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Journal of Obstetrics and Gynaecology... Jul 2020To summarize the current evidence and to make recommendations for diagnosis and classification of placenta previa and for managing the care of women with this diagnosis.
OBJECTIVES
To summarize the current evidence and to make recommendations for diagnosis and classification of placenta previa and for managing the care of women with this diagnosis.
OPTIONS
To manage in hospital or as an outpatient and to perform a cesarean delivery preterm or at term or to allow a trial of labour when a diagnosis of placenta previa or a low-lying placenta is suspected or confirmed.
OUTCOMES
Prolonged hospitalization, preterm birth, rate of cesarean delivery, maternal morbidity and mortality, and postnatal morbidity and mortality.
INTENDED USERS
Family physicians, obstetricians, midwives, and other maternal care providers.
TARGET POPULATION
Pregnant women with placenta previa or low-lying placenta.
EVIDENCE
Medline, PubMed, Embase, and the Cochrane Library were searched from inception to October 2018. Medical Subject Heading (MeSH) terms and key words related to pregnancy, placenta previa, low-lying placenta, antepartum hemorrhage, short cervical length, preterm labour, and cesarean. This document represents an abstraction of the evidence rather than a methodological review.
VALIDATION METHODS
This guideline has been reviewed by the Maternal-Fetal Medicine and Diagnostic Imaging committees of the Society of Obstetricians and Gynaecologists of Canada (SOGC) and approved by the SOGC Board of Directors.
BENEFITS, HARMS, AND/OR COSTS
Women with placenta previa or low-lying placenta are at increased risk of maternal, fetal and postnatal adverse outcomes that include a potentially incorrect diagnosis and possibly unnecessary hospitalization, restriction of activities, early delivery, or cesarean delivery. Optimization of diagnosis and management protocols has potential to improve maternal, fetal and postnatal outcomes.
SUMMARY STATEMENTS (GRADE RATINGS IN PARENTHESES)
RECOMMENDATIONS (GRADE RATINGS IN PARENTHESES).
Topics: Canada; Cervix Uteri; Cesarean Section; Delivery, Obstetric; Female; Humans; Infant, Newborn; Obstetric Labor, Premature; Placenta Previa; Pregnancy; Pregnancy Complications; Premature Birth
PubMed: 32591150
DOI: 10.1016/j.jogc.2019.07.019 -
BMJ Open Nov 2019To estimate the prevalence and incidence of placenta previa complicated by placenta accreta spectrum (PAS) and to examine the different criteria being used for the... (Meta-Analysis)
Meta-Analysis
OBJECTIVE
To estimate the prevalence and incidence of placenta previa complicated by placenta accreta spectrum (PAS) and to examine the different criteria being used for the diagnosis.
DESIGN
Systematic review and meta-analysis.
DATA SOURCES
PubMed, Google Scholar, ClinicalTrials.gov and MEDLINE were searched between August 1982 and September 2018.
ELIGIBILITY CRITERIA
Studies reporting on placenta previa complicated by PAS diagnosed in a defined obstetric population.
DATA EXTRACTION AND SYNTHESIS
Two independent reviewers performed the data extraction using a predefined protocol and assessed the risk of bias using the Newcastle-Ottawa scale for observational studies, with difference agreed by consensus. The primary outcomes were overall prevalence of placenta previa, incidence of PAS according to the type of placenta previa and the reported clinical outcomes, including the number of peripartum hysterectomies and direct maternal mortality. The secondary outcomes included the criteria used for the prenatal ultrasound diagnosis of placenta previa and the criteria used to diagnose and grade PAS at birth.
RESULTS
A total of 258 articles were reviewed and 13 retrospective and 7 prospective studies were included in the analysis, which reported on 587 women with placenta previa and PAS. The meta-analysis indicated a significant (p<0.001) heterogeneity between study estimates for the prevalence of placenta previa, the prevalence of placenta previa with PAS and the incidence of PAS in the placenta previa cohort. The median prevalence of placenta previa was 0.56% (IQR 0.39-1.24) whereas the median prevalence of placenta previa with PAS was 0.07% (IQR 0.05-0.16). The incidence of PAS in women with a placenta previa was 11.10% (IQR 7.65-17.35).
