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Placenta Previa

Kidney, Urology and Women's Health · NLM MeSH · updated 2026-11-04 · version 1

Citations verified against PubMedNot yet clinician-reviewed10 referencesApproximately 5 min read

Abnormal placentation in which the placenta implants in the lower segment of the uterus (the zone of dilation) and may cover part or all of the opening of the cervix.

Table of Contents

1. Definition2. Research landscape3. Reading the evidence4. Open-access studies5. Key reviews6. References7. About this article

Definition and research guide

This page combines a MeSH definition, publication statistics and selected research abstracts. It is a starting point for reading the literature, not a medical textbook or a systematic evidence review.

Content available: 4 complete abstracts (1,007 words), 10 references. Full article text is not stored or reproduced here; follow the PMID, DOI or PMC links to read the original sources and their access terms.

Definition

Abnormal placentation in which the placenta implants in the lower segment of the uterus (the zone of dilation) and may cover part or all of the opening of the cervix. It is often associated with serious antepartum bleeding and premature labor.

Definition: NLM Medical Subject Headings (MeSH) scope note (Public domain (U.S. National Library of Medicine); attribution requested). View the MeSH record.

Also known as: Placenta Praevia.

Where it fits in the MeSH classification

Broader topics
Obstetric Labor Complications; Placenta Diseases

Related concepts

  • Placenta
  • Uterus
  • Cervix Uteri
  • Premature Labor

Research landscape

PubMed indexes 3,675 records tagged with the MeSH heading “Placenta Previa” (counts retrieved 2026-11-04). 755 of them (20.5%) were published from 2020 onward, and the busiest period so far is through 1999 with 1,749 records.

Reviews account for 265 records (7.2%) and meta-analyses for 57. Randomized controlled trials number 26 (0.7%) as a share of all records on the topic. Randomized trials make up only a small share of this literature, so much of what is known comes from laboratory, observational or descriptive work.

PubMed records by publication periodthrough 1999: 1,749 records; 2000-2009: 344 records; 2010-2019: 827 records; 2020 onward: 755 records1,749through 19993442000-20098272010-20197552020 onward
Records in PubMed indexed with this heading, by publication period. Real counts from NCBI E-utilities; the final period covers only part of the current year. Volume reflects how much has been published, not how strong the evidence is.
Show the data
PeriodRecords
through 19991,749
2000-2009344
2010-2019827
2020 onward755
Share of records by publication typeReviews: 7.2 percent; Meta-analyses: 1.6 percent; Randomized controlled trials: 0.7 percentReviews7.2% (265)Meta-analyses1.6% (57)Randomized controlled trials0.7% (26)
Share of all PubMed records on this heading that carry each publication type. Types overlap with other records, so the shares do not sum to 100%.
Publication-type chart data
Publication types among 3,675 PubMed records
TypeRecordsShare
Reviews2657.2%
Meta-analyses571.6%
Randomized controlled trials260.7%

Method: PubMed query "Placenta Previa"[MeSH Terms] with publication-type and date filters, retrieved 2026-11-04.

Reading the evidence in kidney, urology and women's health

Kidney, urinary and reproductive health research uses lab markers (such as creatinine), imaging, symptom scores and registry data on pregnancy and birth. Findings about pregnancy are especially sensitive to who was studied and when in pregnancy exposure occurred. Nothing on this page is advice about treatment, fertility or pregnancy; speak to a qualified clinician. Check the population, the outcome measured and whether the study accounted for other health differences between groups.

Evidence from open-access studies

These open-access studies come from PubMed’s best-match results for this heading (papers whose main topic it is), ranked here by citation count, with one recent addition. Each abstract is reproduced in full under its recorded open licence so that you can read the authors’ own words. They illustrate the literature; they are not a systematic summary of it. Citation counts measure attention, not reliability or clinical benefit.

