respectively). In women with at least one prior cesarean delivery, the risk factors for placental previa and abruption can be identified. However, prediction models combining these risk factors were too inefficient to be useful.     

Risk factors for placental abruption in an Asian population

The objective of this study was to identify risk factors for placental abruption in an Asian population. The authors conducted a retrospective review of 37 245 Taiwanese women who delivered between July 1990 and December 2003. Pregnancies complicated by placenta previa, multiple gestation, and fetal anomalies were excluded. Multivariable logistic regression was used to adjust for potentially confounding variables and to identify independent risk factors for placental abruption. Three hundred thirty-two women had placental abruption (9 per 1000 singleton deliveries). Women who smoked during pregnancy (adjusted odds ratio [OR] = 8.4; 95% confidence interval [CI] = 3.0-23.9), had gestational hypertensive diseases (adjusted OR = 4.9; 95% CI = 3.3-7.3), pregnancies complicated by oligohydramnios (adjusted OR = 4.2; 95% CI = 2.7-6.7), polyhydramnios (adjusted OR = 3.3; 95% CI = 1.4-7.7), preterm premature rupture of membranes (adjusted OR = 1.9; 95% CI = 1.1-3.1), entanglement of umbilical cord (adjusted OR = 1.6; 95% CI = 1.2-2.1), were of or more than 35 years of age (adjusted OR = 1.5; 95% CI = 1.1-2.0), and had a low prepregnancy body mass index (adjusted OR = 1.3; 95% CI = 1.0-1.6) were at increased risk for placental abruption. Some risk factors for placental abruption among Taiwanese women are the same as those of other ethnic groups, whereas some of the risk factors are different.     

Racial variation in the frequency of intrapartum hemorrhage

OBJECTIVE: To evaluate racial variation in the frequency of intrapartum hemorrhage. METHODS: Using information from birth certificates of live singleton births in North Carolina from 1990 to 1997 (n = 807,759), we evaluated the frequency of intrapartum hemorrhage and its association with maternal race. Logistic regression models were used to evaluate the risk of any intrapartum hemorrhage, placental abruption, placenta previa, and unspecified hemorrhage in each racial group, adjusted for other risk factors. RESULTS: Black women had the highest rates of any hemorrhage (1.52% black, 1.47% white, 1.33% other race, P =.006) and placental abruption (0.79% black, 0.68% white, 0.56% other race, P =.001) but had lower rates of unspecified hemorrhage (0.37% black, 0.42% white, 0.42% other race, P =.001). Race was not associated with placenta previa. Maternal race remained associated with intrapartum hemorrhage after multivariable analysis, but the direction of the association was reversed. Black women were less likely to have any intrapartum hemorrhage (odds ratio [OR] 0.80, 95% confidence interval [CI] 0.77, 0.85), placental abruption (OR 0.76, 95% CI 0.70, 0.82), placenta previa (OR 0.89, 95% CI 0.81, 0.98), or other unspecified hemorrhage (OR 0.84, 95% CI 0.76, 0.92) compared with white women. Women of other minority races were at lower risk for placental abruption (OR 0.76, 95% CI 0.67, 0.87) but were comparable to white women for risk of placenta previa (OR 1.06, 95% CI 0.91, 1.24) and other unspecified hemorrhage (OR 1.02, 95% CI 0.88, 1.19). CONCLUSION: Although black women had higher rates of intrapartum hemorrhage than whites, the increased frequency was attributable to differences in clinical presentation and other risk factors.     

