Uterine fibroids and preterm birth risk: A systematic review and meta-analysis

Uterine Leiomyomas and Reproduction

There is a prevailing opinion by gynecologists, much of it based on expert opinion or anecdotal evidence, that myomas are detrimental to pregnancy. Newer data challenge much of this dogma, but incorrect assumptions remain. Although not impeccable, multiple data address the correlation between myomas and reproduction, and some emerging evidence addresses surgical removal of these myomas and subsequent outcomes. A thorough literature search was performed, and the amassed data were analyzed to answer some of our most important queries about the role that myomas play in pregnancy and delivery. Uterine leiomyomas ultimately decrease in size during late pregnancy and postpartum. Spontaneous abortion rates are similar in women with and without leiomyomas. The data addressing leiomyoma effects on preterm prelabor rupture of membranes, placental abruption, cesarean delivery, and postpartum hemorrhage rates are conflicting, but the best evidence does not show a significant correlation compared with women without myomas. Preterm delivery rates are elevated in women with leiomyomas. Myomectomy does not decrease preterm deliveries and may increase this risk. Women with myomectomies have increased elective cesarean delivery rates and more blood loss at delivery compared with women with leiomyomas in situ.

Role of inflammation and immune response in the pathogenesis of uterine fibroids: Including their negative impact on reproductive outcomes

Uterine fibroids (UFs), the most common tumors in women of reproductive age, are characterized by sex steroid-dependent growth and excessive deposition of extracellular matrix (ECM) surrounding UF smooth muscle cells. Women with symptomatic UFs experience heavy menstrual bleeding and consequent iron-deficiency anemia. They also have a risk of recurrent pregnancy loss, preterm birth, and cesarean delivery, indicating that UFs can negatively affect reproductive outcomes. Various types of immune cells, including innate and adaptive cells, are observed in UFs; however, the impact of these cells on the pathophysiology of UFs remains unclear. Inflammation may play important roles in the growth of UFs, and expression levels of proinflammatory and inflammatory cytokines, such as interleukin (IL)-1, IL-6, IL-10, TNF-α, and TGF-β, are upregulated in UFs. These cytokines play important roles in the interaction between growth factors and ECM that is regulated by the sex steroids estrogen and progesterone. Furthermore, proinflammatory mediators are upregulated in females with UFs, with higher expression levels in the endometrium with submucosal and intramural UFs than in the endometrium without UFs, indicating that these proinflammatory cytokines may impair endometrial receptivity, leading to implantation failure in in vitro fertilization programs. Hormonal treatments using gonadotropin releasing hormone analogs and the selective progesterone receptor modulator ulipristal acetate significantly shrink UFs and improve UF-related symptoms. These compounds can regulate local inflammation in UFs and adjacent myometrium. Controlling and improving local inflammation caused by UFs may represent a novel therapeutic strategy for UFs and potentially improve reproductive outcomes in women with symptomatic UFs.

Pregnancy and delivery outcomes after abdominal vs. laparoscopic myomectomy: an evaluation of an American population database

OBJECTIVE

To evaluate population characteristics and obstetric complications after abdominal myomectomy vs. laparoscopic myomectomy.

DESIGN

Retrospective cohort study.

SETTING

Healthcare Cost and Utilization Project Nationwide Inpatient Sample (HCUP-NIS) data representative of over 20% of all hospital admissions in the United States.

PATIENT(S)

A total of 13,868 and 338 pregnancies after abdominal or laparoscopic myomectomy, respectively.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Obstetric outcomes after abdominal or laparoscopic myomectomies were collected using hospital discharges from 2004 to 2014 inclusively, and adjusted using multiple and binomial logistic regression in different models for age, obesity, chronic hypertension, and pregestational diabetes mellitus. Pregnancy, delivery, and neonatal outcomes were analyzed.

