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Cadernos de Saude Publica Feb 2018This study aimed to investigate the existence and magnitude of the association between advanced maternal age (AMA) and occurrence of placenta praevia (PP) and placental... (Meta-Analysis)
Meta-Analysis Review
This study aimed to investigate the existence and magnitude of the association between advanced maternal age (AMA) and occurrence of placenta praevia (PP) and placental abruption (PA) among nulliparous and multiparous women, by a systematic review and meta-analysis. We searched articles published between January 1, 2005 and December 31, 2015, in any language, in the following databases: PubMed, Scopus, Web of Science, and LILACS. Women were grouped into two age categories: up to 34 years old and 35 years or older. The Newcastle-Ottawa Scale was used to evaluate the methodological quality of the studies. A meta-analysis was conducted for the PP and PA outcomes, using a meta-regression model to find possible covariates associated with heterogeneity among the studies and Egger's test to assess publication bias. The protocol of this systematic review was registered in the International Prospective Register of Systematic Reviews (PROSPERO) system (CRD42016045594). Twenty-three studies met the criteria and were included in the meta-analysis. For both outcomes, an increase in age increased the magnitude of association strength, and PP (OR = 3.16, 95%CI: 2.79-3.57) was more strongly associated with AMA than PA (OR = 1.44, 95%CI: 1.35-1.54). For parity, there was no difference between nulliparous and multiparous women considered older for the PP and PA outcomes. Our review provided very low-quality evidence for both outcomes, since it encompasses observational studies with high statistical heterogeneity, diversity of populations, no control of confounding factors in several cases, and publication bias. However, the confidence intervals were small and there is a dose-response gradient, as well as a large magnitude of effect for PP.
Topics: Abruptio Placentae; Adult; Female; Humans; Maternal Age; Odds Ratio; Parity; Placenta Previa; Pregnancy; Pregnancy Complications; Risk Factors
PubMed: 29489954
DOI: 10.1590/0102-311X00206116 -
PLoS Medicine Jan 2018Cesarean birth rates continue to rise worldwide with recent (2016) reported rates of 24.5% in Western Europe, 32% in North America, and 41% in South America. The... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Cesarean birth rates continue to rise worldwide with recent (2016) reported rates of 24.5% in Western Europe, 32% in North America, and 41% in South America. The objective of this systematic review is to describe the long-term risks and benefits of cesarean delivery for mother, baby, and subsequent pregnancies. The primary maternal outcome was pelvic floor dysfunction, the primary baby outcome was asthma, and the primary subsequent pregnancy outcome was perinatal death.
METHODS AND FINDINGS
Medline, Embase, Cochrane, and Cumulative Index to Nursing and Allied Health Literature (CINAHL) databases were systematically searched for published studies in human subjects (last search 25 May 2017), supplemented by manual searches. Included studies were randomized controlled trials (RCTs) and large (more than 1,000 participants) prospective cohort studies with greater than or equal to one-year follow-up comparing outcomes of women delivering by cesarean delivery and by vaginal delivery. Two assessors screened 30,327 abstracts. Studies were graded for risk of bias by two assessors using the Scottish Intercollegiate Guideline Network (SIGN) Methodology Checklist and the Risk of Bias Assessment tool for Non-Randomized Studies. Results were pooled in fixed effects meta-analyses or in random effects models when significant heterogeneity was present (I2 ≥ 40%). One RCT and 79 cohort studies (all from high income countries) were included, involving 29,928,274 participants. Compared to vaginal delivery, cesarean delivery was associated with decreased risk of urinary incontinence, odds ratio (OR) 0.56 (95% CI 0.47 to 0.66; n = 58,900; 8 studies) and pelvic organ prolapse (OR 0.29, 0.17 to 0.51; n = 39,208; 2 studies). Children delivered by cesarean delivery had increased risk of asthma up to the age of 12 years (OR 1.21, 1.11 to 1.32; n = 887,960; 13 studies) and obesity up to the age of 5 years (OR 1.59, 1.33 to 1.90; n = 64,113; 6 studies). Pregnancy after cesarean delivery was associated with increased risk of miscarriage (OR 1.17, 1.03 to 1.32; n = 151,412; 4 studies) and stillbirth (OR 1.27, 1.15 to 1.40; n = 703,562; 8 studies), but not perinatal mortality (OR 1.11, 0.89 to 1.39; n = 91,429; 2 studies). Pregnancy following cesarean delivery was associated with increased risk of placenta previa (OR 1.74, 1.62 to 1.87; n = 7,101,692; 10 studies), placenta accreta (OR 2.95, 1.32 to 6.60; n = 705,108; 3 studies), and placental abruption (OR 1.38, 1.27 to 1.49; n = 5,667,160; 6 studies). This is a comprehensive review adhering to a registered protocol, and guidelines for the Meta-analysis of Observational Studies in Epidemiology were followed, but it is based on predominantly observational data, and in some meta-analyses, between-study heterogeneity is high; therefore, causation cannot be inferred and the results should be interpreted with caution.