Study comparison — selected abstracts, not a systematic review
Study / authorsYearSource label / designEurope PMC citationsLicence / source
Impact of aging on obstetric outcomes: defining advanced maternal age in Barcelona
Claramonte Nieto M, Meler Barrabes E, Garcia Martínez S, Gutiérrez Prat M, Serra Zantop B
2019Research article
Design not recorded in structured metadata
71cc by
PMID 31547808 · DOI · PMC6757376
Association of Placenta Previa With Severe Maternal Morbidity Among Patients With Placenta Accreta Spectrum Disorder
Han X, Guo Z, Yang X, Yang H, Ma J
2022Research article
Design not recorded in structured metadata
34cc by
PMID 35994286 · DOI · PMC9396360
Adverse effects of endometriosis on pregnancy: a case-control study
Miura M, Ushida T, Imai K, Wang J, Moriyama Y, Nakano-Kobayashi T, et al.
2019Research article
Design not recorded in structured metadata
30cc by
PMID 31640604 · DOI · PMC6805464
Intraoperative Transvaginal Ultrasonographic Evaluation for Placenta Accreta Spectrum in Placenta Previa: A Retrospective Observational Study
Mitoma T, Sakata S, Suemori A, Ooba H, Hayata K, Maki J
2026Research article
Design not recorded in structured metadata
1cc by
PMID 42244252 · DOI · PMC13238295

Impact of aging on obstetric outcomes: defining advanced maternal age in Barcelona [1]

Research article Claramonte Nieto M, Meler Barrabes E, Garcia Martínez S, Gutiérrez Prat M, Serra Zantop B · · 2019 · cited 71 times (Europe PMC)

Abstract reading summary — source excerpts
Opening excerpt
BackgroundWomen of advanced maternal age (AMA) are a growing population, with higher obstetric risks.
Closing excerpt
Age ≥ 40 years was associated to relevant increased risks and reveals to be an adequate cut-off to define AMA in our population.
Interpretation limits
Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (208 words)

BackgroundWomen of advanced maternal age (AMA) are a growing population, with higher obstetric risks. The Mediterranean population has specific characteristics different from other areas. Thus, the objective of this study was to establish a cut-off to define AMA in a selected mediterranean population coming from a tertiary referral private/mutual health hospital in Barcelona.MethodsRetrospective cohort of euploid singleton pregnancies delivered from January 2007 to June 2017. Main maternal outcomes were: gestational diabetes, preeclampsia, placenta previa, c-section and prolonged hospitalization (≥ 7 days). Main adverse perinatal outcomes were: stillbirth, prematurity, preterm prelabor rupture of membranes, low birth weight, need of admission at a neonatal intensive care unit and perinatal mortality. Adjustment for confounding factors (smoking, previous comorbilities, parity, assisted reproductive techniques (ART) and obesity) was performed.ResultsA total of 25054 pregnancies were included. Mean maternal age was 34.7 ± 4.2 years, with 2807 patients in the group of age between 40 and 44 years (11.2%) and 280 patients ≥45 years (1.1%). Women at AMA had higher incidence of previous comorbilities (compared to the reference group of women ConclusionsMaternal age is an independent risk factor for adverse obstetric outcomes. Age ≥ 40 years was associated to relevant increased risks and reveals to be an adequate cut-off to define AMA in our population.

Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 31547808 · DOI · PMC6757376

Association of Placenta Previa With Severe Maternal Morbidity Among Patients With Placenta Accreta Spectrum Disorder [2]

Research article Han X, Guo Z, Yang X, Yang H, Ma J · · 2022 · cited 34 times (Europe PMC)

Abstract reading summary — source excerpts
Opening excerpt
ImportancePlacenta previa is widely acknowledged as a risk factor for placenta accreta spectrum (PAS) disorders, which are severe maternal complications; however, data are limited regarding whether placenta previa is associated with a higher risk of worse maternal outcomes among patients with PAS disorders.
Closing excerpt
These findings suggest that interventions to alleviate maternal and surgical morbidities are especially needed for patients with placenta previa-complicated PAS disorders.
Interpretation limits
Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (318 words)