RESULT(S)

Abdominal myomectomy were characterized by younger patients, lower rates of White chronic hypertension, pregestational diabetes, active smoking, illicit drug use, and higher rates of previous cesarean delivery, and multiple gestations when compared with laparoscopic myomectomy. Pregnant women with laparoscopic myomectomy had decreased rates of pregnancy-induced hypertension (adjusted risk ratios [aRR], 0.12; 95% confidence intervals [CI], 0.006-0.24]), gestational hypertension (aRR, 0.24; 95% CI, 0.08-0.76), pre-eclampsia (aRR, 0.18; 95% CI, 0.07-0.48), and pre-eclampsia or eclampsia superimposed on chronic hypertension (aRR, 0.03; 95% CI, 0.005-0.3), gestational diabetes mellitus (aRR, 0.14; 95% CI, 0.06-0.34), preterm premature rupture of membranes (aRR, 0.14; 95% CI, 0.02-0.96), preterm delivery (aRR, 0.36; 95% CI, 0.23-0.55), and cesarean delivery (aRR, 0.01; 95% CI, 0.007-0.01) and small for gestational age (aRR, 0.15; 95% CI, 0.005-0.04), compared with abdominal myomectomy group. Laparoscopic myomectomy group had a higher rate of spontaneous (aRR, 35.57; 95% CI, 22.53-62.66), and operative vaginal delivery (aRR, 10.2; 95% CI, 8.3-12.56), uterine rupture (aRR, 6.1; 95% CI, 3.2-11.63), postpartum hemorrhage (aRR, 3.54; 95% CI, 2.62-4.8), hysterectomy (aRR, 7.74; 95% CI, 5.27-11.4), transfusion (aRR, 3.34; 95% CI, 2.54-4.4), pulmonary embolism (aRR, 7.44; 95% CI, 2.44-22.71), disseminated intravascular coagulation (aRR, 2.77; 95% CI, 1.47-5.21), maternal infection (aRR, 1.66; 95% CI, 1.1-2.5), death (aRR, 2.04; 95% CI, 1.31-3.2), and intrauterine fetal death (aRR, 2.99; 95% CI, 1.72-5.2) compared with the abdominal myomectomy group.

CONCLUSION(S)

Women who had a previous abdominal myomectomy have underlying risk factors for hypertension disorders of pregnancy and gestational diabetes. Women who underwent laparoscopic myomectomies have higher risks of bleeding, uterine rupture, resultant complications, and death, and should be monitored as high-risk patients, like abdominal myomectomies.

The association between uterine fibroid number and size and risk of preterm birth

BACKGROUND

While the association between uterine fibroids and preterm birth is well known, data regarding whether fibroid characteristics such as number and size modify such risk are limited.

OBJECTIVE

To evaluate the association between fibroid number and size and risk of preterm birth and determine whether these characteristics impact the severity of preterm birth.

STUDY DESIGN

Multicenter retrospective cross-sectional study including all patients with singleton gestations who had at least one prenatal ultrasound at 18 0/7 weeks of gestation or later and delivered within a large university health system from January 1, 2019 to December 31, 2022. When fibroids were identified on ultrasound, their characteristics (i.e., number, size, and location) were documented. Patients with more than one delivery during the study period had only their first included for analysis. The primary outcome of preterm birth, stratified by gestational age (<37, <34, <32, and <28 weeks), was assessed based on fibroid number (1, 2, ≥3) and size (largest dimension <5 cm, 5-10 cm, >10 cm) separately in patients who had prenatally detected fibroids compared to those with no fibroids. Multivariate logistic regression was performed to adjust for potential confounders. Data were presented as adjusted odds ratios (aOR) with 95% confidence intervals (CI).

