Spontaneous abortion and endometriosis

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.

Endometriosis is associated with pregnancy loss: a nationwide historical cohort study

OBJECTIVE

To study whether endometriosis is associated with pregnancy loss and recurrent pregnancy loss (RPL).

DESIGN

Nationwide historical cohort study with a nested case-control analysis.

SETTING

National health registers.

PATIENT(S)

A total of 29,563 women born between 1957 and 1997 were identified in the national health registers, diagnosed with endometriosis between 1977 and 2017, and age-matched 1:10 with 295,630 women without endometriosis. The number of pregnancy losses was assessed, and data were analyzed with conditional logistic regression.

INTERVENTION(S)

Endometriosis (International Classification of Diseases, 8th Revision, 62530-62539, and International Classification of Diseases, 10th Revision, DN80.0-9).

MAIN OUTCOME MEASURE(S)

The primary outcomes of interest were the numbers of pregnancy losses categorized as 0, 1, 2, and ≥ 3 losses, unadjusted and adjusted for gravidity, and RPL. The secondary outcome measures were the predefined types of pregnancy losses. Pregnancy loss was defined as the spontaneous demise of a pregnancy until 22 weeks of gestation. Primary RPL was defined as 3 or more consecutive pregnancy losses with no prior live birth or stillbirth, and secondary RPL was defined as 1 or more births followed by 3 or more consecutive losses.

RESULT(S)

A total of 18.9%, 3.9%, and 2.1% of ever-pregnant women with endometriosis had 1, 2, and ≥ 3 pregnancy losses compared with 17.3%, 3.5%, and 1.5% of the women without endometriosis, corresponding to the odds ratios of 1.13 (95% confidence interval, 1.09-1.17), 1.18 (1.10-1.26), and 1.44 (1.31-1.59), respectively. When adjusted also for gravidity, the corresponding results were 1.37 (95% confidence interval, 1.32-1.42), 1.75 (1.62-1.89), and 2.57 (2.31-2.85), respectively. The following predefined subgroups of RPL were positively associated with endometriosis: primary; secondary; secondary after giving birth to a boy; after a complicated delivery; and ≥ 3 pregnancy losses before the age of 30 years. Six endometriosis subgroup analyses found an association between endometriosis and pregnancy loss. These analyses were women diagnosed in the 4 decades between 1977 and 2017, women with adenomyosis, and women with adenomyosis only.

CONCLUSION(S)

This nationwide cohort study found endometriosis to be associated with pregnancy loss and RPL, and the association strengthened with an increasing number of losses.

From Endometriosis to Pregnancy: Which is the “Road-Map”?

In the last decade, pregnancy was considered as a therapeutic period for patients affected by endometriosis and painful symptoms. However, several studies have taken into consideration how endometriosis affects pregnancy achievement and pregnancy development, including obstetric complications. The adverse effects of endometriosis on the development of pregnancy include miscarriage, hypertensive disorders and pre-eclampsia, placenta previa, obstetric hemorrhages, preterm birth, small for gestational age, and adverse neonatal outcomes. The aim of this review is to analyze the current literature regarding the relationship between different forms of endometriosis (endometrioma, peritoneal endometriosis, deep endometriosis) and infertility, and the impact of endometriosis on pregnancy outcomes.

A systematic review on endometriosis during pregnancy: diagnosis, misdiagnosis, complications and outcomes

BACKGROUND

Traditionally, pregnancy was considered to have a positive effect on endometriosis and its painful symptoms due not only to blockage of ovulation preventing bleeding of endometriotic tissue but also to different metabolic, hormonal, immune and angiogenesis changes related to pregnancy. However, a growing literature is emerging on the role of endometriosis in affecting the development of pregnancy and its outcomes and also on the impact of pregnancy on endometriosis. The present article aims to underline the difficulty in diagnosing endometriotic lesions during pregnancy and discuss the options for the treatment of decidualized endometriosis in relation to imaging and symptomatology; to describe all the possible acute complications of pregnancy caused by pre-existing endometriosis and evaluate potential treatments of these complications; to assess whether endometriosis affects pregnancy outcome and hypothesize mechanisms to explain the underlying relationships.

METHODS

This systematic review is based on material searched and obtained via Pubmed and Medline between January 1950 and March 2015. Peer-reviewed, English-language journal articles examining the impact of endometriosis on pregnancy and vice versa were included in this article.

