Maternal history of recurrent pregnancy loss and long-term risk of thromboembolic events

Fetal loss and long-term maternal morbidity and mortality: A systematic review and meta-analysis

BACKGROUND

Evidence suggests common pathways between pregnancy losses and subsequent long-term maternal morbidity, rendering pregnancy complications an early chronic disease marker. There is a plethora of studies exploring associations between miscarriage and stillbirth with long-term adverse maternal health; however, these data are inconclusive.

METHODS AND FINDINGS

We systematically searched MEDLINE, EMBASE, AMED, BNI, CINAHL, and the Cochrane Library with relevant keywords and MeSH terms from inception to June 2023 (no language restrictions). We included studies exploring associations between stillbirth or miscarriage and incidence of cardiovascular, malignancy, mental health, other morbidities, and all-cause mortality in women without previous pregnancy loss. Studies reporting short-term morbidity (within a year of loss), case reports, letters, and animal studies were excluded. Study selection and data extraction were performed by 2 independent reviewers. Risk of bias was assessed using the Newcastle Ottawa Scale (NOS) and publication bias with funnel plots. Subgroup analysis explored the effect of recurrent losses on adverse outcomes. Statistical analysis was performed using an inverse variance random effects model and results are reported as risk ratios (RRs) with 95% confidence intervals (CIs) and prediction intervals (PIs) by combining the most adjusted RR, odds ratios (ORs) and hazard ratios (HRs) under the rare outcome assumption. We included 56 observational studies, including 45 in meta-analysis. There were 1,119,815 women who experienced pregnancy loss of whom 951,258 had a miscarriage and 168,557 stillbirth, compared with 11,965,574 women without previous loss. Women with a history of stillbirth had a greater risk of ischaemic heart disease (IHD) RR 1.56, 95% CI [1.30, 1.88]; p < 0.001, 95% PI [0.49 to 5.15]), cerebrovascular (RR 1.71, 95% CI [1.44, 2.03], p < 0.001, 95% PI [1.92, 2.42]), and any circulatory/cardiovascular disease (RR 1.86, 95% CI [1.01, 3.45], p = 0.05, 95% PI [0.74, 4.10]) compared with women without pregnancy loss. There was no evidence of increased risk of cardiovascular disease (IHD: RR 1.11, 95% CI [0.98, 1.27], 95% PI [0.46, 2.76] or cerebrovascular: RR 1.01, 95% CI [0.85, 1.21]) in women experiencing a miscarriage. Only women with a previous stillbirth were more likely to develop type 2 diabetes mellitus (T2DM) (RR: 1.16, 95% CI [1.07 to 2.26]; p < 0.001, 95% PI [1.05, 1.35]). Women with a stillbirth history had an increased risk of developing renal morbidities (RR 1.97, 95% CI [1.51, 2.57], p < 0.001, 95% [1.06, 4.72]) compared with controls. Women with a history of stillbirth had lower risk of breast cancer (RR: 0.80, 95% CI [0.67, 0.96], p-0.02, 95% PI [0.72, 0.93]). There was no evidence of altered risk of other malignancies in women experiencing pregnancy loss compared to controls. There was no evidence of long-term mental illness risk in women with previous pregnancy losses (stillbirth: RR 1.90, 95% CI [0.93, 3.88], 95% PI [0.34, 9.51], miscarriage: RR 1.78, 95% CI [0.88, 3.63], 95% PI [1.13, 4.16]). The main limitations include the potential for confounding due to use of aggregated data with variable degrees of adjustment.

CONCLUSIONS

Our results suggest that women with a history of stillbirth have a greater risk of future cardiovascular disease, T2DM, and renal morbidities. Women experiencing miscarriages, single or multiple, do not seem to have an altered risk.

Thyroglobulin Antibodies in Women with Recurrent Pregnancy Loss: A Systematic Review and Meta-Analysis