RESULTS

Among the 65,950 patients studied, 4,421 (6.7%) had at least one fibroid. The prevalence of preterm birth <37 weeks was 8.6%. The presence of any fibroid, regardless of number, was associated with an increased risk of preterm birth <37 weeks compared to no fibroids (1 fibroid: 12.8% vs. 8.2%, aOR 1.26, 95% CI 1.10-1.44; 2 fibroids: 12.7% vs. 8.2%, aOR 1.27, 95% CI 1.01-1.58; ≥3 fibroids: 18.5% vs. 8.2%, aOR 1.60, 95% CI 1.29-1.99). Patients with 2 fibroids were at increased risk of preterm birth <34, <32, and <28 weeks compared to those without fibroids, while patients with ≥3 fibroids were at increased risk of preterm birth <34 and <28 weeks compared to those without fibroids. The presence of at least one fibroid, regardless of the size of their largest dimension, was associated with an increased risk of preterm birth <37 weeks compared to no fibroids (<5 cm: 12.4% vs. 8.2%, aOR 1.19, 95% CI 1.04-1.36; 5-10 cm: 15.5% vs. 8.2%, aOR 1.47, 95% CI 1.23-1.75; >10 cm: 21.4% vs. 8.2%, aOR 2.26, 95% CI 1.55-3.28). Increasing fibroid size by largest dimension was associated with an increased risk of preterm birth <34 weeks. Patients with fibroids >10 cm by largest dimension were at increased risk of preterm birth <28 weeks compared to those without fibroids. There was no association between increasing fibroid size by largest dimension and preterm birth <32 weeks.

CONCLUSIONS

Data from this large cohort suggest that fibroid characteristics such as number and size are associated with preterm birth and impact the severity of preterm birth. Increasing fibroid number and size is associated with a higher risk of earlier preterm birth compared to those without fibroids.

Mapping evidence on the distribution of uterine fibroids in sub-Saharan Africa: A scoping review protocol

BACKGROUND

Uterine fibroids are the most common pelvic benign tumours found in reproductive-aged women and may affect up to 70% of all women by menopause. Uterine fibroids place a heavy burden on women and society resulting in poor quality of life, impaired self-image, and impaired social, sexual, emotional, and physical well-being of affected individuals.

AIM

This study aims to map the evidence on the burden of uterine fibroids in Sub-Saharan Africa; uterine fibroids' burden by age, uterine fibroids' geographic burden, uterine fibroids' cost estimation and reported experiences among women diagnosed with uterine fibroids.

SETTING

Articles will be selected from countries within Sub-Saharan Africa.

METHODS AND ANALYSIS

This scoping review will be guided by the Arksey & O'Malley framework, enhanced by Levac et al (2010). The following electronic databases will be searched; PubMed, EBSCOhost (Cumulated Index to Nursing and Allied Health Literature and Health Source), Medical Literature Analysis and Retrieval System Online, Cochrane Library, Scopus, Web of Science, Africa Journal Online, and Google Scholar. The Population Concept and Context (PCC) framework will be used and the PRISMA flow diagram will also be used to show the literature search and selection of studies. Descriptive data analysis will be used; results will be presented in themes, narrative summaries, tables, and charts.

DISCUSSION

The study anticipates finding relevant literature on the distribution of uterine fibroids, the burden of uterine fibroids in terms of geographic distribution, age distribution, and cost approximation related to the disease. This will assist in identifying research gaps to guide future research contribute to the body of scientific knowledge and develop preventative strategies for the disease.

The influence of uterine fibroids on adverse outcomes in pregnant women: a meta-analysis

OBJECTIVE

The objective of the meta-analysis was to determine the influence of uterine fibroids on adverse outcomes, with specific emphasis on multiple or large (≥ 5 cm in diameter) fibroids.

MATERIALS AND METHODS

We searched PubMed, Embase, Web of Science, ClinicalTrials.gov, China National Knowledge Infrastructure (CNKI), and SinoMed databases for eligible studies that investigated the influence of uterine fibroids on adverse outcomes in pregnancy. The pooled risk ratio (RR) of the variables was estimated with fixed effect or random effect models.