RESULTS

Changes of the endometriotic lesions may occur during pregnancy caused by the modifications of the hormonal milieu, posing a clinical dilemma due to their atypical appearance. The management of these events is actually challenging as only few cases have been described and the review of available literature evidenced a lack of formal estimates of their incidence. Acute complications of endometriosis during pregnancy, such as spontaneous hemoperitoneum, bowel and ovarian complications, represent rare but life-threatening conditions that require, in most of the cases, surgical operations to be managed. Due to the unpredictability of these complications, no specific recommendation for additional interventions to the routinely monitoring of pregnancy of women with known history of endometriosis is advisable. Even if the results of the published studies are controversial, some evidence is suggestive of an association of endometriosis with spontaneous miscarriage, preterm birth and small for gestational age babies. A correlation of endometriosis with placenta previa (odds ratio from 1.67 to 15.1 according to various studies) has been demonstrated, possibly linked to the abnormal frequency and amplitude of uterine contractions observed in women affected. Finally, there is no evidence that prophylactic surgery would prevent the negative impact of endometriosis itself on pregnancy outcome.

CONCLUSIONS

Complications of endometriosis during pregnancy are rare and there is no evidence that the disease has a major detrimental effect on pregnancy outcome. Therefore, pregnant women with endometriosis can be reassured on the course of their pregnancies although the physicians should be aware of the potential increased risk of placenta previa. Current evidence does not support any modification of conventional monitoring of pregnancy in patients with endometriosis.

Serum antiendometrial antibodies and diagnosis of endometriosis

PROBLEM

The purpose of the present prospective multi-center study is to investigate the relationship between laparoscopic diagnosis of endometriosis and results of a serum antiendometrial antibody (AEA) assay.

METHOD OF STUDY

Indirect immunofluorescence detection of AEA was performed on serum specimens from patients presenting with dysmenorrhea or chronic pelvic pain and infertility (n = 2609) utilizing frozen sections of endometrium acquired on cycle days 18-21 from normally cycling women without endometriosis. Diagnostic laparoscopy was performed within 1 year of AEA assay on 527 tested women.

RESULTS

The relationship between the serum AEA and laparoscopic verification was characterized by a positive predictive value = 88%, negative predictive value = 86%, sensitivity = 87% and specificity = 87%.

CONCLUSION

The AEA assay is a very good screening test for patients suspected of having endometriosis and should be utilized prior to laparoscopy in diagnostic categories of dysmenorrhea or chronic pelvic pain and infertility.

Endometriosis, recurrent miscarriage and implantation failure: is there an immunological link?

Endometriosis is more frequently diagnosed in patients with infertility than in a normal population. The goal of this paper is to give an overview of the clinical and fundamental evidence for a possible link between endometriosis and (recurrent) miscarriage or implantation failure after treatment with assisted reproductive technology. According to the literature, there is insufficient evidence for an association between endometriosis and (recurrent) miscarriage, but there is, however, epidemiological evidence to support the link between endometriosis and recurrent implantation failure after assisted reproduction. This can possibly be explained by alterations in humoral and cell-mediated immunity in women with endometriosis. Humoral immunological changes include increased formation of antibodies against endometrial antigens, anti-laminin-1 auto-antibodies and other auto-immune antibodies (e.g. antiphospholipid). Cell-mediated immunological changes include alterations in peritoneal and follicular fluid immune cells and cytokines. The possible negative effect of these immunological changes on folliculogenesis, ovulation, oocyte quality, early embryonic development and implantation in women with endometriosis suggests that infertility in endometriosis patients may be related to alterations within the follicle or oocyte, resulting in embryos with decreased ability to implant.

Endometriosis and infertility: a multi-cytokine imbalance versus ovulation, fertilization and early embryo development

Endometriosis is tightly linked to infertility which is manifested at very early or more advanced stages of the gestational cycle. Alteration on the production of a great number of cytokines/growth factors can be accused for problems on ovum maturation, fertilization or implantation. Yet, macroscopically these stages are characterized by the inability of conception. A closer look of the cytokinic profile during the conceptional and early gestational cycle could, however, localize the problem and allow a therapeutic approach. In this commentary, going through the cytokine requirement during ovulation, fertilization and the early stages of pregnancy, it became possible to specifically define the harmful endometriosis-induced cytokines for each of the conceptional and early gestational stages. Thus, regulating the levels of interferon-γ and tumor necrosis-α will facilitate ovulation and fertilization, whereas adjusting the levels of interleukin-1β and colony stimulating gactor-1 will facilitate implantation.

Endometriosis and spontaneous abortion rate: a cohort study in infertile women

OBJECTIVE

To ascertain if there is an association between endometriosis and spontaneous abortion.

DESIGN

Prospective cohort study.

SETTING

Medical School Hospital.

POPULATION

174 infertile women laparoscopically diagnosed with endometriosis and 174 infertile women in which endometriosis was ruled out by laparoscopy, in the same period of time.

