Effect of placenta previa on fetal growth restriction and stillbirth

Aim

To examine the association between placenta previa and adverse perinatal outcomes such as low birth weight, preterm delivery, stillbirth and fetal growth restriction (FGR).

Methods

This retrospective cohort study includes 12,034 delivered pregnant women who were recruited for the study between 2004 and 2010 in Ege University Hospital. Data were collected by browsing the clinic??s archives. The association between placenta previa and adverse perinatal outcomes was determined via Chi-square tests and Student??s t test. Logistic regression analysis was used to adjust for confounding factors in evaluating the association between placenta previa and the adverse perinatal outcomes.

Results

There was no significant relationship between placenta previa and FGR or stillbirth. Low birth weight and preterm delivery were significantly higher in the placenta previa group. According to logistic regression analysis, low birth weight was associated with an OR of 3.01 (95?% CI 2.05?C4.52) and preterm delivery was associated with an OR of 8.14 (95?% CI 5.60?C11.83); while, placenta previa did not affect FGR and stillbirth significantly.

Conclusion

Although there is no consensus on the association between placenta previa and FGR in previous studies, we suggest that placenta previa is not a reason for placental insufficiency. Management of placenta previa especially depends on maternal hemodynamic parameters such as heavy hemorrhage and hypotensive shock rather than fetal well-being protocols based on serial growth ultrasound and fetal Doppler investigation.     

Effect of placenta previa on fetal growth and development]

A retrospective study of 151 fetuses born of mothers with placenta previa in the maternity and our hospital in 1984-1991 was done. This study aimed at determining whether placenta previa affects growth and to what extend. We recorded the birth weight, crown-heel length, head and chest circumferences of each of the 151 fetuses. After calculating the average of each item. According to gestational week and type of placenta previa, they were compared with the 50th percentile numbers in normal fetuses of the same gestational age. The results were among the 151 features, born of mothers with placenta previa 19 (12.6%) suffered from intrauterine growth retardation, 80(53.0%) with birth weight less than normal fetuses, and 52(34.4%) with birth weight basically the same as normal fetuses. Most of the fetuses with birth weight less than normal, were born of mothers with total or partial placenta previa while most of those with birth weight basically the same as normal fetuses. At 28th to 32nd week were born mothers with lowly placenta previa of gestation there was no obvious difference between the birth weights of fetuses of placenta previa mothers and normal pregnancies (P greater than 0.05). But from 33rd week to 40th week, the difference became obvious (P less than 0.05); the chest circumference in fetuses of total and partial placenta previa cases obviously less (P less than 0.05). So we may say that placenta previa affects fetal weight gain, especially from 33rd week and the chest circumference, in the last three weeks.     

Early placenta previa and delivery outcome

Ultrasound scan showed some degree of placenta previa in 503 patients. Of this group, 5.6% (28) had clinically significant bleeding or documented placenta previa at delivery. A scoring system based on placental localization was not successful in predicting who was at high risk for bleeding. However, the likelihood of clinically excessive bleeding did significantly increase if the placenta previa was noted after 30 weeks' gestation. The study did not find a greater incidence of small-for-gestational-age babies in women with low-lying placentas.     

Early preterm delivery due to placenta previa is an independent risk factor for a subsequent spontaneous preterm birth

ABSTRACT: BACKGROUND: To determine whether patients with placenta previa who delivered preterm have an increased risk for recurrent spontaneous preterm birth. METHODS: This retrospective population based cohort study included patients who delivered after a primary cesarean section (n = 9983). The rate of placenta previa, its recurrence, and the risk for recurrent preterm birth were determined. RESULTS: Patients who had a placenta previa at the primary CS pregnancy had an increased risk for its recurrence [crude OR of 2.65 (95 % CI 1.3-5.5)]. The rate of preterm birth in patients with placenta previa in the primary CS pregnancy was 55.9 %; and these patients had a higher rate of recurrent preterm delivery than the rest of the study population (p < .001). Among patients with placenta previa in the primary CS pregnancy, those who delivered preterm had a higher rate of recurrent spontaneous preterm birth regardless of the location of their placenta in the subsequent delivery [OR 3.09 (95 % CI 2.1-4.6)]. In comparison to all patients with who had a primary cesarean section, patients who had placenta previa and delivered preterm had an independent increased risk for recurrent preterm birth [OR of 3.6 (95 % CI 1.52-8.51)]. CONCLUSIONS: Women with placenta previa, who deliver preterm, especially before 34 weeks of gestation, are at increased risk for recurrent spontaneous preterm birth regardless to the site of placental implantation in the subsequent pregnancy. Thus, strict follow up by high risk pregnancies specialist is recommended.     