RESULTS

Twenty-four studies with 237 509 participants were included. The pooled results showed that fibroids elevated the risk of adverse outcomes, including preterm birth, cesarean delivery, placenta previa, miscarriage, preterm premature rupture of membranes (PPROM), placental abruption, postpartum hemorrhage (PPH), fetal distress, malposition, intrauterine fetal death, low birth weight, breech presentation, and preeclampsia. However, after adjusting for the potential factors, negative effects were only seen for preterm birth, cesarean delivery, placenta previa, placental abruption, PPH, intrauterine fetal death, breech presentation, and preeclampsia. Subgroup analysis showed an association between larger fibroids and significantly elevated risks of breech presentation, PPH, and placenta previa in comparison with small fibroids. Multiple fibroids did not increase the risk of breech presentation, placental abruption, cesarean delivery, PPH, placenta previa, PPROM, preterm birth, and intrauterine growth restriction. Meta-regression analyses indicated that maternal age only affected the relationship between uterine fibroids and preterm birth, and BMI influenced the relationship between uterine fibroids and intrauterine fetal death. Other potential confounding factors had no impact on malposition, fetal distress, PPROM, miscarriage, placenta previa, placental abruption, and PPH.

CONCLUSION

The presence of uterine fibroids poses increased risks of adverse pregnancy and obstetric outcomes. Fibroid size influenced the risk of breech presentation, PPH, and placenta previa, while fibroid numbers had no impact on the risk of these outcomes.

Uterine Leiomyomata as a Cause of Abdominal Compartment Syndrome in the Postpartum Period

Uterine leiomyomas are common benign smooth muscle tumors that often occur during the reproductive years. Although many cases may not result in significant complications, negative pregnancy outcomes have been associated with the size and location of the fibroids. Degeneration of fibroids can occur as early as the late first trimester when they undergo significant volumetric growth, contributing to pain during pregnancy. While myomectomy is typically avoided during pregnancy, conservative management with anti-inflammatory medications may be effective. Surgical removal or preterm delivery may be necessary if symptoms persist. Abdominal compartment syndrome (ACS) is a rare condition characterized by sustained elevated intra-abdominal pressure leading to organ failure. Although ACS resulting from large-volume leiomyomas in the postpartum period has not been previously described, we present a case of a 25-year-old patient with massive uterine fibroids who required indicated preterm delivery via primary cesarean section at 25 weeks gestation. Her postpartum course was complicated by ACS, requiring emergent surgical decompression. When a large fibroid burden is present during pregnancy or in the postpartum period, ACS should be considered in the differential diagnosis. Early diagnosis and timely surgical decompression are necessary to prevent organ dysfunction and worsening maternal outcomes.

Associations of Pregnancy Per- and Polyfluoroalkyl Substance Concentrations and Uterine Fibroid Changes across Pregnancy: NICHD Fetal Growth Studies - Singletons Cohort

BACKGROUND

Fibroids (hormonally responsive benign tumors) often undergo volume changes in pregnancy. Because per- and polyfluoroalkyl substances (PFAS) disrupt hormonal signaling, they might affect fibroid growth. We assessed associations between PFAS and fibroid changes in pregnancy.

METHODS

We analyzed seven PFAS, including perfluorohexanesulfonic acid (PFHxS), perfluorooctanesulfonic acid (PFOS), perfluorodecanoic acid (PFDA), and perfluoroundecanoic acid (PFUnDA), in plasma collected at 10-13 wk gestation from 2,621 women in the NICHD Fetal Growth Studies - Singletons cohort (2009-2013). Sonographers recorded fibroid number and volume of the three largest fibroids during up to six timed ultrasounds. Generalized linear models assessed associations of baseline log 2 - transformed PFAS and fibroid number, volume, and presence, and weighted quantile sum regression evaluated the PFAS mixture. Generalized linear mixed models with random intercepts assessed associations of PFAS and longitudinal fibroid number and total volume. Volume analyses were stratified by total volume at first visualization [equivalent to a fibroid < 1 cm (small), 1  to < 3 cm (medium), or ≥ 3 cm (large) in diameter].