ImportancePlacenta previa is widely acknowledged as a risk factor for placenta accreta spectrum (PAS) disorders, which are severe maternal complications; however, data are limited regarding whether placenta previa is associated with a higher risk of worse maternal outcomes among patients with PAS disorders.ObjectiveTo examine the association between placenta previa and the risk of severe maternal morbidities (SMMs) and higher resource use among patients with PAS disorders.Design, setting, and participantsThis retrospective cohort study extracted records of 3793 patients with PAS diagnosis and delivery indicators between October 1, 2015, and December 31, 2019, from the US National Inpatient Sample database.ExposuresPlacenta previa.Main outcomes and measuresData on 21 Centers for Disease Control and Prevention-defined SMMs and 25 study-defined surgical morbidities associated with PAS were extracted. Six surgical procedures (cystoscopy, intra-arterial balloon occlusion, cesarean delivery, hysterectomy, cystectomy, and oophorectomy), hospital length of stay, and inpatient costs were compared. Multivariable Poisson regression models built in the generalized estimating equation framework were used.ResultsAmong 3793 patients with PAS (median [IQR] age at admission, 33 [29-37] years), 621 women (16.4%) were Black, 765 (20.2%) were Hispanic, 1779 (46.9%) were White, 441 (11.6%) were of other races and/or ethnicities (47 [1.2%] were American Indian, 220 [5.8%] were Asian or Pacific Islander, and 174 [4.6%] were of multiple or other races and/or ethnicities), and 187 (4.9%) were of unknown race and ethnicity. A total of 1323 patients (34.9%) had placenta previa and 2470 patients (65.1%) did not; of those with placenta previa, 405 patients (30.6%) had invasive PAS. Patients with vs without placenta previa had a significantly higher rate and risk of any SMM (935 women [70.7%] vs 1087 women [44.0%]; P Conclusions and relevanceIn this study, placenta previa was associated with an increased risk of maternal and surgical morbidities and higher resource use among women with PAS. These findings suggest that interventions to alleviate maternal and surgical morbidities are especially needed for patients with placenta previa-complicated PAS disorders.

Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 35994286 · DOI · PMC9396360

Adverse effects of endometriosis on pregnancy: a case-control study [3]

Research article Miura M, Ushida T, Imai K, Wang J, Moriyama Y, Nakano-Kobayashi T, et al. · · 2019 · cited 30 times (Europe PMC)

Abstract reading summary — source excerpts
Opening excerpt
BackgroundEndometriosis is a common disease occurring in 1-2% of all women of reproductive age.
Closing excerpt
However, clinicians should be alert to this potential increased risk and manage these patients accordingly.
Interpretation limits
Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (233 words)

BackgroundEndometriosis is a common disease occurring in 1-2% of all women of reproductive age. Although there is increasing evidence on the association between endometriosis and adverse perinatal outcomes, little is known about the effect of pre-pregnancy treatments for endometriosis on subsequent perinatal outcomes. Thus, this study aimed to evaluate maternal and neonatal outcomes in pregnant women with endometriosis and to investigate whether pre-pregnancy surgical treatment would affect these outcomes.MethodsThis case-control study included 2769 patients who gave birth at Nagoya University Hospital located in Japan between 2010 and 2017. Maternal and neonatal outcomes were compared between the endometriosis group (n = 80) and the control group (n = 2689). The endometriosis group was further divided into two groups: patients with a history of surgical treatment such as cystectomy for ovarian endometriosis, ablation or excision of endometriotic implants, or adhesiolysis (surgical treatment group, n = 49) and those treated with only medications or without any treatment (non-surgical treatment group, n = 31).ResultsIn the univariate analysis, placenta previa and postpartum hemorrhage were significantly increased in the endometriosis group compared to the control group (12.5% vs. 4.1%, p ConclusionWomen who have had surgical treatment for their endometriosis appear to have a higher risk for placenta previa. This may be due to the more severe stage of endometriosis often found in these patients. However, clinicians should be alert to this potential increased risk and manage these patients accordingly.

Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 31640604 · DOI · PMC6805464

Intraoperative Transvaginal Ultrasonographic Evaluation for Placenta Accreta Spectrum in Placenta Previa: A Retrospective Observational Study [4]

Research article Mitoma T, Sakata S, Suemori A, Ooba H, Hayata K, Maki J · · 2026 · cited 1 times (Europe PMC)

Abstract reading summary — source excerpts
Opening excerpt
AimTo assess the utility of intraoperative transvaginal ultrasonography (TVUS) in evaluating the duration of blood flow in cervical hypervascularity as a real time diagnostic marker for placenta accreta spectrum (PAS) in placenta previa.
Closing excerpt
A flow duration of < 7 min may help rule out PAS, while ≥ 14 min may suggest its presence and guide safer intraoperative management.
Interpretation limits
Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (248 words)

AimTo assess the utility of intraoperative transvaginal ultrasonography (TVUS) in evaluating the duration of blood flow in cervical hypervascularity as a real time diagnostic marker for placenta accreta spectrum (PAS) in placenta previa.MethodsThis single-center historical cohort study included patients with placenta previa with intraoperative TVUS. The primary outcome was blood flow persistence time, defined as the interval from fetal delivery to disappearance of low-velocity (≤ 2.0 cm/s) color Doppler signals in cervical hypervascularity. Two obstetricians independently reviewed surgical video recordings. Receiver operating characteristic curve analysis was performed to evaluate the diagnostic performance of flow persistence time for predicting PAS. The AUC was calculated to assess discrimination. Optimal cutoffs were based on sensitivity and specificity. Independent predictors of PAS were identified by multivariate regression.ResultsPAS was diagnosed in 20 cases (38.5%). Flow persistence time was significantly longer in PAS cases (20.20 ± 14.31 min) than in non-PAS cases (5.69 ± 2.46 min). A cut-off of 7 min achieved 100% sensitivity and 72% specificity (AUC = 0.94), reliably excluding PAS when flow ceased within this period. A threshold of ≥ 14 min yielded 100% positive predictive value for PAS and 96% specificity for predicting hysterectomy. Flow duration remained an independent predictor in multivariable analysis (AUC = 0.95).ConclusionsIntraoperative assessment of cervical hypervascularity blood flow duration using TVUS may serve as a supportive indicator when PAS is suspected. A flow duration of < 7 min may help rule out PAS, while ≥ 14 min may suggest its presence and guide safer intraoperative management.

Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 42244252 · DOI · PMC13238295

Key reviews and meta-analyses

The most cited review-type papers among PubMed’s best-match results for this heading, listed with bibliographic details only. Follow the links for the full text and access terms.

  • Research article Placenta previa, placenta accreta, and vasa previa [5]
    Oyelese Y, Smulian JC · Obstet Gynecol · 2006 · cited 521 times (Europe PMC)
  • Research article Placenta Praevia and Placenta Accreta: Diagnosis and Management: Green-top Guideline No. 27a [6]
    Jauniaux E, Alfirevic Z, Bhide AG, Belfort MA, Burton GJ, Collins SL, et al. · BJOG · 2019 · cited 348 times (Europe PMC)
  • Research article Abnormal Placentation: Placenta Previa, Vasa Previa, and Placenta Accreta [7]
    Silver RM · Obstet Gynecol · 2015 · cited 292 times (Europe PMC)
  • Research article Effects of smoking during pregnancy. Five meta-analyses [8]
    Castles A, Adams EK, Melvin CL, Kelsch C, Boulton ML · Am J Prev Med · 1999 · cited 271 times (Europe PMC)
  • Research article Prenatal ultrasound diagnosis and outcome of placenta previa accreta after cesarean delivery: a systematic review and meta-analysis [9]
    Jauniaux E, Bhide A · Am J Obstet Gynecol · 2017 · cited 211 times (Europe PMC)
  • Research article The association of placenta previa with history of cesarean delivery and abortion: a metaanalysis [10]
    Ananth CV, Smulian JC, Vintzileos AM · Am J Obstet Gynecol · 1997 · cited 198 times (Europe PMC)