Association of vasa previa at delivery with a history of second-trimester placenta previa

OBJECTIVE: To evaluate whether vasa previa at delivery is associated with a history of second-trimester placenta previa. STUDY DESIGN: Retrospective, case-control study of all vasa previa cases at Good Samaritan Regional Medical Center from January 1, 1991, to May 1, 2001. Cases were identified by ICD-9 codes and confirmed by chart review. Each case was matched in a 1:4 ratio with controls based upon normal placentation at delivery, ultrasound documentation of midtrimester placental location, maternal parity and gestational age at delivery. RESULTS: During the study period, 13 cases of vasa previa were identified. Nine cases (9/13, 69.2%) of vasa previa at delivery had a second-trimester placenta previa as documented by midtrimester ultrasonography, whereas 2 controls (2/52, 3.8%) had a second-trimester placenta previa (P < .000001, OR = 56.3, 95% CI = 8.9-354.1). CONCLUSION: There is a highly significant association between vasa previa at delivery and a history of second-trimester placenta previa.     

Placenta previa and the risk of preterm delivery

Objectives. We aimed to quantify the risk of preterm delivery and maternal and neonatal morbidities associated with placenta previa.

Study design. We conducted a retrospective cohort study of singleton births that occurred between 1976 and 2001, examining outcomes including preterm delivery and perinatal complications. Multivariate logistic regression was used to control for potential confounders. Kaplan–Meier survival curves were constructed to compare preterm delivery in pregnancies complicated by previa vs. no previa.

Results. Among the 38 540 women, 230 women had previas (0.6%). Compared to controls, pregnancies with previa were significantly associated with preterm delivery prior to 28 weeks (3.5% vs. 1.3%; p = 0.003), 32 weeks (11.7% vs. 2.5%; p < 0.001), and 34 weeks (16.1% vs. 3.0%; p < 0.001) of gestation. Patients with previa were more likely to be diagnosed with postpartum hemorrhage (59.7% vs. 17.3%; p < 0.001) and to receive a blood transfusion (11.8% vs. 1.1%; p < 0.001). Survival curves demonstrate the risk of preterm delivery at each week and showed an overall higher rate of preterm delivery for patients with a placenta previa.

Conclusions. Placenta previa is associated with maternal and neonatal complications, including preterm delivery and postpartum hemorrhage. These specific outcomes can be used to counsel women with previa.     

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.     

Placenta previa associated with severe bleeding leading to hospitalization and delivery: a retrospective population-based cohort study

Introduction: The aim of our study was to compare maternal and neonatal outcomes in women with placenta previa complicated with severe bleeding leading to hospitalization until delivery versus those without severe bleeding episodes.

Methods: This is a population-based retrospective cohort study including all pregnant women with placenta previa who delivered at our medical center in the study period, divided into the following groups: 1) women with severe bleeding leading to hospitalization resulting with delivery (n?=?32); 2) patients with placenta previa without severe bleeding episodes (n?=?1217).

Results: Out of all women with placenta previa who delivered at our medical center, 2.6% (32/1249) had an episode of severe bleeding leading to hospitalization and resulting with delivery. The rate of anemia was lower (43.8% versus 63.7%, p?=?0.02) while the need for blood transfusion higher (37.5% versus 21.1%, p?=?0.03) in the study group. The rate of cesarean sections was significantly different between the groups, and a logistic regression model was constructed in order to find independent risk factors for cesarean section in our patients.

Conclusion: To the best of our knowledge, this is the first study to evaluate the impact of severe bleeding on the outcome of pregnancies complicated with placenta previa. Our study demonstrates that, in women with placenta previa, severe bleeding does not lead to increased adverse maternal or neonatal outcomes.     

Random placenta margin incision for control hemorrhage during cesarean delivery complicated by complete placenta previa: a prospective cohort study

Introduction: Complete placenta previa (CPP) is one of the most problematic types of abnormal placenta, which is further complicated by placenta accreta or percreta that can unexpectedly lead to catastrophic blood loss, infection, multiple complications, emergency hysterectomy, and even death. The present study aimed to assess the efficacy of random placenta margin incision in controlling intraoperative and total blood loss during cesarean section for CPP women.

