Endometriosis Is Associated with Adverse Pregnancy Outcomes: a National Population-Based Study

Untangling the independent effect of endometriosis, adenomyosis, and ART-related factors on maternal, placental, fetal, and neonatal adverse outcomes: results from a systematic review and meta-analysis

BACKGROUND

Women with endometriosis may constitute a group at a particularly increased risk of pregnancy-related complications. Furthermore, women selected for assisted reproductive technology (ART) are exposed to additional endocrinological and embryological factors that have been associated with adverse pregnancy outcomes.

OBJECTIVE AND RATIONALE

This study aimed to investigate the independent effect of endometriosis, adenomyosis, and various ART-related factors on adverse maternal, placental, fetal, and neonatal outcomes.

SEARCH METHODS

Published randomized controlled trials, cohort studies, and case-control studies were considered eligible. PubMed, MEDLINE, ClinicalTrials.gov, Embase, and Scopus were systematically searched up to 1 March 2024. This systematic review and meta-analysis was performed in line with the PRISMA and the MOOSE reporting guidelines. To thoroughly investigate the association between endometriosis/adenomyosis and adverse pregnancy outcomes, sub-analyses were conducted, whenever possible, according to: the method of conception (i.e. ART and non-ART conception), the endometriosis stage/phenotype, the coexistence of endometriosis and adenomyosis, any pre-pregnancy surgical treatment of endometriosis, and the form of adenomyosis. The odds ratio (OR) with 95% CI was used as effect measure. The quality of evidence was assessed using the GRADE approach.

OUTCOMES

We showed a higher risk of placenta previa in women with endometriosis compared to controls (34 studies, OR 2.84; 95% CI: 2.47, 3.26; I2 = 83%, moderate quality). The association was observed regardless of the method of conception and was particularly strong in the most severe forms of endometriosis (i.e. rASRM stage III-IV endometriosis and deep endometriosis (DE)) (OR 6.61; 95% CI: 2.08, 20.98; I2 = 66% and OR 14.54; 95% CI: 3.67, 57.67; I2 = 54%, respectively). We also showed an association, regardless of the method of conception, between endometriosis and: (i) preterm birth (PTB) (43 studies, OR 1.43; 95% CI: 1.32, 1.56; I2 = 89%, low quality) and (ii) cesarean section (29 studies, OR 1.52; 95% CI: 1.41, 1.63; I2 = 93%, low quality). The most severe forms of endometriosis were strongly associated with PTB. Two outcomes were associated with adenomyosis both in the main analysis and in the sub-analysis that included only ART pregnancies: (i) miscarriage (14 studies, OR 1.83; 95% CI: 1.53, 2.18; I2 = 72%, low quality) and (ii) pre-eclampsia (7 studies, OR 1.70; 95% CI: 1.16, 2.48; I2 = 77%, low quality). Regarding ART-related factors, the following associations were observed in the main analysis and confirmed in all sub-analyses conducted by pooling only risk estimates adjusted for covariates: (i) blastocyst stage embryo transfer (ET) and monozygotic twinning (28 studies, OR 2.05; 95% CI, 1.72, 2.45; I2 = 72%, low quality), (ii) frozen embryo transfer (FET) and (reduced risk of) small for gestational age (21 studies, OR 0.59; 95% CI, 0.57, 0.61; P < 0.00001; I2 = 17%, very low quality) and (increased risk of) large for gestational age (16 studies, OR 1.70; 95% CI, 1.60, 1.80; P < 0.00001; I2 = 55%, very low quality), (iii) artificial cycle (AC)-FET and pre-eclampsia (12 studies, OR 2.14; 95% CI: 1.91-2.39; I2 = 9%, low quality), PTB (21 studies, OR 1.24; 95% CI 1.15, 1.34; P < 0.0001; I2 = 50%, low quality), cesarean section (15 studies, OR 1.59; 95% CI 1.49, 1.70; P < 0.00001; I2 = 67%, very low quality) and post-partum hemorrhage (6 studies, OR 2.43; 95% CI 2.11, 2.81; P < 0.00001; I2 = 15%, very low quality).