RESULTS

Fibroid prevalence was 9.4% (n = 245 women). PFAS were not associated with changes in fibroid number, but were associated with volume trajectory, depending on baseline volume. Among women with small volume, PFAS were associated with fibroid growth: Each doubling in PFHxS and PFOS concentrations was associated with 3.6% [95% confidence interval (CI): 0.2, 7.0 and 5.2% (95% CI: - 0.4 , 11.1)] greater weekly fibroid growth, respectively. Among women with medium volume, PFAS were associated with shrinking: Doublings in PFOS, PFDA, and PFUnDA concentrations were associated with 1.9% (95% CI: 0.4, 3.3), 1.2% (95% CI: 0.1, 2.4), and 1.6% (95% CI: 0.4, 2.8) greater weekly fibroid volume reduction, respectively.

DISCUSSION

Certain PFAS were associated with fibroid growth among women with small fibroids and decreases among women with medium fibroids. PFAS were not associated with fibroid prevalence or number; therefore, PFAS may influence prevalent fibroids rather than initiating fibroid development. https://doi.org/10.1289/EHP11606.

Reproductive and Obstetric Outcomes after UAE, HIFU, and TFA of Uterine Fibroids: Systematic Review and Meta-Analysis

Novel treatment options for uterine fibroids, such as uterine artery embolization (UAE), ultrasound-guided and magnetic resonance-guided high-intensity focused ultrasound (USgHIFU and MRgHIFU), and transcervical radiofrequency ablation (TFA) methods, are widely used in clinical practice. This systematic review and meta-analysis (CRD42022297312) aims to assess and compare reproductive and obstetric outcomes in women who underwent these minimally invasive approaches for uterine fibroids. The search was performed in PubMed, Google Scholar, ScienceDirect, Cochrane Library, Scopus, Web of Science and Embase. Risk of bias was assessed using the Newcastle-Ottawa Scale (NOS) and Cochrane guidelines. The articles were selected to meet the following eligibility criteria: (1) research article, (2) human subject research, and (3) the study of pregnancy outcomes after the treatment of uterine fibroids by either one of three methods-UAE, HIFU, and TFA. The analysis of 25 eligible original articles shows a similar rate of live births for UAE, USgHIFU, MRgHIFU, and TFA (70.8%, 73.5%, 70%, and 75%, respectively). The number of pregnancies varied considerably among these studies, as well as the mean age of pregnant women. However, the results of pregnancy outcomes for TFA are insufficient to draw firm conclusions, since only 24 women became pregnant in these studies, resulting in three live births. The miscarriage rate was highest in the UAE group (19.2%). USgHIFU was associated with a higher rate of placental abnormalities compared to UAE (2.8% vs. 1.6%). The pooled estimate of pregnancies was 17.31% to 44.52% after UAE, 18.69% to 78.53% after HIFU, and 2.09% to 7.63% after TFA. The available evidence confirmed that these minimally invasive uterine-sparing treatment options for uterine fibroids are a good approach for patients wishing to preserve their fertility, with comparable reproductive and obstetric outcomes among the different techniques.

Natural history of fibroids in pregnancy: National Institute of Child Health and Human Development Fetal Growth Studies - Singletons cohort

OBJECTIVE

To describe the natural history of fibroids in pregnancy in a racially diverse cohort and explore whether fibroid changes were associated with participant characteristics.

DESIGN

Prospective cohort study.

SETTING

Twelve clinical sites.

PATIENT(S)

Pregnant women (n = 2774; 27% non-Hispanic White, 28% non-Hispanic Black, 29% Hispanic, 17% Asian/Pacific Islander) who had up to 6 obstetric ultrasounds in gestational weeks 10-41.