Placenta previa: obstetric risk factors and pregnancy outcome

Objective: To determine the incidence, obstetric risk factors and perinatal outcome of placenta previa. Study design: All singleton deliveries at our institution between 1990 and 1998 complicated with placenta previa were compared with those without placenta previa. Results: Placenta previa complicated 0.38% ( n = 298) of all singleton deliveries ( n = 78 524). A back-step multiple logistic regression model found the following factors to be independently correlated with the occurrence of placenta previa: maternal age above 40 years (OR 3.1, 95% CI 2.0-4.9), infertility treatments (OR 3.1, 95% CI 1.8-5.6), a previous Cesarean section (OR 1.8, 95% CI 1.4-2.4), a history of habitual abortions (OR 1.3, 95% CI 1.3-2.7) and Jewish ethnicity (OR 1.3, 95% CI 1.1-1.8). Pregnancies complicated with placenta previa had significantly higher rates of second-trimester bleeding (OR 156.0, 95% CI 87.2-277.5), pathological presentations (OR 7.6, 95% CI 5.7-10.1), abruptio placentae (OR 13.1, 95% CI 8.2-20.7), congenital malformations (OR 2.6, 95% CI 1.5-4.2), perinatal mortality (OR 2.6, 95% CI 1.1-5.6), Cesarean delivery (OR 57.4, 95% CI 40.7-81.4), Apgar scores at 5 min lower than 7 (OR 4.4, 95% CI 2.3-8.3), placenta accreta (OR 3.6, 95% CI 1.1-9.9) postpartum hemorrhage (OR 3.8, 95% CI 1.2-10.5), postpartum anemia (OR 5.5, 95% CI 4.4-6.9) and delayed maternal and infant discharge from the hospital (OR 10.9, 95% CI 7.3-16.1) as compared to pregnancies without placenta previa. In a multivariable analysis investigating risk factors for perinatal mortality, the following were found to be independent significant factors: congenital malformations, placental abruption, pathological presentations and preterm delivery. In contrast, placenta previa and Cesarean section were found to be protective factors against the occurrence of perinatal mortality while controlling for confounders. Conclusion: Although an abnormal implantation per se was not an independent risk factor for perinatal mortality, placenta previa should be considered as a marker for possible obstetric complications. Hence, the detection of placenta previa should encourage a careful evaluation with timely delivery in order to reduce the associated maternal and perinatal complications.     

Placenta previa: obstetric risk factors and pregnancy outcome.

OBJECTIVE: To determine the incidence, obstetric risk factors and perinatal outcome of placenta previa. STUDY DESIGN: All singleton deliveries at our institution between 1990 and 1998 complicated with placenta previa were compared with those without placenta previa. RESULTS: Placenta previa complicated 0.38% (n = 298) of all singleton deliveries (n = 78 524). A back-step multiple logistic regression model found the following factors to be independently correlated with the occurrence of placenta previa: maternal age above 40 years (OR 3.1, 95% CI 2.0-4.9), infertility treatments (OR 3.1, 95% CI 1.8-5.6), a previous Cesarean section (OR 1.8, 95% CI 1.4-2.4), a history of habitual abortions (OR 1.3, 95% CI 1.3-2.7) and Jewish ethnicity (OR 1.3, 95% CI 1.1-1.8). Pregnancies complicated with placenta previa had significantly higher rates of second-trimester bleeding (OR 156.0, 95% CI 87.2-277.5), pathological presentations (OR 7.6, 95% CI 5.7-10.1), abruptio placentae (OR 13.1, 95% CI 8.2-20.7), congenital malformations (OR 2.6, 95% CI 1.5-4.2), perinatal mortality (OR 2.6, 95% CI 1.1-5.6), Cesarean delivery (OR 57.4, 95% CI 40.7-81.4), Apgar scores at 5 min lower than 7 (OR 4.4, 95% CI 2.3-8.3), placenta accreta (OR 3.6, 95% CI 1.1-9.9) postpartum hemorrhage (OR 3.8, 95% CI 1.2-10.5), postpartum anemia (OR 5.5, 95% CI 4.4-6.9) and delayed maternal and infant discharge from the hospital (OR 10.9, 95% CI 7.3-16.1) as compared to pregnancies without placenta previa. In a multivariable analysis investigating risk factors for perinatal mortality, the following were found to be independent significant factors: congenital malformations, placental abruption, pathological presentations and preterm delivery. In contrast, placenta previa and Cesarean section were found to be protective factors against the occurrence of perinatal mortality while controlling for confounders. CONCLUSION: Although an abnormal implantation per se was not an independent risk factor for perinatal mortality, placenta previa should be considered as a marker for possible obstetric complications. Hence, the detection of placenta previa should encourage a careful evaluation with timely delivery in order to reduce the associated maternal and perinatal complications.     