WIDER IMPLICATIONS

Severe endometriosis (i.e. rASRM stage III-IV endometriosis, DE) constitutes a considerable risk factor for placenta previa and PTB. Herein, we recommend against superimposing on this condition other exposure factors that have a strong association with the same obstetric adverse outcome or with different outcomes which, if coexisting, could determine the onset of an ominous obstetric syndrome. Specifically, we strongly discourage the use of AC regimens for FET in ovulatory women with rASRM stage III-IV endometriosis or DE. We also recommend single ET at the blastocyst stage in this high-risk population.

REGISTRATION NUMBER

CRD42023401428.

Obstetric outcomes in women with pelvic endometriosis: a prospective cohort study

OBJECTIVE

To determine whether obstetric outcomes differ between women with endometriosis and those without, where all women undergo first-trimester screening for endometriosis.

DESIGN

A prospective observational cohort study.

SETTING

The Early Pregnancy Unit at University College London Hospital, United Kingdom.

PATIENTS

Women with a live pregnancy progressing beyond 12 weeks' gestation and concurrent endometriosis (n = 110) or no endometriosis (n = 393).

INTERVENTION

All women underwent a pelvic ultrasound examination in early pregnancy to examine for the presence of endometriosis and uterine abnormalities.

MAIN OUTCOME MEASURES

The primary outcome of interest was preterm birth, defined as delivery before 37 completed weeks' gestation. Secondary outcomes included late miscarriage, antepartum hemorrhage, placental site disorders, gestational diabetes, hypertensive disorders of pregnancy, neonates small for gestational age, mode of delivery, intrapartum sepsis, postpartum hemorrhage, and admission to the neonatal unit.

RESULTS

Women with a diagnosis of endometriosis did not have statistically significantly higher odds of preterm delivery (adjusted odds ratio [aOR] 1.85 [95% confidence interval {CI} 0.50-6.90]), but they did have higher odds of postpartum hemorrhage during cesarean section (aOR 3.64 [95% CI 2.07-6.35]) and admission of their newborn infant to the neonatal unit (aOR 3.24 [95% CI 1.08-9.73]). Women with persistent or recurrent deep endometriosis after surgery also had higher odds of placental site disorders (aOR 8.65 [95% CI 1.17-63.71]) and intrapartum sepsis (aOR 3.47 [95% CI 1.02-11.75]).

CONCLUSION

We observed that women with endometriosis do not have higher odds of preterm delivery, irrespective of their disease subtype. However, they do have higher odds of postpartum hemorrhage during the cesarean section and newborn admission to the neonatal unit.

Cervical angle as a possible predictor of abnormal placental position in women with endometriosis

BACKGROUND

We aimed to examine the effects of endometriosis on the rate of abnormal placentation by comparing the data of pregnant women with and without endometriosis.

METHODS

A case-control study was conducted to compare the perinatal outcomes between women with and without endometriosis. In the subgroup analysis, magnetic resonance imaging (MRI) scans of pregnant women with placenta previa were used to measure the cervical angle and its relationship with endometriosis. The cervical angle was measured as the angle between the cervical glands and the line perpendicular to the spinal column in each sagittal MRI section.

RESULTS

We retrospectively analyzed data from 3453 cases of singleton deliveries between 2015 and 2019 at two study facilities. Among them, 159 had clinically or surgically confirmed endometriosis. The odds ratio (OR) for abnormal placental position was significantly higher in pregnant women with endometriosis (OR. 2.82; 95% confidence interval [CI], 1.58-5.04). The OR was 3.21 (95% CI, 1.57-6.55) in the endometriosis-surgery group (91 patients) and 2.32 (95% CI, 0.91-5.88) in the non-surgery group (68 patients). Furthermore, 44 women who underwent pelvic MRI after 30 weeks of gestation were included to examine the cervical angle. Then, we compared the date of pregnant women with (n = 6) and without endometriosis (n = 38). Regardless of placental attachment position, the cervical angle was significantly lower in the group with than in the group without a history of endometriosis.