CONCLUSIONS
When compared with vaginal delivery, cesarean delivery is associated with a reduced rate of urinary incontinence and pelvic organ prolapse, but this should be weighed against the association with increased risks for fertility, future pregnancy, and long-term childhood outcomes. This information could be valuable in counselling women on mode of delivery.
Topics: Asthma; Cesarean Section; Female; Humans; Infant; Infant, Newborn; Mothers; Pelvic Floor Disorders; Pregnancy; Pregnancy Outcome; Risk Assessment
PubMed: 29360829
DOI: 10.1371/journal.pmed.1002494 -
Fertility and Sterility Oct 2017To evaluate the effect of endometriosis on pregnancy outcomes. (Meta-Analysis)
Meta-Analysis Review
OBJECTIVE
To evaluate the effect of endometriosis on pregnancy outcomes.
DESIGN
Systematic review and meta-analysis.
SETTING
Not applicable.
PATIENT(S)
Women with or without endometriosis.
INTERVENTION(S)
Electronic databases searched from their inception until February 2017 with no limit for language and with all cohort studies reporting the incidence of obstetric complications in women with a diagnosis of endometriosis compared with a control group (women without a diagnosis of endometriosis) included.
MEAN OUTCOME MEASURE(S)
Primary outcome of incidence of preterm birth at <37 weeks with meta-analysis performed using the random effects model of DerSimonian and Laird to produce an odds ratio (OR) with 95% confidence interval (CI).
RESULT(S)
Twenty-four studies were analyzed comprising 1,924,114 women. In most of them, the diagnosis of endometriosis was made histologically after surgery. Women with endometriosis had a statistically significantly higher risk of preterm birth (OR 1.63; 95% CI, 1.32-2.01), miscarriage (OR 1.75; 95% CI, 1.29-2.37), placenta previa (OR 3.03; 95% CI, 1.50-6.13), small for gestational age (OR 1.27; 95% CI, 1.03-1.57), and cesarean delivery (OR 1.57; 95% CI, 1.39-1.78) compared with the healthy controls. No differences were found in the incidence of gestational hypertension and preeclampsia.
CONCLUSION(S)
Women with endometriosis have a statistically significantly higher risk of preterm birth, miscarriage, placenta previa, small for gestational age infants, and cesarean delivery.
Topics: Endometriosis; Female; Humans; Incidence; Infant, Newborn; Obstetric Labor Complications; Pregnancy; Pregnancy Complications; Pregnancy Outcome; Reproductive Techniques, Assisted
PubMed: 28874260
DOI: 10.1016/j.fertnstert.2017.07.019 -
American Journal of Obstetrics and... Jul 2017Women with a history of previous cesarean delivery, presenting with a placenta previa, have become the largest group with the highest risk for placenta previa accreta. (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Women with a history of previous cesarean delivery, presenting with a placenta previa, have become the largest group with the highest risk for placenta previa accreta.