Clinical presentation and risk factors of placental abruption

BACKGROUND: To study the risk factors of placental abruption during the index pregnancy. METHODS: One hundred and ninety-eight women with placental abruption and 396 control women were identified among 46,742 women who delivered at a tertiary referral university hospital between 1997 and 2001. Clinical variables were compared between the groups. Multivariate logistic regression analysis was applied to identify independent risk factors. The clinical manifestations of placental abruption were also studied. RESULTS: The overall incidence of placental abruption was 0.42%. The independent risk factors were maternal (adjusted OR 1.8; 95% CI 1.1, 2.9) and paternal smoking (2.2; 1.3, 3.6), use of alcohol (2.2; 1.1, 4.4), placenta previa (5.7; 1.4, 23.1), pre-eclampsia (2.7; 1.3, 5.6), and chorioamnionitis (3.3; 1.0, 10.0). Vaginal bleeding (70%), abdominal pain (51%), bloody amniotic fluid (50%), and fetal heart rate abnormalities (69%) were the most common manifestations. Neither bleeding nor pain was present in 19% of the cases. Overall, 59% had preterm labor (OR 12.9; 95% CI 8.3, 19.8), and 91% were delivered by cesarean section (34.7; 20.0, 60.1). Of the newborns, 25% were growth restricted. The perinatal mortality rate was 9.2% (OR 10.1; 95% CI 3.4, 30.1). Retroplacental blood clot was seen by ultrasound in 15% of the cases. CONCLUSIONS: Maternal alcohol consumption and smoking, and smoking by the partner turned out to be independent risk factors for placental abruption. Smoking by both partners multiplied the risk. The liberal use of ultrasound examination contributed little to the management of women with placental abruption.     

Association of caesarean delivery for first birth with placenta praevia and placental abruption in second pregnancy

Objective  To quantify the risk of placenta praevia and placental abruption in singleton, second pregnancies after a caesarean delivery of the first pregnancy.
Design  Retrospective cohort study.
Setting  Linked birth and infant mortality database of the USA between 1995 and 2000.
Population  A total of 5 146 742 singleton second pregnancies were available for the final analysis after excluding missing information.
Methods  Multiple logistic regressions were used to describe the relationship between caesarean section at first birth and placenta praevia and placental abruption in second-birth singletons.
Main outcome measures  Placenta praevia and placental abruption.
Results  Placenta praevia was recorded in 4.4 per 1000 second-birth singletons whose first births delivered by caesarean section and 2.7 per 1000 second-birth singletons whose first births delivered vaginally. About 6.8 per 1000 births were complicated with placental abruption in second-birth singletons whose first births delivered by caesarean section and 4.8 per 1000 birth in second-birth singletons whose first births delivered vaginally. The adjusted odds ratio (95% CIs) of previous caesarean section for placenta praevia in following second pregnancies was 1.47 (1.41, 1.52) after controlling for maternal age, race, education, marital status, maternal drinking and smoking during pregnancy, adequacy of prenatal care, and fetal gender. The corresponding figure for placental abruption was 1.40 (1.36, 1.45).
Conclusion  Caesarean section for first live birth is associated with a 47% increased risk of placenta praevia and 40% increased risk of placental abruption in second pregnancy with a singleton.     