CONCLUSION

Pregnant women with a history of endometriosis may have stronger uterine retroversion, which could potentially contribute to abnormal placental positioning.

Increased risk of placenta previa and preterm birth in pregnant women with endometriosis/adenomyosis: A propensity-score matching analysis of a nationwide perinatal database in Japan

AIM

We aimed to investigate the associations of endometriosis and adenomyosis with pregnancy complications by using a large-scale Japanese database.

METHODS

We retrospectively analyzed 145 590 singleton pregnancies from the Japan Perinatal Registry Network Database. Pregnant women registered as having endometriosis or adenomyosis were designated as the case group (EA), whereas the control group (non-EA) was selected using propensity-score matching adjusted for variables such as age, parity, BMI, smoking history, and the use of assisted reproductive technology. The main outcomes included placental malposition, preterm birth, and hypertensive disorders of pregnancy (HDP).

RESULTS

In total, 1203 patients from both the EA and non-EA groups were matched and evaluated. The EA group showed significantly higher rates of placenta previa (odds ratio [OR], 3.01; 95% confidence interval [CI], 1.84-4.92), low-lying placenta (OR, 2.02; 95% CI, 1.06-3.86), and preterm birth (OR, 1.44; 95% CI, 1.13-1.84) than the non-EA group. However, no significant difference was observed in the incidence of HDP (OR, 1.22; 95% CI, 0.90-1.66).

CONCLUSION

The use of propensity-score matching to analyze a nationwide perinatal database in Japan clarified that EA was associated with increased pregnancy complications, specifically placental malposition, including placenta previa and low-lying placenta, and preterm birth, but not with HDP.

Adverse pregnancy outcomes associated with endometriosis in Ukraine: results a multicenter study

OBJECTIVE

Aim: To estimate pregnancy outcomes associated with endometriosis in Ukraine.

PATIENTS AND METHODS

Materials and Methods: We performed the multicentre prospective cohort study during the period from January 1st, 2019 to December 31st, 2021. The study included pregnant women aged ≥18 years hospitalized in 17 hospitals from 15 regions of Ukraine. Logistic regression analysis provided odds ratios (OR) with 95% confidence intervals (CI).

RESULTS

Results: Of the 27,558 women, 990 (3,6%) reported a diagnosis of endometriosis before pregnancy. In 990 deliveries, women with endometriosis had a higher risk of hypertension in pregnancy (OR 1.2, 95% CI 1.0-1.3), preeclampsia (OR 1.4, 95% CI 1.3-1.5), severe preeclampsia (OR 1.7, 95% CI 1.5-2.3), hemorrhage in pregnancy (OR 2.3, 95% CI 2.0-2.5), placental abruption (OR 2.0, 95% CI 1.7-2.3), placenta previa (OR 3.9, 95% CI 3.5-4.3), premature rupture of membranes (OR 1.7, 95% CI 1.5-1.8), and retained placenta (OR 3.1, 95% CI 1.4-6.6). The neonates had increased risks of preterm birth before 28 weeks (OR 3.1, 95% CI 2.7-3.6), birth before 34 weeks (OR 3.2, 95% CI 2.8-3.6), being small for gestational age (OR 1.5, 95% CI 1.4-1.6), being diagnosed with congenital malformations (OR 1.3, 95% CI 1.3-1.4), and neonatal death (OR 1.8, 95% CI 1.4-2.1).

CONCLUSION

Conclusions: Pregnant women with endometriosis are at elevated risk for serious and important adverse maternal, fetal and neonatal outcomes. The magnitude of these complications calls for more intensive antenatal care of pregnant women with endometriosis.

Establishment of the early prediction models of low-birth-weight reveals influential genetic and environmental factors: a prospective cohort study

BACKGROUND

Low birth weight (LBW) is a leading cause of neonatal morbidity and mortality, and increases various disease risks across life stages. Prediction models of LBW have been developed before, but have limitations including small sample sizes, absence of genetic factors and no stratification of neonate into preterm and term birth groups. In this study, we challenged the development of early prediction models of LBW based on environmental and genetic factors in preterm and term birth groups, and clarified influential variables for LBW prediction.