Methods: A prospective cohort study, including a total of 100 consecutive pregnant women with CPP, was performed at a tertiary university-affiliated medical center between March 2016 and July 2017. All of them underwent random placenta margin incision, and intraoperative and total blood loss were analyzed. Through antenatal diagnosis using color Doppler, women were further divided into abnormally invasive placenta (AIP) and non-AIP groups, and anterior and posterior placenta groups. The protocol was registered with the Clinical Trial Registry under registration number NCT02695069.

Results: Mean maternal age and gestational age at delivery were 32.26?±?5.03 years old and 36.21?±?2.07 weeks, respectively. Total duration of the surgical procedure time was 52.50 (42.43–64.00) min. Median estimated intraoperation blood loss was 746.43 (544.44–1092.86) ml. Total blood loss was 875.00 (604.50–1196.67) ml, and 38 (38.0%) had post-partum hemorrhage. The change from baseline in the median hemoglobin level was ?0.33 (6.00–13.20). No women underwent hysterectomy due to massive hemorrhage during the study period. No women had an intraoperative urinary bladder injury, postoperative wound infection, and required relaparotomy, owing to intra-abdominal bleeding. The median hospitalization time was 5.41 (4.18–7.58) d.

Conclusion: The random placenta margin incision may be a potentially valuable surgical procedure to control the volumes of intraoperative and postoperative blood loss and reduce the incidence of postpartum hemorrhage among women with complete placenta previa.     

Cesarean delivery for suspected fetal distress among preterm parturients

OBJECTIVE: Among preterm parturients (< 37 weeks) who underwent cesarean delivery for suspected fetal distress, to determine the factors associated with decision-incision time (DIT) of < or = 30 minutes and to assess if umbilical arterial pH < 7.10 is more common with DIT < or = 30 or > 30 minutes. STUDY DESIGN: The peripartum course of all patients who had cesareans for suspected fetal distress over three years was reviewed. The inclusion criteria were reliable gestational age < 37 weeks and a single indication for cesarean delivery, suspected fetal distress. Twenty antepartum and intrapartum factors were used in a univariate analysis. RESULTS: The mean DIT among the 84 parturients was 30.5 +/- 21.2 minutes, and 63% of patients had surgery started within 30 minutes. The incidence of pH < 7.10 was 20%. Multivariate analysis indicated that the two factors significantly associated with prolonged time to surgery were tachycardia with decreased variability (odds ratio [OR] 5.9, 95% confidence interval [CI] 1.6-21.6) and use of spinal anesthesia (OR 6.2, 95% CI 1.1-35.0). Though none of the 20 variables had significant univariate associations with neonatal acidosis at alpha = .05, those with P < .20 were considered in multiple logistic regression analysis. None of the 20 factors were associated with pH < 7.10, including DIT of > or = 30 minutes (OR 0.26, 95% CI 0.06-1.03). CONCLUSION: DIT is likely to be > 30 minutes if cesarean delivery is due to decreased fetal heart variability or if spinal anesthesia is utilized; neonatal acidosis, however, is not significantly associated with a prolonged interval.     

Placenta previa, placenta accreta, and vasa previa

Placenta previa, placenta accreta, and vasa previa are important causes of bleeding in the second half of pregnancy and in labor. Risk factors for placenta previa include prior cesarean delivery, pregnancy termination, intrauterine surgery, smoking, multifetal gestation, increasing parity, and maternal age. The diagnostic modality of choice for placenta previa is transvaginal ultrasonography, and women with a complete placenta previa should be delivered by cesarean. Small studies suggest that, when the placenta to cervical os distance is greater than 2 cm, women may safely have a vaginal delivery. Regional anesthesia for cesarean delivery in women with placenta previa is safe. Delivery should take place at an institution with adequate blood banking facilities. The incidence of placenta accreta is rising, primarily because of the rise in cesarean delivery rates. This condition can be associated with massive blood loss at delivery. Prenatal diagnosis by imaging, followed by planning of peripartum management by a multidisciplinary team, may help reduce morbidity and mortality. Women known to have placenta accreta should be delivered by cesarean, and no attempt should be made to separate the placenta at the time of delivery. The majority of women with significant degrees of placenta accreta will require a hysterectomy. Although successful conservative management has been described, there are currently insufficient data to recommend this approach to management routinely. Vasa previa carries a risk of fetal exsanguination and death when the membranes rupture. The condition can be diagnosed prenatally by ultrasound examination. Good outcomes depend on prenatal diagnosis and cesarean delivery before the membranes rupture.