OBJECTIVE
The objective of the study was to evaluate the accuracy of ultrasound imaging in the prenatal diagnosis of placenta accreta and the impact of the depth of villous invasion on management in women presenting with placenta previa or low-lying placenta and with 1 or more prior cesarean deliveries.
STUDY DESIGN AND DATA SOURCES
We searched PubMed, Google Scholar, clinicalTrials.gov, and MEDLINE for studies published between 1982 and November 2016.
STUDY ELIGIBILITY CRITERIA
Criteria for the study were cohort studies that provided data on previous mode of delivery, placenta previa, or low-lying placenta on prenatal ultrasound imaging and pregnancy outcome. The initial search identified 171 records, of which 5 retrospective and 9 prospective cohort studies were eligible for inclusion in the quantitative analysis.
STUDY APPRAISAL AND SYNTHESIS METHODS
The studies were scored on methodological quality using the Quality Assessment of Diagnostic Accuracy Studies tool.
RESULTS
The 14 cohort studies included 3889 pregnancies presenting with placenta previa or low-lying placenta and 1 or more prior cesarean deliveries screened for placenta accreta. There were 328 cases of placenta previa accreta (8.4%), of which 298 (90.9%) were diagnosed prenatally by ultrasound. The incidence of placenta previa accreta was 4.1% in women with 1 prior cesarean and 13.3% in women with ≥2 previous cesarean deliveries. The pooled performance of ultrasound for the antenatal detection of placenta previa accreta was higher in prospective than retrospective studies, with a diagnostic odds ratios of 228.5 (95% confidence interval, 67.2-776.9) and 80.8 (95% confidence interval, 13.0-501.4), respectively. Only 2 studies provided detailed data on the relationship between the depth of villous invasion and the number of previous cesarean deliveries, independently of the depth of the villous invasion. A cesarean hysterectomy was performed in 208 of 232 cases (89.7%) for which detailed data on management were available. Positive correlations were found in the largest prospective studies between the cumulative rates of the more invasive forms of accreta placentation and the sensitivity and specificity of ultrasound imaging but not with diagnostic odds ratio values. We found no data on the ultrasound screening of placenta accreta at the routine midtrimester ultrasound examination from the nonexpert ultrasound units.
CONCLUSION
Planning individual management for delivery is possible only with accurate evaluation of prenatal risk of accreta placentation in women presenting with a low-lying placenta/previa and a history of prior cesarean delivery. Ultrasound is highly sensitive and specific in the prenatal diagnosis of accreta placentation when performed by skilled operators. Developing a prenatal screening protocol is now essential to further improve the outcome of this increasingly more common major obstetric complication.
Topics: Cesarean Section; Female; Humans; Hysterectomy; MEDLINE; Placenta Accreta; Placenta Previa; Placentation; Pregnancy; Pregnancy Outcome; Prospective Studies; Retrospective Studies; Risk Factors; Sensitivity and Specificity; Ultrasonography, Prenatal
PubMed: 28268196
DOI: 10.1016/j.ajog.2017.02.050 -
PloS One 2017The global burden of postpartum hemorrhage (PPH) in women with placenta previa is a major public health concern. Although there are different reports on the incidence of... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
The global burden of postpartum hemorrhage (PPH) in women with placenta previa is a major public health concern. Although there are different reports on the incidence of PPH in different countries, to date, no research has reviewed them.
OBJECTIVE
The aim of this study was to calculate the average point incidence of PPH in women with placenta previa.
METHODS
A systematic review and meta-analysis of observational studies estimating PPH in women with placenta previa was conducted through literature searches in four databases in Jul 2016. This study was totally conducted according to the MOOSE guidelines and in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses standard.