Background: Thyroid autoimmunity is the most prevalent autoimmune disorder among women of reproductive age and has been suggested as a risk factor in recurrent pregnancy loss (RPL)-a condition in which couples suffer several consecutive pregnancy losses, but where a cause can be identified in less than half of the cases. Most studies have focused on thyroid peroxidase antibodies (TPOAbs), not considering the presence of thyroglobulin antibodies (TgAbs). The aim of this study was to systematically assess the prevalence of TgAb positivity in women with RPL, and whether TgAb positivity was associated with the outcome of the next pregnancy. Methods: A systematic literature search of PubMed and Embase (from inception to April 29, 2023) was performed for studies reporting on TgAbs in women with RPL. The primary outcome was TgAb positivity in women with RPL compared with women without RPL, with a secondary outcome of association between TgAb positivity and the outcome of the next pregnancy. Pooled effect estimates were expressed as odds ratios (ORs) with confidence intervals [CI] using a random-effects model. The study was registered with PROSPERO (No. CRD42022310232) and adhered to the PRISMA guidelines. Results: A total of 770 studies were screened, 28 of which could be included reporting data from a total of 6868 women. The prevalence of TgAb positivity in women with RPL ranged from 3.6% to 28% compared with 2.4% to 29% in women without RPL. The OR for TgAb positivity was 1.93 ([CI 1.27-2.92]; I2 = 63%) compared with women without RPL, and for TgAbs and/or TPOAbs 2.66 ([CI 1.75-4.05]; I2 = 69%). Four studies reported on the outcome of the next pregnancy after antibody measurement with highly heterogeneous results (OR for pregnancy loss ranging from 0.99 in one study to 10.0 in the other study, and two studies reported no data eligible for meta-analysis). Consequently, a meta-analysis could not be performed. Conclusions: Women with RPL were significantly more often TgAb-positive than women without RPL. Although there was a lack of studies reporting prospective outcomes, the findings of this study support the significance of awareness about the strong association between RPL and thyroid autoimmunity.

Reproduction as a window to future health in women

Cultivating awareness for reproduction as a window to future health presents an opportunity for early identification and modification of risk factors that can affect both individual and population-level morbidity and mortality. Infertility could serve as both a window into future health as well as a pathway to future pathology. The underlying mechanisms of infertility may share common pathways with long-term risk for health and well-being. Making this identification early in the disease process may improve opportunities for intervention, and deepen our understanding of long-term risk. Additionally, fertility treatments may increase individual risk. Only by making these associations and designing studies to understand how disease and treatment risk impact health can we truly fulfill our goal of building healthy families. The aim of this review is to discuss the short-term impact of fertility challenges and treatment, long-term associations of infertility with morbidity and mortality, and the role of parity in modifying these risk associations.

Recurrent pregnancy loss

Recurrent pregnancy loss is a distressing pregnancy disorder experienced by ~2.5% of women trying to conceive. Recurrent pregnancy loss is defined as the failure of two or more clinically recognized pregnancies before 20-24 weeks of gestation and includes embryonic and fetal losses. The diagnosis of an early pregnancy loss is relatively straightforward, although progress in predicting and preventing recurrent pregnancy loss has been hampered by a lack of standardized definitions, the uncertainties surrounding the pathogenesis and the highly variable clinical presentation. The prognosis for couples with recurrent pregnancy loss is generally good, although the likelihood of a successful pregnancy depends on maternal age and the number of previous losses. Recurrent pregnancy loss can be caused by chromosomal errors, anatomical uterine defects, autoimmune disorders and endometrial dysfunction. Available treatments target the putative risk factors of pregnancy loss, although the effectiveness of many medical interventions is controversial. Regardless of the underlying aetiology, couples require accurate information on their chances of having a baby and appropriate support should be offered to reduce the psychological burden associated with multiple miscarriages. Future research must investigate the pathogenesis of recurrent pregnancy loss and evaluate novel diagnostic tests and treatments in adequately powered clinical trials.

Association between factor V Leiden mutation and recurrent pregnancy loss in the middle east countries: a Newcastle-Ottawa meta-analysis

PURPOSE

Heritable thrombophilia is a category of genetic disorders of the coagulation cascade with the increasing risk of thrombus formation and recurrent pregnancy loss (RPL). Factor V Leiden (FVL) (R506Q) mutation is the most common genetic cause of deep venous thrombosis, but its association with RPL has been inconsistent in studies arising from non-Western countries. The present metanalysis was aimed to determine whether an association exists between FVL and RPL in the Middle East.

METHODS

We searched PubMed, MEDLINE Web of Science, Scopus, and Embase, evaluating the association between the FVL and RPL. The Middle East countries (Bahrain, Cyprus, Egypt, Iran, Iraq, Israel, Jordan, Kuwait, Lebanon, Oman, Qatar, Saudi Arabia, The State  of Palestine, Syria, Turkey, The United Arab Emirates, and Yemen) were evaluated in succession. Raw data were extracted, and 19 case-control studies were included in our final analysis.

RESULTS

Overall, 2513 cases and 1836 controls in the Middle East showed a prevalence of FVL mutation as 12.6% and 4.9% in patients and controls, respectively. To evaluate the relationship between FVL mutation and RPL, we used Forest plot (random effect model) with the overall random OR of 2.37 (CI 95%: 1.50-3.75). FVL mutation was associated with a higher risk of RPL. In Iran, the OR was 1.90 (95% CI 1.04-3.45), and in Turkey, the OR was 3.01 (95% CI 1.10-8.23).

CONCLUSION

The results of our study support an association between FVL mutation status and RPL in women of the Middle East countries. It is recommended that specific policies include comprehensive testing for FVL mutation as a standard of care in women of the Middle East region with unexplained RPL.