INTERVENTION(S)

Sonographers recorded fibroid number and volume of the 3 largest fibroids at each visit. Generalized linear mixed models estimated the trajectories of fibroid number and total volume (overall and stratified by total volume at first visualization: equivalent to a fibroid of <1 cm [small], 1 to <3 cm [medium], or ≥3 cm [large] in diameter). We tested the interactions between the trajectories and race/ethnicity, age (<26, 26-30, 31-34, and ≥35 years), body mass index (<25, 25-29.9, and ≥30 kg/m2), previous miscarriage, parity, and fetal sex, adjusted for total volume at first visualization.

MAIN OUTCOME MEASURE(S)

Average change in total fibroid volume during pregnancy.

RESULT(S)

Overall, 9.6% (266/2,774) of women had a visualized fibroid at any time during pregnancy, including 9% (67/745) of non-Hispanic White women, 14% (106/770) of non-Hispanic Black women, 6% (47/794) of Hispanic women, and 10% (46/465) of Asian or Pacific Islander women. The mean total fibroid volume decreased by 1.0% (95% confidence interval [CI], -1.9%, -0.2%) per week, with a variation in starting total volume. On average, the total volume increased by 2.0% (95% CI, -0.3%, 4.5%) per week among women with small volume; decreased by 0.5% (95% CI, -2.0%, 1.0%) per week among women with medium volume; and decreased by 2.2% (95% CI, -3.4%, -1.0%) per week among women with large volume at first visualization. The volume change also varied by race or ethnicity, parity, age, and miscarriage history. For example, non-Hispanic Black women's total fibroid volume decreased more than those of non-Hispanic White, Hispanic and Asian/Pacific Islander women (-2.6%, 0.1%, 0.5%, and 0.9% average change per week, respectively). The visualized fibroid number declined on an average by 1.2% per week (95% CI, -1.9%, -0.5%) without significant variation by demographic characteristics.

CONCLUSION(S)

The total fibroid volume declined on average throughout pregnancy. However, summarizing across all fibroids disguises substantial heterogeneity by starting total fibroid volume and maternal characteristics. The findings may be a useful reference for clinicians to anticipate how fibroids may change in obstetric patients.

CLINICAL TRIAL REGISTRATION NUMBER

NCT00912132.

Importance of Fibrosis in the Pathogenesis of Uterine Leiomyoma and the Promising Anti-fibrotic Effects of Dipeptidyl Peptidase-4 and Fibroblast Activation Protein Inhibitors in the Treatment of Uterine Leiomyoma

Uterine fibroid or leiomyoma is the most common benign uterus tumor. The tumor is primarily composed of smooth muscle (fibroid) cells, myofibroblast, and a significant amount of extracellular matrix components. It mainly affects women of reproductive age. They are uncommon before menarche and usually disappear after menopause. The fibroids have excessive extracellular matrix components secreted by activated fibroblast cells (myofibroblast). Myofibroblast has the characteristics of fibroblast and smooth muscle cells. These cells possess contractile capability due to the expression of contractile proteins which are normally found only in muscle tissues. The rigid nature of the tumor is responsible for many side effects associated with uterine fibroids. The current drug treatment strategies are primarily hormone-driven and not anti-fibrotic. This paper emphasizes the fibrotic background of uterine fibroids and the mechanisms behind the deposition of excessive extracellular matrix components. The transforming growth factor-β, hippo, and focal adhesion kinase-mediated signaling pathways activate the fibroblast cells and deposit excessive extracellular matrix materials. We also exemplify how dipeptidyl peptidase-4 and fibroblast activation protein inhibitors could be beneficial in reducing the fibrotic process in leiomyoma. Dipeptidyl peptidase-4 and fibroblast activation protein inhibitors prevent the fibrotic process in organs such as the kidneys, lungs, liver, and heart. These inhibitors are proven to inhibit the signaling pathways mentioned above at various stages of their activation. Based on literature evidence, we constructed a narrative review on the mechanisms that support the beneficial effects of dipeptidyl peptidase-4 and fibroblast activation protein inhibitors for treating uterine fibroids.