CONCLUSIONS
The high heterogeneity in qualitative and diagnostic data between studies emphasises the need to implement standardised protocols for the diagnoses of both placenta previa and PAS, including the type of placenta previa and grade of villous invasiveness.
PROSPERO REGISTRATION NUMBER
CRD42017068589.
Topics: Female; Humans; Hysterectomy; Incidence; Peripartum Period; Placenta Accreta; Placenta Previa; Pregnancy; Prevalence; Ultrasonography, Prenatal
PubMed: 31722942
DOI: 10.1136/bmjopen-2019-031193 -
Placenta Jan 2022We evaluated in this umbrella review a systematic collection from meta-analyses conducted on risk factors associated with placenta previa. We searched PubMed, Scopus,... (Review)
Review
We evaluated in this umbrella review a systematic collection from meta-analyses conducted on risk factors associated with placenta previa. We searched PubMed, Scopus, and Web of Science until April 2021 assessing the risk factors associated with placenta previa. We calculated summary effect estimates odds ratio, relative risk, 95% CI, heterogeneity I, 95% prediction interval, small-study effects, excess significance biases, and sensitive analysis. The quality of the meta-analyses was evaluated with AMSTAR 2. We included nine studies in the present umbrella review. Seven risk factors including prior induced abortion (OR 1·36, 95% CI: 1·02, 1·69), prior spontaneous abortion (OR 1·77, 95% CI: 1·60, 1·94), male fetus (OR 1·2, 95% CI: 1·2, 1·3), smoking (OR 1·42, 95% CI 1·30, 1·54) (RR 1·27, 95% CI: 1·18, 1·35) advanced maternal age (OR 3·16, 95% CI: 2·79, 3·57), cesarean (OR 1·60, 95% CI: 1·44, 1·76) and ART (singleton pregnancy) (RR 3·71, 95% CI: 2·67, 5·16) were graded as highly suggestive evidence (class III). Endometriosis (OR 3·03, 95% CI: 1·50, 6·13) and maternal cocaine use (OR 2·9, 95% CI: 1·9, 4·3) were graded as risk factors with weak evidence (class IV). This study provides suggestive evidence about prior spontaneous abortion, prior induced abortion, male fetus, smoking, advanced maternal age, cesarean section, and assisted reproductive techniques (singleton pregnancy) as risk factors associated with placenta previa.
Topics: Female; Humans; Meta-Analysis as Topic; Placenta Previa; Pregnancy; Risk Factors; Systematic Reviews as Topic
PubMed: 34768164
DOI: 10.1016/j.placenta.2021.10.009 -
CMAJ : Canadian Medical Association... Aug 2020
Review
Topics: Cesarean Section; Female; Humans; Hysterectomy; Placenta Accreta; Placenta Previa; Pregnancy; Risk Factors
PubMed: 32839166
DOI: 10.1503/cmaj.200304 -
American Journal of Obstetrics and... Sep 2020The evolution of multidisciplinary team-based care for women with placenta accreta spectrum disorder has delivered stepwise improvements in clinical outcomes. Central to... (Review)
Review
The evolution of multidisciplinary team-based care for women with placenta accreta spectrum disorder has delivered stepwise improvements in clinical outcomes. Central to this overall goal is the ability to limit blood loss at surgery. Placement of inflatable balloons within the pelvic arteries, most commonly in the anterior divisions of the internal iliac arteries, became popular in many centers, at the expense of prolonging surgical care and with attendant risks of vascular injury. In tandem, the need to expose pelvic sidewall anatomy to safely identify the course of the ureters re-popularized the alternative strategy of ligating the same anterior divisions of the internal iliac arteries. With incremental gains in surgical expertise, described in 5 steps in this review, our teams have witnessed a steady decline in surgical blood loss. Nevertheless, a subset of women has the most severe form of placenta accreta spectrum, namely placenta previa-percreta. Such women are at risk of major hemorrhage during surgery from vessels arising outside the territories of the internal iliac arteries. These additional blood supplies, mostly from the external iliac arteries, pose significant risks of major blood loss even in experienced hands. To address this risk, some centers, principally in China, have adopted an approach of routinely placing an infrarenal aortic balloon, with both impressively low rates of blood loss and an ability to conserve the uterus by resecting the placenta with the affected portion of the uterine wall. We review these literature developments in the context of safely performing elective cesarean hysterectomy for placenta previa-percreta, the most severe placenta accreta spectrum disorder.