METHODS

We selected 22,711 neonates, their 21,581 mothers and 8,593 fathers from the Tohoku Medical Megabank Project Birth and Three-Generation cohort study. To establish early prediction models of LBW for preterm birth and term birth groups, we trained AI-based models using genetic and environmental factors of lifestyles. We then clarified influential environmental and genetic factors for predicting LBW in the term and preterm groups.

RESULTS

We identified 2,327 (10.22%) LBW neonates consisting of 1,077 preterm births and 1,248 term births. Our early prediction models archived the area under curve 0.96 and 0.95 for term LBW and preterm LBW models, respectively. We revealed that environmental factors regarding eating habits and genetic features related to fetal growth were influential for predicting LBW in the term LBW model. On the other hand, we identified that genomic features related to toll-like receptor regulations and infection reactions are influential genetic factors for prediction in the preterm LBW model.

CONCLUSIONS

We developed precise early prediction models of LBW based on lifestyle factors in the term birth group and genetic factors in the preterm birth group. Because of its accuracy and generalisability, our prediction model could contribute to risk assessment of LBW in the early stage of pregnancy and control LBW risk in the term birth group. Our prediction model could also contribute to precise prediction of LBW based on genetic factors in the preterm birth group. We then identified parental genetic and maternal environmental factors during pregnancy influencing LBW prediction, which are major targets for understanding the LBW to address serious burdens on newborns' health throughout life.

Endometriosis and Adverse Pregnancy Outcomes: A Nationwide Population-Based Study

Endometriosis is a major cause of infertility, and considering its pathophysiology, it is expected to affect pregnancy outcomes as well. This study aimed to evaluate whether endometriosis is associated with adverse pregnancy outcomes after successful conception. Data from singleton pregnancy deliveries between January 2014 and October 2019 were obtained from the Korean Health Insurance Review and Assessment Service database. We compared the clinical characteristics and adverse pregnancy outcomes of women with and without endometriosis. A total of 1,251,597 pregnant women were enrolled; of these, 32,951 (2.6%) were assigned to the endometriosis group. Women with endometriosis had significantly more adverse pregnancy outcomes than those without endometriosis. Adverse pregnancy outcomes associated with endometriosis included preterm labor, preterm birth, preeclampsia, fetal growth restriction, placenta previa, placental abruption, antepartum and postpartum hemorrhage, and stillbirth. This study also showed an increased risk of postpartum hemorrhage, blood transfusion, uterine artery embolization, and cesarean hysterectomy in the endometriosis group compared to the non- endometriosis group. The cesarean delivery rate was significantly higher in the endometriosis group than in the non-endometriosis group, even after excluding cases of antenatal obstetric complications that could increase the risk of cesarean delivery. Women with endometriosis not only have difficulty conceiving, but also have a significantly higher risk of adverse pregnancy outcomes.

Adverse Pregnancy Outcomes Associated with Endometriosis and Its Influencing Factors

Aim

To investigate the adverse pregnancy outcomes associated with endometriosis and its influencing factors.

Methods

A total of 188 endometriosis patients who gave birth at our hospital between June 2018 and January 2021 were screened for eligibility and included in the research group, while a control group of 188 nonendometriosis women who delivered at our hospital during the same period were also included as healthy controls. Pregnancy outcomes were the key outcome measure, and the relationship between endometriosis and unfavorable pregnancy outcomes, as well as the influencing factors, were explored.

Results

There was no significant difference in the risk of adverse pregnancy events such as miscarriage, ectopic pregnancy, termination of pregnancy, and fetal death between the two groups (P > 0.05). The differences in hypertensive disorder in pregnancy, gestational diabetes, placental abruption, fetal growth restriction, and luteal support between the two groups also failed to reach the statistical standard (P > 0.05). The two groups significantly differed in terms of cesarean delivery, preterm delivery, and placenta previa (1.92 (95% CI 1.33-2.85), 2.43 (95% CI 1.05-5.58), and 4.51 (95% CI 1.23-16.50)) (P < 0.05).