Uterine Fibroids Causing Preterm Birth: A New Pathophysiological Hypothesis on the Role of Fibroid Necrosis and Inflammation

According to recent studies and observations in clinical practice, uterine fibroids increase the risk of preterm birth. There are several theories on the pathogenesis of preterm birth in the presence of fibroids. One theory proclaims that fibroid necrosis leads to preterm birth, though pathophysiological mechanisms have not been described. Necrotic tissue secretes specific cytokines and proteins and we suggest these to be comparable to the inflammatory response leading to spontaneous preterm birth. We hypothesize that fibroid necrosis could induce preterm parturition through a similar inflammatory response. This new hypothesis generates novel perspectives for future research and the development of preventative strategies for preterm birth. Moreover, we emphasize the importance of the recognition of fibroids and especially fibroid necrosis by clinicians during pregnancy.

The risk of preterm birth in women with uterine fibroids: A systematic review and meta-analysis

BACKGROUND

Fibroids have been identified as a possible risk factor for preterm birth, however, the magnitude of this risk is unclear. Our objective was to determine the risk of total, spontaneous, and medically indicated preterm birth in women with fibroids.

METHODS

A literature search was performed on 9 June 2021. We selected studies reporting on preterm birth in women with and without fibroids. Fibroids had to be diagnosed by routine ultrasound before or during pregnancy. Main outcomes were total preterm birth <37, <34, <32, and <28 weeks of gestation, and spontaneous and medically indicated preterm birth. Two authors independently performed study selection, data extraction and quality assessment. We performed quality assessment with the Newcastle-Ottawa scale. Meta-analyses were presented as Odds Ratios (ORs) with 95% Confidence Intervals (95%CIs).

MAIN RESULTS

The search yielded 2078 unique articles of which 11 were included. Meta-analysis for preterm birth <37 weeks of gestation included 256,650 singleton deliveries: 12,309 with fibroids and 244,341 without fibroids. Women with fibroids had a higher rate of preterm birth (11.6% versus 9.0%; OR 1.66, 95%CI 1.29-2.14). Fibroids were also associated with preterm birth <34 (OR 1.88, 95%CI 1.34-2.65), <32 (OR 2.03, 95%CI 1.40-2.95) and <28 (OR 2.24, 95%CI 1.45-3.47) weeks of gestation. Data on type of preterm birth was limited: one study showed a significant association of fibroids with spontaneous preterm birth and another with indicated preterm birth. The main limitations of the included studies were the lack of correction for confounders, the risk of ascertainment bias due to possible underreporting of fibroids, and the substantial heterogeneity between studies.

CONCLUSIONS

Our results suggest fibroids are associated with an increased risk of preterm birth, with a stronger risk at earlier gestational ages. We encourage further research to clarify the association between fibroids and preterm birth by systematic myometrial assessment in pregnancy.

REGISTRATION

Prospero database [CRD42020186976].

The Impact of Uterine Fibroids on Fertility: How the Uncertainty Widens the Gap in Reproductive Outcomes in Black Women

Uterine fibroids (UFs) are the most common pelvic tumor in women. While the decreased quality of life and significant morbidity has been implicated with UFs, several important questions regarding the effect of UFs on reproductive outcomes remain unanswered. Furthermore, there is a disproportionate impact of UFs in Black women, in whom these tumors are known to be more common and more severe. The racial difference in UF burden is heightened during prime reproductive years, during which Black women undergo surgical intervention at an astoundingly increased rate compared to other races. Despite this, Black women are underrepresented in UF and treatment outcome research, and thus the uncertainty of the impact of UFs and UF treatment on fertility and pregnancy outcomes in this population is less defined. The purpose of this review article is to discuss recent findings in the literature regarding the impact of uterine UFs on reproductive outcomes with a primary focus on the implications for Black women. Additionally, we briefly discuss the importance of increased UF research funding and investigation and propose actionable items to help increase the representation of Black women in UF research.