Topics: Balloon Occlusion; Blood Loss, Surgical; Cesarean Section; Colpotomy; Female; Humans; Hysterectomy; Iliac Artery; Ligation; Magnetic Resonance Imaging; Placenta Accreta; Placenta Previa; Pregnancy; Risk Factors; Treatment Outcome
PubMed: 32007492
DOI: 10.1016/j.ajog.2020.01.044 -
Best Practice & Research. Clinical... Nov 2019The increasing incidence of caesarean delivery (CD) has resulted in an increase in placenta accreta spectrum (PAS), adversely impacting maternal outcomes globally.... (Review)
Review
The increasing incidence of caesarean delivery (CD) has resulted in an increase in placenta accreta spectrum (PAS), adversely impacting maternal outcomes globally. Currently, more than 90% of women diagnosed with PAS present with a placenta praevia (praevia PAS). Praevia PAS can be reliably diagnosed antenatally with ultrasound, and it is unclear whether magnetic resonance imaging improves diagnosis beyond what can be achieved by skilled ultrasound operators. Therefore, any screening programme for PAS will require improved training in the diagnosis of placental disorders and development of targeted scanning protocols. Management strategies for praevia PAS vary depending on the accuracy of prenatal diagnosis, findings at laparotomy and local surgical expertise. Current epidemiological data for PAS are highly heterogeneous, mainly due to wide variation in the clinical criteria used to diagnose the condition at birth. This significantly impacts research into all aspects of the condition, especially comparison of the efficacy of different management strategies.
Topics: Cesarean Section; Female; Humans; Magnetic Resonance Imaging; Placenta Accreta; Placenta Previa; Pregnancy; Prenatal Diagnosis
PubMed: 31126811
DOI: 10.1016/j.bpobgyn.2019.04.006 -
Fertility and Sterility Feb 2020The use of frozen-thawed embryo transfer (FET) has increased over the past decade with improvements in technology and increasing live birth rates. FET facilitates... (Review)
Review
The use of frozen-thawed embryo transfer (FET) has increased over the past decade with improvements in technology and increasing live birth rates. FET facilitates elective single-embryo transfer, reduces ovarian hyperstimulation syndrome, optimizes endometrial receptivity, allows time for preimplantation genetics testing, and facilitates fertility preservation. FET cycles have been associated, however, with an increased risk of hypertensive disorders of pregnancy for reasons that are not clear. Recent evidence suggests that absence of the corpus luteum (CL) could be at least partly responsible for this increased risk. In a recent prospective cohort study, programmed FET cycles (no CL) were associated with higher rates of preeclampsia and preeclampsia with severe features compared with modified natural FET cycles. FET cycles are commonly performed in the context of a programmed cycle in which the endometrium is prepared with the use of exogenous E and P. In these cycles, ovulation is suppressed and therefore the CL is absent. The CL produces not only E and P, but also vasoactive products, such as relaxin and vascular endothelial growth factor, which are not replaced in a programmed FET cycle and which are hypothesized to be important for initial placentation. Emerging evidence has also revealed other adverse obstetrical and perinatal outcomes, including postpartum hemorrhage, macrosomia, and post-term birth specifically in programmed FET cycles compared with natural FET cycles. Despite the widespread use of FET, the optimal protocol with respect to live birth rate, maternal health, and perinatal outcomes has yet to be determined. Future practice regarding FET should be based on high-quality evidence, including rigorous controlled trials.
Topics: Adaptation, Physiological; Corpus Luteum; Cryopreservation; Embryo Transfer; Female; Humans; Infant, Low Birth Weight; Placenta Previa; Pre-Eclampsia; Pregnancy; Pregnancy Outcome
PubMed: 32106972
DOI: 10.1016/j.fertnstert.2019.12.007 -
American Journal of Obstetrics and... Apr 2020To assess the efficacy, effectiveness, and safety of uterine balloon tamponade for treating postpartum hemorrhage. (Meta-Analysis)
Meta-Analysis
OBJECTIVE
To assess the efficacy, effectiveness, and safety of uterine balloon tamponade for treating postpartum hemorrhage.