Conclusion

Endometriosis is an influential factor in adverse pregnancy outcomes and results in a high risk of preterm delivery, placenta previa, and cesarean delivery in patients. Mutual interactions exist among adverse pregnancy outcomes and thus require appropriate management.

Low STING expression promotes endometrial stromal cell invasion and migration via the STING/IRF-3/IFN-β1 pathway in eutopic endometrium of women with endometriosis

Aims: The primary aim of the current study was to elucidate the function of the stimulator of interferon genes (STING) in the eutopic endometrium of women with endometriosis. Materials and Methods: STING expression and signaling pathways were verified by western blot analysis and immunohistochemistry after si-STING treatment. Cell proliferation and invasion and migration were assessed using 5-ethynyl-2'-deoxyuridine and transwell assays, respectively. Results: Within endometriosis tissues, STING was primarily expressed in the stroma of the eutopic endometrium and glandular epithelium of the ectopic endometrium. However, STING expression was significantly lower in the eutopic endometrium of patients with endometriosis compared to controls (p < 0.05). Additionally, cell proliferation (0.2866 ± 0.01470 vs. 0.6911 ± 0.01796, ^****p < 0.0001), invasion (130.0 ± 6.296 vs. 424.1 ± 22.31, ^****p < 0.0001), and migration (82.93 ± 6.940 vs. 82.93 ± 6.940, ^****p < 0.0001) were significantly increased in the si-STING groups. Moreover, following si-STING transfection, the expression of phosphorylated IRF-3 and TBK1 that are involved in STING/IRF3/IFNb1 signaling pathway decreased. The addition of exogenous IFN-β1 effectively increased stromal cell invasion (IFN-β1-NC vs. IFN-β1-si-STING 274.7 ± 7.767 vs. 135.7 ± 12.63, ***p < 0.0001) and migration (IFN-β1-NC and IFN-β1-si-STING 28.53 ± 3.625 vs. 28.53 ± 3.625, ***p < 0.0001) without significantly impacting cell proliferation (si-STING vs. IFN-1β-si-STING 0.6874 ± 0.02081 vs. 0.7187 ± 0.02638, p = 0.795). Conclusions: The STING signaling pathway plays an important role in endometrial stromal cell proliferation, invasion and migration associated with endometriosis.

Pregnancy outcomes in women with endometriosis and/or ART use: a population-based cohort study

STUDY QUESTION

What is the association between endometriosis and adverse pregnancy outcomes with ART use and non-use?

SUMMARY ANSWER

Endometriosis and ART use are both associated with increased risk of preterm birth, antepartum haemorrhage, placenta praevia and planned birth (caesarean delivery or induction of labour).

WHAT IS KNOWN ALREADY

There are contradictory findings on the association between endometriosis and adverse pregnancy outcomes, and many large studies have not considered the effect of ART use.

STUDY DESIGN, SIZE, DURATION

Population-based cohort study of 578 221 eligible pregnancies during 2006-2015, comparing pregnancy outcomes across four groups (No endo/no ART, No endo/ART, Endo/no ART and Endo/ART).

PARTICIPANTS/MATERIALS, SETTING, METHODS

All female residents of New South Wales, Australia aged 15-45 years and their index singleton pregnancy of at least 20 weeks gestation or 400 g birthweight. Linked hospital, pregnancy/birth and mortality data were used. Modified Poisson regression with robust error variances was used to estimate adjusted risk ratios (aRRs) and 99% CIs, adjusting for sociodemographic and pregnancy factors.