Cervical varix complicating marginal placenta previa: a unique coexistence

Uterine cervical varix (CV) is a very rare condition during pregnancy and may cause moderate to severe hemorrhage. We present the third reported case of huge CV coexisting with placenta previa in the English literature. A 40-year-old chronic hypertensive patient with marginal placenta previa also had cervical varix causing hemorrhage. At the 38th gestational week emergent cesarean section was performed because of placental abruption. Placenta previa is a risk factor for CV and patients with placenta previa who have moderate bleeding should be examined for this coexistence. The choice of management is close follow-up and cesarean section close to term.     

Placental ratio and risk of velamentous umbilical cord insertion are increased in women with placenta previa

The purpose of this study was to explore the maternal risk profile and obstetric outcome in pregnancies affected by placenta previa. Retrospective case-control study involved all women (93 [0.37%] women with diagnosed placenta previa and 24,857 unaffected controls) who gave birth to singleton infants at Kuopio University Hospital between the years 1989 and 2000. Grand multiparity, infertility problems, and advanced maternal age were independent risk factors of placenta previa, with adjusted relative risks of 5.8, 3.7, and 2.4, respectively. Most women with placenta previa (88.2%) underwent cesarean delivery before term. They also more often had velamentous umbilical cord insertion (7.5%) and higher placental-to-birthweight ratios than the controls. Placenta previa was associated with risks of preterm delivery, low birthweight infants, and need for neonatal intensive care, at odds ratios of 27.7, 7.4, and 3.4, respectively. In conclusion, placenta previa is an infrequent pregnancy complication associated with multiparity, advanced maternal age, infertility problems, elevated placental ratio, and velamentous umbilical cord insertion.     

新生儿窒息产前产时危险因素分析

目的探讨产前、产时新生儿窒息的危险因素,为临床干预提供依据,以降低新生儿窒息发生率。 方法回顾分析2009年1月1日至2016年12月31日在广州医科大学附属第三医院分娩的40 319例活产新生儿,根据是否发生新生儿窒息分为窒息组(1415例)和非窒息组(38 904)例,采用多元Logistic回归分析,筛查对发生窒息有意义的危险因素。 结果新生儿窒息发生率为3.5%,子痫前期、子痫、中央性前置胎盘、胎盘早剥、脐带脱垂、贫血、臀位均为新生儿窒息的独立危险因素(OR值分别为2.190、9.405、2.067、2.384、3.309、1.524、1.679,P均<0.05)。 结论对于有高危因素的孕产妇,应加强围生期保健,及时处理高危妊娠因素,以预防和减少新生儿窒息的发生。     

Placenta previa in singleton and twin births in the United States, 1989 through 1998: a comparison of risk factor profiles and associated conditions

OBJECTIVE: The purpose of this study was to compare risk factor profiles for placenta previa between singleton and twin live births. STUDY DESIGN: This cohort study was based on United States natality data files (1989 through 1998) and comprised 37,956,020 singleton births and 961,578 twin births. Women who were diagnosed with placenta previa were included only if they were delivered by cesarean delivery. Risk factors for placenta previa that were examined included sociodemographic (age, gravidity, education, marital status, and race), behavioral (prenatal care, smoking, and alcohol use), previous preterm birth, and medical and obstetric factors. Effect modification between maternal age and gravidity and the dose-response relationship with number of cigarettes smoked/day on placenta previa risk were also evaluated. RESULTS: The rate of placenta previa was 40% higher among twin births (3.9 per 1,000 live births, n = 3,793 births) than among singleton births (2.8 per 1,000 live births, n = 104,754 births). Comparison of risk factors for placenta previa between the singleton and twin births revealed fairly similar risk factor profiles. Compared with primigravid women <20 years old, the risk for placenta previa increased by advancing age and by increasing number of pregnancies among both singleton and twin births. The number of cigarettes smoked per day also showed a dose-response trend for placenta previa risk in the two groups. CONCLUSION: The increased rate of placenta previa among twin births underscores the need to monitor carefully such pregnancies with heightened suspicion and awareness for the development of this condition.     