RESULTS
From 1148 obtained studies, 11 included in the meta-analysis, which involved 5146 unique pregnant women with placenta previa. The overall pooled incidence of PPH was 22.3% (95% CI 15.8-28.7%). In the subgroup, the prevalence was 27.4% in placenta previas, and was 14.5% in low-lying placenta previa; the highest prevalence was estimated in Northern America (26.3%, 95%CI 11.0-41.6%), followed by the Asia (20.7%, 95%CI 12.8-28.6%), Australia (19.2%, 95% CI 17.2-21.1%) and Europe (17.8%, 95% CI, 11.5%-24.0%).
CONCLUSIONS
The summary estimate of the incidence of PPH among women with placenta previa was considerable in this systematic review. The results will be crucial in prevention, treatment, and identification of PPH among pregnant women with placenta previa and will be contributed to the planning and implantation of relevant public health strategies.
Topics: Adult; Female; Humans; Incidence; Placenta Previa; Postpartum Hemorrhage; Pregnancy
PubMed: 28107460
DOI: 10.1371/journal.pone.0170194 -
Scientific Reports Jan 2017Antepartum hemorrhage (APH) is an important cause of perinatal mortality and maternal morbidity in pregnant women with placenta previa in the world. However, the... (Meta-Analysis)
Meta-Analysis Review
Antepartum hemorrhage (APH) is an important cause of perinatal mortality and maternal morbidity in pregnant women with placenta previa in the world. However, the epidemiological characteristics are not completely understood. We performed an initial systematic review and meta-analysis to assess the prevalence of APH in pregnant women with placenta previa. It was totally performed following the Preferred Reporting Items for Systematic reviews and Meta-Analysis statement. PubMed, Elsevier Science Direct, and the Cochrane Library were searched before April 2016. A meta-analysis with a random-effects model based on a proportions approach was performed to determine the prevalence. Stratified analyses, meta-regression method, and sensitivity analysis were utilized to analyze the heterogeneity. A total of 29 articles were included. The pooled overall prevalence of APH among pregnant women with placenta previa was 51.6% (95% CI 42.7-60.6) in a heterogeneous set of studies (I = 97.9). Correlation analysis found that there was a positive correlation between prevalence and percentage of multiparous (r = 0.534, P = 0.027) and a negative correlation between prevalence and survey year (r = -0.400, P = 0.031). In conclusion, the prevalence of APH was a high condition among pregnant women with placenta previa.
Topics: Adult; Female; Humans; Parity; Placenta Previa; Pregnancy; Prevalence; Regression Analysis; Uterine Hemorrhage
PubMed: 28067303
DOI: 10.1038/srep40320 -
Medicine Oct 2016Placenta previa is characterized by the abnormal placenta overlying the endocervical os, and it is known as one of the most feared adverse maternal and fetal-neonatal... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Placenta previa is characterized by the abnormal placenta overlying the endocervical os, and it is known as one of the most feared adverse maternal and fetal-neonatal complications in obstetrics.
OBJECTIVES
We aimed to obtain overall and regional estimates of placenta previa prevalence among deliveries in Mainland China.
METHODS
The research was performed a systematic review, following the Meta-analysis of observational studies in epidemiology (MOOSE) guidelines for systematic reviews of observational studies, and the preferred reporting items for systematic reviews and meta-analysis (PRISMA) statement for reporting systematic reviews and meta-analysis. Electronic databases were searched and included hospital-based studies that reported placenta previa prevalence in Mainland China. Random-effects meta-analyses were used to pool prevalence estimates of placenta previa. Meta-regression analyses were performed to explore sources of heterogeneity across the included studies. For exploring the geographical distributions of placenta previa, the ArcGIS software (Esri) was used to construct the map of prevalence.