MAIN RESULTS AND THE ROLE OF CHANCE

Compared to women without endometriosis who had pregnancies without ART use, there was increased risk of preterm birth (<37 weeks) in all groups [No endo/ART (aRR 1.85, 99% CI 1.46-2.34), Endo/no ART (aRR 1.24, 99% CI 1.06-1.44), Endo/ART (aRR 1.93, 99% CI 1.11-3.35)] and antepartum haemorrhage [No endo/ART (aRR 1.99, 99% CI 1.39-2.85), Endo/no ART (aRR 1.31, 99% CI 1.03-1.67), Endo/ART (aRR 2.69, 99% CI 1.30-5.56)] among pregnancies affected by endometriosis or ART use, separately and together. There was increased risk of placenta praevia [No endo/ART (aRR 2.26, 99% CI 1.42-3.60), Endo/no ART (aRR 1.66, 99% CI 1.18-2.33)] and planned birth [No endo/ART (aRR 1.08, 99% CI 1.03-1.14), Endo/no ART (aRR 1.11, 99% CI 1.07-1.14)] among pregnancies with endometriosis or ART use, separately. There was increased risk of placental abruption [No endo/ART (aRR 2.36, 99% CI 1.12-4.98)], maternal morbidity [No endo/ART (aRR 1.67, 99% CI 1.07-2.62)] and low birthweight (<2500 g) [No endo/ART (aRR 1.45, 99% CI 1.09-1.93)] among pregnancies with ART use without endometriosis. There was decreased risk of having a large-for-gestational age infant [Endo/no ART (aRR 0.83, 99% CI 0.73-0.94)] among pregnancies with endometriosis without ART use.

LIMITATIONS, REASONS FOR CAUTION

Endometriosis is often under-diagnosed and women with a history of hospital diagnosis of endometriosis may represent those with more symptomatic or severe disease. If the effects of endometriosis on pregnancy are greater for those with more severe disease, our results may over-estimate the effect of endometriosis on adverse pregnancy outcomes at a population level. We were unable to assess the effect of endometriosis stage or typology on the study outcomes.

WIDER IMPLICATIONS OF THE FINDINGS

These results suggest that women with endometriosis including those who used ART to achieve pregnancy are a higher-risk obstetric group requiring appropriate surveillance and management during their pregnancy.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by the Prevention Research Support Program, funded by the New South Wales Ministry of Health. The funder had no role in the design, data collection and analysis, interpretation of results, manuscript preparation or the decision to submit the manuscript for publication. The authors have no conflicts of interest.

TRIAL REGISTRATION NUMBER

N/A.

Endometriosis does not seem to be an influencing factor of hypertensive disorders of pregnancy in IVF / ICSI cycles

INTRODUCTION

To evaluate whether the incidence of hypertensive disorders of pregnancy (HDP) in pregnant women was related to endometriosis (EM), ovulation and embryo vitrification technology.

METHODS

A retrospective cohort study was conducted on the clinical data of 3674 women who were treated with IVF / ICSI in the Reproductive Medicine Center of the First Affiliated Hospital of Sun Yat-sen University and maintained clinical pregnancy for more than 20 weeks. All pregnancies were followed up until the end of pregnancy. The follow-up consisted of recording the course of pregnancy, pregnancy complications, and basic situation of newborns.

RESULTS

Compared with NC-FET without EM, HRT-FET without EM was found to have a higher incidence of HDP during pregnancy (2.7% V.S. 6.1%, P<0.001); however, no significant difference was found in the incidence of HDP between NC-FET and HRT-FET combined with EM (4.0% V.S. 5.7%, P>0.05). In total frozen-thawed embryo transfer (total-FET), the incidence of HDP in the HRT cycle without ovulation (HRT-FET) was observed to be higher than that in the NC cycle with ovulation (NC-FET) (2.8% V.S. 6.1%, P<0.001). In patients with EM, no significant difference was found in the incidence of HDP between fresh ET and NC-FET (1.2% V.S. 4.0%, P>0.05).

CONCLUSION

EM does not seem to have an effect on the occurrence of HDP in assisted reproductive technology. During the FET cycle, the formation of the corpus luteum may play a protective role in the occurrence and development of HDP. Potential damage to the embryo caused by cryopreservation seems to have no effect on the occurrence of HDP.