References

  1. Claramonte Nieto M, Meler Barrabes E, Garcia Martínez S, Gutiérrez Prat M, Serra Zantop B. Impact of aging on obstetric outcomes: defining advanced maternal age in Barcelona. . 2019. PMID 31547808 · DOI · PMC6757376
  2. Han X, Guo Z, Yang X, Yang H, Ma J. Association of Placenta Previa With Severe Maternal Morbidity Among Patients With Placenta Accreta Spectrum Disorder. . 2022. PMID 35994286 · DOI · PMC9396360
  3. Miura M, Ushida T, Imai K, Wang J, Moriyama Y, Nakano-Kobayashi T, et al.. Adverse effects of endometriosis on pregnancy: a case-control study. . 2019. PMID 31640604 · DOI · PMC6805464
  4. Mitoma T, Sakata S, Suemori A, Ooba H, Hayata K, Maki J. Intraoperative Transvaginal Ultrasonographic Evaluation for Placenta Accreta Spectrum in Placenta Previa: A Retrospective Observational Study. . 2026. PMID 42244252 · DOI · PMC13238295
  5. Oyelese Y, Smulian JC. Placenta previa, placenta accreta, and vasa previa. Obstet Gynecol. 2006. PMID 16582134 · DOI
  6. Jauniaux E, Alfirevic Z, Bhide AG, Belfort MA, Burton GJ, Collins SL, et al.. Placenta Praevia and Placenta Accreta: Diagnosis and Management: Green-top Guideline No. 27a. BJOG. 2019. PMID 30260097 · DOI
  7. Silver RM. Abnormal Placentation: Placenta Previa, Vasa Previa, and Placenta Accreta. Obstet Gynecol. 2015. PMID 26244528 · DOI
  8. Castles A, Adams EK, Melvin CL, Kelsch C, Boulton ML. Effects of smoking during pregnancy. Five meta-analyses. Am J Prev Med. 1999. PMID 10198660 · DOI
  9. Jauniaux E, Bhide A. Prenatal ultrasound diagnosis and outcome of placenta previa accreta after cesarean delivery: a systematic review and meta-analysis. Am J Obstet Gynecol. 2017. PMID 28268196 · DOI
  10. Ananth CV, Smulian JC, Vintzileos AM. The association of placenta previa with history of cesarean delivery and abortion: a metaanalysis. Am J Obstet Gynecol. 1997. PMID 9396896 · DOI

About this article

Sources
NLM Medical Subject Headings (definition, synonyms); NCBI PubMed (counts, identifiers); Europe PMC (open-access abstracts and citation counts).
Verification
Every reference was resolved against PubMed on 2026-11-04; title, year and DOI matched.
Review state
automated source verified; no human expert review has been recorded yet.
Version
1, last updated 2026-11-04.

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Related research topics

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  • Breech PresentationKidney, Urology and Women's Health
  • Abruptio PlacentaeKidney, Urology and Women's Health
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  • Uterine RuptureKidney, Urology and Women's Health
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All 73 articles in Kidney, Urology and Women's Health →

At a glance

3,675
PubMed records on this heading
21%
published since 2020
265
review articles
26
randomized trials
10
verified references below

Counts come from PubMed on 2026-11-04; they show how much has been written, not how strong the evidence is.

Related topics See all →

  • Uterine InversionKidney, Urology and Women's Health
  • Breech PresentationKidney, Urology and Women's Health
  • Abruptio PlacentaeKidney, Urology and Women's Health
  • Placental InsufficiencyKidney, Urology and Women's Health
  • Uterine RuptureKidney, Urology and Women's Health

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