RESULTS
A total of 80 articles and 86 datasets (including 1,298,548 subjects and 14,199 placenta previa cases) from 1965 through 2015 were included. The pooled overall prevalence of placenta previa among deliveries was 1.24% (95% confidence interval [CI], 1.12-1.36) in Mainland China during 1965 to 2015. And, the trend in the prevalence of placenta previa was steady. The occurrence rate of placenta previa in the region groups Northeast, North, Northwest, Central China, East, South, and Southwest was 1.20%, 1.01%, 1.10%, 1.15%, 0.93%, 1.42%, and 2.01%, respectively. The prevalence map based on a geographic information system showed an unequal geographic distribution.
CONCLUSIONS
The results showed that placenta previa is currently a high-burden disease in Mainland China. This review would be useful for the design of placenta previa planning and implementation adequate health care systems and treatment programs in Mainland China.
Topics: China; Delivery, Obstetric; Female; Humans; Placenta Previa; Pregnancy; Prevalence
PubMed: 27749592
DOI: 10.1097/MD.0000000000005107 -
Fertility and Sterility May 2016To examine whether dichorionic twin pregnancies after assisted reproductive technology (ART) were at higher risk of adverse obstetric outcomes compared with those... (Meta-Analysis)
Meta-Analysis Review
OBJECTIVE
To examine whether dichorionic twin pregnancies after assisted reproductive technology (ART) were at higher risk of adverse obstetric outcomes compared with those conceived naturally.
DESIGN
Meta-analysis.
SETTING
University-affiliated teaching hospital.
PATIENT(S)
Dichorionic twin pregnancies conceived with ART and naturally.
INTERVENTION(S)
Studies comparing obstetric outcomes in dichorionic twin pregnancies conceived by ART and naturally were identified by searching PubMed, Google Scholar, Cochrane Libraries, and Chinese databases through July 2015 with no restrictions. Either a fixed-effects or a random-effects model was used to calculate the overall combined risk estimates. Subgroup analysis was performed to explore potential heterogeneity moderators.
MAIN OUTCOME MEASURE(S)
Maternal complications and adverse pregnancy outcomes.
RESULT(S)
Fifteen cohort studies involving 6,420 dichorionic twins after ART and 13,650 dichorionic twins conceived naturally were included. Most of maternal complications were similar in both groups, but placenta previa (relative risk [RR] = 2.99, 95% confidence interval [CI] 1.51-5.92; I(2) = 0) was significantly more common in the ART group. For neonatal outcomes, the ART group experienced higher risk of preterm birth (RR = 1.13, 95% CI 1.00-1.29; I(2) = 75%), very preterm birth (RR = 1.39, 95% CI 1.07-1.82; I(2) = 71%), low birth weight (RR = 1.11, 95% CI 1.00-1.23; I(2) = 61%), and congenital malformations (RR = 1.26, 95% CI 1.09-1.46; I(2) = 26%). In addition, the ART group had a higher proportion of elective cesarean sections (RR = 1.79, 95% CI 1.49-2.16; I(2) = 60%), but had a similar proportion for emergency cesarean sections. Relevant heterogeneity moderators have been identified by subgroup analysis. No evidence of publication bias was observed.
CONCLUSION(S)
The rates of placenta previa, elective cesarean section, preterm birth, very preterm birth, low birth weight, and congenital malformations were significantly higher in dichorionic twin pregnancies after ART.
Topics: Chorion; Delivery, Obstetric; Female; Humans; Pregnancy; Pregnancy Complications; Pregnancy Outcome; Pregnancy, Twin; Reproductive Techniques, Assisted
PubMed: 26801066
DOI: 10.1016/j.fertnstert.2015.12.131 -
Taiwanese Journal of Obstetrics &... Dec 2015To determine factors associated with late preterm births in an underdeveloped region of China, and search for relevant reports in other underdeveloped regions by a... (Review)
Review
OBJECTIVE
To determine factors associated with late preterm births in an underdeveloped region of China, and search for relevant reports in other underdeveloped regions by a systematic review.