The effect of placenta previa on neonatal mortality: a population-based study in the United States, 1989 through 1997

OBJECTIVE: The purpose of the study was to explore the associations of placenta previa with preterm delivery, growth restriction, and neonatal survival. STUDY DESIGN: A retrospective cohort study was performed of live births in the United States (1989-1991 and 1995-1997) that used the national linked birth/infant death records from 22,368,235 singleton pregnancies. The diagnosis of previa was restricted to those live births that were delivered (> or =24 weeks) by cesarean delivery. We evaluated gestational age and birth weight-specific risk of neonatal deaths (within the first 28 days) in relation to placenta previa. Fetal growth was assessed in centiles of birth weight (<3rd, 3rd-4th, 5th-9th, 10th-90th, and >90th centile), adjusted for gestational age. All analyses were adjusted for the confounding effects of the year of delivery, maternal age, gravidity, education, prenatal care, marital status, and race/ethnicity. RESULTS: Placenta previa was recorded in 2.8 per 1000 live births (n = 61,711). Neonatal mortality rate was 10.7 with previa, compared with 2.5 per 1,000 among other pregnancies (relative risk, 4.3; 95% confidence interval, 4.0,4.8). At 28 to 36 weeks, babies born to women with placenta previa weighed, on average, 210 g lower than babies born to women without placenta previa (P <.001). Compared with babies born to women without previa, the risk of death from placenta previa was lower among preterm babies (<37 weeks of gestation), with a crossover at 37 weeks where the mortality rate was higher for babies born to women with placenta previa than for babies born to women without placenta previa. This crossover also persisted in an analysis by birth weight and term births (delivered at > or =37 weeks of gestation). Mortality rates for term births were higher among babies born to women with placenta previa than among babies born women without placenta previa who were at the 10th to 90th centile (relative risk, 1.9; 95% confidence interval, 1.3, 2.8), and those at >90th centile (relative risk, 3.6; 95% confidence interval, 1.3, 9.6). Among preterm births, however, placenta previa was not associated with increased neonatal mortality by fetal growth centiles. CONCLUSION: The risk of neonatal mortality was higher for babies born to women with placenta previa than for babies born to women without placenta previa who were delivered at > or =37 weeks of gestation. Pregnancies that are diagnosed with placenta previa must be monitored carefully, especially as they approach term.     

Previous cesarean delivery and risks of placenta previa and placental abruption

OBJECTIVE: To examine the association between cesarean delivery and previa and abruption in subsequent pregnancies. METHODS: A retrospective cohort study of first 2 (n = 156,475) and first 3 (n = 31,102) consecutive singleton pregnancies using the 1989-1997 Missouri longitudinally linked data were performed. Relative risk (RR) was used to quantify the associations between cesarean delivery and risks of previa and abruption in subsequent pregnancies, after adjusting for several confounders. RESULTS: Rates of previa and abruption were 4.4 (n = 694) and 7.9 (n = 1,243) per 1,000 births, respectively. The pregnancy after a cesarean delivery was associated with increased risk of previa (0.63%) compared with a vaginal delivery (0.38%, RR 1.5, 95% confidence interval [CI] 1.3-1.8). Cesarean delivery in the first and second births conferred a two-fold increased risk of previa in the third pregnancy (RR 2.0, 95% CI 1.3-3.0) compared with first two vaginal deliveries. Women with a cesarean first birth were more likely to have an abruption in the second pregnancy (0.95%) compared with women who had a vaginal first birth (0.74%, RR 1.3, 95% CI 1.2-1.5). Two consecutive cesarean deliveries were associated with a 30% increased risk of abruption in the third pregnancy (RR 1.3, 95% CI 1.0-1.8). A second pregnancy within a year after a cesarean delivery was associated with increased risks of previa (RR 1.7, 95% CI 0.9-3.1) and abruption (RR 1.5, 95% CI 1.1-2.3). CONCLUSION: A cesarean first birth is associated with increased risks of previa and abruption in the second pregnancy. There is a dose-response pattern in the risk of previa, with increasing number of prior cesarean deliveries. A short interpregnancy interval is associated with increased risks of previa and abruption. LEVEL OF EVIDENCE: II-2.     