Association between Endometriosis and Delivery Outcomes: A Systematic Review and Meta-Analysis

Endometriosis is a common benign gynecological disorder; however, delivery outcomes concerning pregnancies with endometriosis remain understudied. This study aimed to assess the effect of endometriosis on delivery outcomes, including the rate of instrumental delivery, cesarean delivery (CD), postpartum hemorrhage (PPH), and perioperative complications during CD. A systematic literature review was conducted using multiple computerized databases, and 28 studies met the inclusion criteria. Pooled analysis showed that histologically diagnosed endometriosis was associated with an increased rate of instrumental delivery (odds ratio [OR] 1.26, 95% confidence interval [CI] 1.02-1.56) and an increased risk of CD (adjusted OR 2.59, 95%CI 1.32-5.07). In our analysis, histologically diagnosed endometriosis was not associated with an increased rate of PPH; however, one retrospective study reported that endometriosis increased the rate of PPH during CD (adjusted OR 1.7, 95%CI 1.5-2.0). Two studies examined perioperative complications during CD, and women with deep endometriosis had a higher rate of bowel resection or bladder injury than those without endometriosis. Our findings suggest that endometriosis is a significant risk factor for instrumental delivery and CD and may be associated with a higher rate of PPH and intraoperative complications during CD.

Placenta Accreta Spectrum Disorder Complicated with Endometriosis: Systematic Review and Meta-Analysis

This study aimed to assess the relationship between placenta accreta spectrum disorder (PASD) and endometriosis. The relationships among pregnancy, assisted reproductive technology (ART), placenta previa, ART-conceived pregnancy and PASD were also determined. A systematic literature review was conducted using multiple computerized databases. Forty-eight studies (1990–2021) met the inclusion criteria. According to the adjusted pooled analysis (n = 3), endometriosis was associated with an increased prevalence of PASD (adjusted odds ratio [OR] 3.39, 95% confidence interval [CI] 1.96–5.87). In the included studies, the ART rate ranged from 18.2% to 37.2% for women with endometriosis. According to the adjusted pooled analysis, women who used ART were more likely to have placenta previa (n = 13: adjusted OR 2.96, 95%CI, 2.43–3.60) and PASD (n = 4: adjusted OR 3.54, 95%CI 1.86–6.76) than those who did not use ART. According to the sensitivity analysis using an unadjusted analysis accounting for the type of ART, frozen embryo transfer (ET) was associated with an increased risk of PASD (n = 4: OR 2.79, 95%CI, 1.22−6.37) compared to fresh ET. Endometriosis may be associated with an increased rate of PASD. Women with placenta previa complicated with endometriosis who conceived using frozen ET may be a high risk for PASD.

Placenta Previa Complicated with Endometriosis: Contemporary Clinical Management, Molecular Mechanisms, and Future Research Opportunities

Endometriosis is a common gynecological disease characterized by chronic inflammation, with an estimated prevalence of approximately 5–15% in reproductive-aged women. This study aimed to assess the relationship between placenta previa (PP) and endometriosis. We performed a systematic review of the literature until 30 June 2021, and 24 studies met the inclusion criteria. Using an adjusted pooled analysis, we found that women with endometriosis had a significantly increased rate of PP (adjusted odds ratio (OR) 3.17, 95% confidence interval (CI) 2.58–3.89) compared to those without endometriosis. In an unadjusted analysis, severe endometriosis was associated with an increased prevalence of PP (OR 11.86, 95% CI 4.32–32.57), whereas non-severe endometriosis was not (OR 2.16, 95% CI 0.95–4.89). Notably, one study showed that PP with endometriosis was associated with increased intraoperative bleeding (1.515 mL versus 870 mL, p < 0.01) compared to those without endometriosis. Unfortunately, no studies assessed the molecular mechanisms underlying PP in patients with endometriosis. Our findings suggest that there is a strong association between endometriosis and a higher incidence of PP, as well as poor surgical outcomes during cesarean delivery. Therefore, the development of novel therapeutic agents or methods is warranted to prevent PP in women with endometriosis.