MATERIALS AND METHODS
Data of births occurring between January 2004 and December 2008 from eight hospitals in Western Sichuan Province, China, were analyzed. Late preterm birth was defined as delivery at 34-36 6/7 weeks' gestation. Medline, Cochrane Library, and Google Scholar were searched for studies which reported the risk factors of late preterm births in undeveloped regions until January 31, 2014.
RESULTS
During the study period there were 4711 late preterm births and 54,574 term births. The odds ratios (ORs) for a late preterm birth of mothers < 20 years and ≥ 35 years of age were 3.813 [95% confidence interval (CI): 3.256-4.465] and 1.872 (95% CI: 1.677-2.090), respectively, as compared with an age of 20-34.9 years. Mothers who received prenatal care were less likely (OR = 0.623, 95% CI: 0.582-0.667) and those with a multiple gestation were more likely (OR = 9.346, 95% CI: 7.813, 11.236) to have a late preterm birth. The systematic review found that the incidence of late preterm births ranged from 4.4% to 16%, and the most prominent risk factors were eclampsia, preeclampsia, placenta previa, placental abruption, and twin pregnancy.
CONCLUSION
A number of factors are associated with late preterm births, and the incidence in underdeveloped regions is high. The inconsistent results between our study and previous reports indicate more attention towards preventing late preterm births in undeveloped regions is needed.
Topics: Adult; China; Cohort Studies; Delivery, Obstetric; Developing Countries; Female; Gestational Age; Humans; Maternal Age; Pregnancy; Pregnancy Complications; Pregnancy, Multiple; Premature Birth; Retrospective Studies; Risk Factors; Young Adult
PubMed: 26700979
DOI: 10.1016/j.tjog.2014.05.011 -
Ultrasound in Obstetrics & Gynecology :... May 2015Vasa previa is an obstetric complication in which the fetal blood vessels lie outside the chorionic plate in close proximity to the internal cervical os. In women with... (Review)
Review
OBJECTIVE
Vasa previa is an obstetric complication in which the fetal blood vessels lie outside the chorionic plate in close proximity to the internal cervical os. In women with vasa previa, the risk of rupture of these vessels is increased, thus potentially causing fetal death or serious morbidity. Our objective was to assess the accuracy of ultrasound in the prenatal diagnosis of vasa previa.
METHODS
We searched MEDLINE, EMBASE, the Cochrane Library and PubMed for studies on vasa previa. Two reviewers independently selected studies on the accuracy of ultrasound in the diagnosis of vasa previa. The studies were scored on methodological quality using the Quality Assessment of Diagnostic Accuracy Studies tool (QUADAS-2). Data on sensitivity and specificity were subsequently extracted.
RESULTS
The literature search revealed 583 articles, of which two prospective and six retrospective cohort studies were eligible for inclusion in the qualitative analysis. All studies documented methods suitable for the prenatal diagnosis of vasa previa. Four out of the eight studies used transvaginal ultrasound (TVS) for primary evaluation, while the remaining four studies used transabdominal ultrasound and performed a subsequent TVS when vasa previa was suspected. The QUADAS-2 tool reflected poor methodology in six of the eight included studies, and prenatal detection rates varied from 53% (10/19) to 100% (total of 442,633 patients, including 138 cases of vasa previa). In the two prospective studies (n = 33,795, including 11 cases of vasa previa), transvaginal color Doppler performed during the second trimester detected all cases of vasa previa (sensitivity, 100%) with a specificity of 99.0-99.8%.
CONCLUSION
The accuracy of ultrasound in the diagnosis of vasa previa is high when performed transvaginally in combination with color Doppler.
Topics: Adult; Female; Humans; Placenta; Predictive Value of Tests; Pregnancy; Pregnancy Complications; Prospective Studies; Retrospective Studies; Ultrasonography, Doppler, Color; Ultrasonography, Prenatal; Umbilical Cord; Vasa Previa
PubMed: 25491755
DOI: 10.1002/uog.14752