胎盘植入性疾病的危险因素及妊娠结局分析

目的探讨胎盘植入性疾病的危险因素及妊娠结局。 方法回顾性分析2009年1月至2017年12月广州医科大学附属第三医院/广州重症孕产妇救治中心围产资料数据库中信息完整的单胎妊娠孕妇48 650例临床资料,将这些孕妇分为胎盘植入性疾病组和非胎盘植入性疾病组,分析胎盘植入性疾病的危险因素及其妊娠结局。 结果单因素分析显示,年龄≥35岁、高中教育水平及以下、孕次≥3次、经产妇、人工流产史、剖宫产史、体外受精－胚胎移植受孕、合并前置胎盘是胎盘植入性疾病的相关危险因素(P<0.05)。多因素logistic回归分析显示,胎盘植入性疾病的独立危险因素为剖宫产史(OR＝2.254,95%CI：1.917～2.650)、体外受精－胚胎移植受孕(OR＝1.591,95%CI：1.212～2.089)、合并前置胎盘(OR＝28.282,95%CI：24.338～32.866);与非胎盘植入性疾病产妇相比,患有胎盘植入性疾病产妇早产、剖宫产、产后出血、弥散性血管内凝血、产褥期感染、子宫切除、低出生体重儿、新生儿Apgar评分相对较低(1 min)、产妇入住重症监护病房的发生率明显升高(P<0.05)。 结论剖宫产史、辅助生殖受孕、合并前置胎盘是引起胎盘植入性疾病的独立危险因素,胎盘植入性疾病的妊娠结局不良。     

Maternal and perinatal outcome of pregnancies after the age of 45

OBJECTIVE: To describe the maternal and perinatal outcome of pregnancies in women aged 45 years or more at the time of delivery and to compare them with pregnancies in women aged between 20 and 29 years. METHODS: A retrospective review of hospital deliveries after 28 weeks gestation was performed at the Princess Badeea Teaching Hospital in North Jordan for patients delivered between 1st April 1994 and 31st December 1997. We compared the maternal and perinatal outcome of pregnancies in women aged of 45 years or more (study group, n = 114) with women aged between 20-29 years (control group, n = 121) delivered at the same hospital during the same period. RESULTS: The incidence of pregnant women aged 45 years or more was 3.3 per 1,000 births. The median maternal age was 45 years. The majority of women (81.6%) were 45 to 46 years old. Gravidity and parity was significantly higher in the study group (p < 0.0001), also antenatal and medical complications as pre-eclampsia and diabetes mellitus were higher in the study group. Caesarean section rate, incidences of placental abruption and placenta previa were more common in older patients compared with young patients (32.4 vs 10.7%, 6.1 vs 0.8% and 4.4 vs 1.6%, respectively). There were no differences in the incidences of neonatal deaths, lethal malformations and fetal weight between the 2 groups. CONCLUSION: Women aged 45 years or more at delivery may expect a good pregnancy outcome but should expect a higher incidences of placental abruption, placenta previa, preeclampsia and caesarean delivery.     

The relationship of placenta previa and history of induced abortion.

OBJECTIVES: We evaluated the risk of placenta previa being associated with a history of induced abortion by different surgical procedures. METHODS: Cases (n=192) were women who had a singleton delivery complicated by placenta previa at a major obstetric care hospital in western Washington state between April 1, 1990 and December 31, 1992. Controls (n=622) were women with singleton deliveries not complicated by placenta previa or abruption. Odds ratios, determined by logistic regression, approximate the relative risks. RESULTS: Vacuum aspiration abortion was not associated with an increased risk of placenta previa (OR 0.9, 95% CI 0.6-1.5). However, the risk of placenta previa increased with the number of sharp curettage abortions (OR 2.9, 95% CI 1.0-8.5 for > or =3). CONCLUSIONS: Risk of placenta previa may be increased in a dose response fashion by multiple sharp curettage abortions. However, vacuum aspiration does not confer an increased risk, and may be a better alternative.     