The association of endometriosis with placenta previa and postpartum hemorrhage: a systematic review and meta-analysis

OBJECTIVE

This study aimed to review the effect of endometriosis on the prevalence of placenta previa and postpartum hemorrhage in pregnant patients and the surgical outcomes of pregnant patients with endometriosis developing placenta previa.

DATA SOURCES

In compliance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, a systematic review of the literature was conducted on December 31, 2020, using PubMed, Scopus, and the Cochrane Library.

STUDY ELIGIBILITY CRITERIA

Comparative studies between pregnant women with and without endometriosis and studies that investigated the surgical outcomes of patients with and without endometriosis developing placenta previa were included.

METHODS

Here, 2 reviewers independently screened the titles and abstracts, completed data extraction, and assessed the reporting quality using the Risk of Bias in Nonrandomized Studies of Interventions tool.

RESULTS

Overall, 19 studies (from 2010 to 2020) met the inclusion criteria (98,463 pregnancies with endometriosis and 7,184,313 pregnancies without endometriosis). In the adjusted pooled analysis, endometriosis was associated with a higher rate of placenta previa (adjusted odds ratio, 3.17; 95% confidence interval, 2.58-3.89), whereas the incidence of postpartum hemorrhage was similar between pregnant women with and without endometriosis (adjusted odds ratio, 1.15; 95% confidence interval, 0.99-1.34). When the analysis was restricted to histologically confirmed endometriosis cases, the relationship of endometriosis with placenta previa (adjusted odds ratio, 4.23; 95% confidence interval, 1.74-10.30) and postpartum hemorrhage (adjusted odds ratio, 1.29; 95% confidence interval, 0.50-3.34) was consistent with results from the nonrestricted analysis. There was no study that examined the surgical outcomes of patients with endometriosis developing placenta previa patients. However, there are 3 studies that examined the effect of endometriosis on surgical outcomes during cesarean delivery: 1 study showing that endometriosis was associated with increased intraoperative bleeding during emergent cesarean delivery; the other study showing that endometriosis was associated with an increased incidence of postpartum hemorrhage during cesarean delivery (adjusted odds ratio, 1.1; 95% confidence interval, 1.0-1.2), especially in primiparous women with singleton pregnancies (adjusted odds ratio, 1.7; 95% confidence interval, 1.5-2.0); and another study suggesting a significantly higher rate of hysterectomy (7.1%) and bladder injury (7.1%) in patients with endometriosis than in those without endometriosis.

CONCLUSION

Endometriosis can potentially be associated with adverse surgical outcomes during cesarean delivery. Although there is a correlation between endometriosis and increased rate of placenta previa, the surgical outcomes of patients with endometriosis developing placenta previa remain understudied.

Endometriosis and Risk of Adverse Pregnancy Outcome: A Systematic Review and Meta-Analysis

Background: This systematic review and meta-analysis summarizes the evidence for the association between endometriosis and adverse pregnancy outcome, including gestational hypertension, pre-eclampsia, low birth weight, and small for gestational age, preterm birth, placenta previa, placental abruption, cesarean section, stillbirth, postpartum hemorrhage, spontaneous hemoperitoneum in pregnancy, and spontaneous bowel perforation in pregnancy. Methods: We performed the literature review in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA), by searches in PubMed and EMBASE, until 1 November 2020 (PROSPERO ID CRD42020213999). We included peer-reviewed observational cohort studies and case-control studies and scored them according to the Newcastle–Ottawa Scale, to assess the risk of bias and confounding. Results: 39 studies were included. Women with endometriosis had an increased risk of gestational hypertension, pre-eclampsia, preterm birth, placenta previa, placental abruption, cesarean section, and stillbirth, compared to women without endometriosis. These results remained unchanged in sub-analyses, including studies on spontaneous pregnancies only. Spontaneous hemoperitoneum in pregnancy and bowel perforation seemed to be associated with endometriosis; however, the studies were few and did not meet the inclusion criteria. Conclusions: The literature shows that endometriosis is associated with an increased risk of gestational hypertension, pre-eclampsia, preterm birth, placenta previa, placental abruption, cesarean section, and stillbirth.