STUDY DESIGN
We searched electronic databases (from their inception to August 2019) and bibliographies. We included randomized controlled trials, nonrandomized studies, and case series that reported on the efficacy, effectiveness, and/or safety of uterine balloon tamponade in women with postpartum hemorrhage. The primary outcome was the success rate of uterine balloon tamponade for treating postpartum hemorrhage (number of uterine balloon tamponade success cases/total number of women treated with uterine balloon tamponade). For meta-analyses, we calculated pooled success rate for all studies, and relative risk with 95% confidence intervals for studies that included a comparative arm.
RESULTS
Ninety-one studies, including 4729 women, met inclusion criteria (6 randomized trials, 1 cluster randomized trial, 15 nonrandomized studies, and 69 case series). The overall pooled uterine balloon tamponade success rate was 85.9% (95% confidence interval, 83.9-87.9%). The highest success rates corresponded to uterine atony (87.1%) and placenta previa (86.8%), and the lowest to placenta accreta spectrum (66.7%) and retained products of conception (76.8%). The uterine balloon tamponade success rate was lower in cesarean deliveries (81.7%) than in vaginal deliveries (87.0%). A meta-analysis of 2 randomized trials that compared uterine balloon tamponade vs no uterine balloon tamponade in postpartum hemorrhage due to uterine atony after vaginal delivery showed no significant differences between the study groups in the risk of surgical interventions or maternal death (relative risk, 0.59; 95% confidence interval, 0.02-16.69). A meta-analysis of 2 nonrandomized before-and-after studies showed that introduction of uterine balloon tamponade in protocols for managing severe postpartum hemorrhage significantly decreased the use of arterial embolization (relative risk, 0.29; 95% confidence interval, 0.14-0.63). A nonrandomized cluster study reported that use of invasive procedures was significantly lower in the perinatal network that routinely used uterine balloon tamponade than that which did not use uterine balloon tamponade (3.0/1000 vs 5.1/1000; P < .01). A cluster randomized trial reported that the frequency of postpartum hemorrhage-related invasive procedures and/or maternal death was significantly higher after uterine balloon tamponade introduction than before uterine balloon tamponade introduction (11.6/10,000 vs 6.7/10,000; P = .04). Overall, the frequency of complications attributed to uterine balloon tamponade use was low (≤6.5%).
CONCLUSION
Uterine balloon tamponade has a high success rate for treating severe postpartum hemorrhage and appears to be safe. The evidence on uterine balloon tamponade efficacy and effectiveness from randomized and nonrandomized studies is conflicting, with experimental studies suggesting no beneficial effect, in contrast with observational studies. Further research is needed to determine the most effective programmatic and healthcare delivery strategies on uterine balloon tamponade introduction and use.
Topics: Cesarean Section; Female; Humans; Maternal Mortality; Parturition; Placenta Accreta; Placenta Previa; Placenta, Retained; Postpartum Hemorrhage; Pregnancy; Uterine Artery Embolization; Uterine Balloon Tamponade; Uterine Inertia
PubMed: 31917139
DOI: 10.1016/j.ajog.2019.11.1287 -
Best Practice & Research. Clinical... Aug 2023Screening for clinically significant placenta accreta spectrum (PAS) is possible with a high degree of accuracy (both sensitivity and specificity >90-95%). The group of... (Review)
Review
Screening for clinically significant placenta accreta spectrum (PAS) is possible with a high degree of accuracy (both sensitivity and specificity >90-95%). The group of women to focus on are those with placenta previa and one or more prior Cesarean deliveries. Screening for PAS not associated with placenta previa is not as productive, and several false negatives have been described. The results of the screening program indicate that women have a low or high probability of PAS. Screen-positive women or those with uncertain ultrasound features should be referred to a center of excellence. Those confirmed to have a high probability of PAS should electively be delivered at such centers.
Topics: Pregnancy; Female; Humans; Placenta Accreta; Placenta Previa; Retrospective Studies; Cesarean Section; Ultrasonography; Placenta
PubMed: 37541113
DOI: 10.1016/j.bpobgyn.2023.102392 -
American Journal of Obstetrics and... Dec 2020
Topics: Female; Humans; Placenta Accreta; Placenta Previa; Pregnancy
PubMed: 32562658
DOI: 10.1016/j.ajog.2020.06.025