Prepregnancy risk factors for placental abruption

BACKGROUND: To define the prepregnancy risk factors for placental abruption. METHODS: One hundred and ninety-eight women with placental abruption and 396 control women without placental abruption were retrospectively identified among 46,742 women who delivered at a tertiary referral university hospital between 1997 and 2001. Relevant historical and clinical variables were compared between the groups. Multivariate logistic regression analysis was applied to identify independent risk factors. RESULTS: The overall incidence of placental abruption was 0.42%. Placental abruption recurred in 8.8% of the cases. The independent risk factors were smoking (OR 1.7; 95% CI 1.1, 2.7), uterine malformation (OR 8.1; 1.7, 40), previous cesarean section (OR 1.7; 1.1, 2.8), and history of placental abruption (OR 4.5; 1.1, 18). CONCLUSIONS: Although univariate analysis identified many risk factors, only smoking, uterine malformation, previous cesarean section, and history of placental abruption remained significant after multivariate analysis, increasing the risk of placental abruption in subsequent pregnancy. It may be possible to approximate the risk for placental abruption based on these simple prepregnancy risk factors.     

The risk of placental abruption and placenta previa in pregnant women with chronic hepatitis B viral infection: A systematic review and meta-analysis

Introduction

Several epidemiological studies have found a positive association between chronic hepatitis B virus (CHB) infection and the risk of placental abruption and placenta previa, but various studies have reported conflicting findings. The objective was to systematically review the literature to determine a possible association between CHB infection and these two placental complications.

Methods

We conducted a computerized search in electronic database through March 1, 2014, supplemented with a manual search of reference lists, to identify original published research on placental abruption and placenta previa rates in women with CHB infection. Data were independently extracted, and relative risks were calculated. The meta-analysis was performed using Stata version 10.0 software.

Results

Five studies involving 9088 placenta previa cases were identified. No significant association between CHB infection and placenta previa was identified (OR = 0.98, 95% CI = 0.60–1.62). Five studies involving 15571 placental abruption cases were identified. No significant association between CHB infection and placental abruption was identified (OR = 1.42, 95% CI, 0.93–2.15).

Discussion

The immune response against the virus represents a key factor in determining infection outcomes. No observation of significant increased risk of the placental complications could be partially explained by the complex immune response during CHB infection.

Conclusions

Our meta-analysis found no evidence of significant associations between CHB infection and increased risk of placental abruption as well as placenta previa. Further well-designed studies were warranted to assess any potential association between CHB infection and increased risk of placental abruption as well as placenta previa.     

Elevated maternal second-trimester serum alpha-fetoprotein as a risk factor for placental abruption

OBJECTIVE: To analyze the association of second-trimester maternal serum alpha-fetoprotein (MSAFP) and free beta human chorionic gonadotrophin (MSbeta-hCG) levels to placental abruption. METHODS: Fifty-seven women with placental abruption and 108 control women without placental abruption were tested for second-trimester MSAFP and MSbeta-hCG levels as a part of a trisomy 21 screening program. Discriminatory cutoff levels for MSAFP were sought to predict placental abruption. RESULTS: The median of the MSAFP multiples of median (MoM) (1.21) was significantly higher in the abruption group than in the control group (1.07) (p = 0.004). In multivariate analysis, elevated MSAFP remained an independent risk factor for placental abruption when adjusting for other risk factors (parity >/= 3, smoking, previous placental abruption, preeclampsia, bleeding in II or III trimester, and placenta previa). MSAFP >/= 1.5 MoM had a sensitivity of 29% and a false-positive rate of 10%. The levels of the MSbeta-hCG MoM did not differ between the cases and the controls. CONCLUSION: Although second-trimester MSAFP levels are higher in women with subsequent placental abruption, the clinical usefulness of this test is limited due to low sensitivity and high false-positive rate.