MAIN OUTCOME MEASURE

Spontaneous abortion. Non-progressive gestational sac and/or histological study.

RESULTS

Per woman abortion rate was 7.47% (13/174) in the endometriosis group, similar to 5.74% (10/174) in the infertile women without endometriosis (RR=1.32: CI=0.53-3.36). Nor were there any differences in the per pregnancy abortion rate: 20.96% (13/62) in endometriosis vs. 16.94% (10/59) in non-endometriosis (RR=1.3; CI=0.47-3.57). The abortion rate was similar in the different AFS stages: 22.86% (8/35) in stage I, 16.67% (3/18) in II, 25% (1/4) in III and 20% (1/5) in IV. In stage I no differences were observed in patients who were managed expectantly or with medical treatment.

CONCLUSION

Endometriosis is not associated with an increased abortion rate. The severity of disease expressed by AFS staging is not associated with an increase in the abortion rate. In stage I the treatment of endometriosis did not decrease abortion rates.

Epidemiology of endometriosis in infertile women

OBJECTIVE

To assess the epidemiological factors linked to endometriosis in infertile women.

SETTING

Academic tertiary hospital.

DESIGN

Case-control study.

PATIENTS

One hundred seventy-four infertile women with endometriosis and 174 infertile women without endometriosis, all of them studied by laparoscopy.

RESULTS

Women with endometriosis and infertility had a higher frequency of cycles < or = 27 days (26.4% versus 16.7%). A trend to a protective effect of smoking was detected. Social class, reproductive history, infertility history, previous abortions, age, family history, age at menarche, and duration of menstrual flow were similar in both groups.

CONCLUSION

Cycles < or = 27 days was the only risk factor that seemed to be associated to endometriosis in infertile patients. However, predictive values were low. A trend to a protective effect of smoking was detected.

The impact of long-term gonadotropin-releasing hormone analogue treatment on preclinical abortions in patients with severe endometriosis undergoing in vitro fertilization-embryo transfer

OBJECTIVE

To examine the relationship between endometriosis and preclinical abortions and to evaluate the effect of gonadotropin-releasing hormone analogue (GnRH-a) therapy on these pregnancies.

DESIGN AND PATIENTS

Of 67 women with severe endometriosis referred to us for in vitro fertilization-embryo transfer (IVF-ET), 32 underwent ovarian stimulation for oocyte retrieval with menotropins (protocol A), whereas the other 35 were admitted for the procedure after a 6-month period of hormonal suppression with a GnRH agonist (protocol B). The clinical impact of the preclinical and clinical pregnancies in both treatment protocols were evaluated on the basis of oocyte classification and embryo quality score.

SETTING

All patients were treated in our IVF Unit.

MAIN OUTCOME MEASURE

Clinical pregnancy was used as our main outcome measure of success.

RESULTS

A significantly higher number of preclinical pregnancies (P less than 0.0001) occurred in patients treated by protocol A. After GnRH-a treatment, the preclinical pregnancy rate declined significantly (P less than 0.0001), whereas the clinical pregnancy rate per cycle and per transfer rose significantly (P less than 0.0001 and P less than 0.0001, respectively). Furthermore, clinical pregnancies had a significantly better mean embryo quality score in comparison with preclinical pregnancies (P less than 0.0001).

CONCLUSIONS

It is concluded that combining GnRH-a therapy before IVF-ET provides an improved treatment modality for preclinical abortions and infertility associated with severe endometriosis.

Spontaneous abortions in women with endometriosis

Pregnancy outcomes were evaluated retrospectively in 350 women to investigate the relationship between endometriosis and spontaneous abortions. The frequency of spontaneous abortions in women with endometriosis was significantly higher than in both a fertile nonendometriosis group and an infertile group with tubal disease. There was no correlation between the severity of the endometriosis and the frequency of spontaneous abortions. After treatment, the frequency of spontaneous abortions was significantly decreased in both the endometriosis and the tubal disease group, but these values were not significantly different from each other. We conclude that high spontaneous abortion rates are a characteristic of other subgroups of women with secondary infertility and not just in women with endometriosis, and that the majority of spontaneous abortions associated with endometriosis are not caused by the condition.

Preclinical abortions and endometriosis

A single human chorionic gonadotropin determination was performed in 786 infertile women during the late luteal phase to determine the frequencies of preclinical abortions and whether the frequency was increased in women with endometriosis. Thirty-seven pregnancies (4.7% of cycles) were identified, of which six were classified as preclinical abortions (0.8%). In women with endometriosis, the frequency of preclinical abortions was 0.9% and was not statistically different from other infertile subgroups. This study suggests that preclinical abortions are not cause of infertility in either an infertile population as a whole or in the subgroup of women with endometriosis.