Predictors of miscarriage: a matched case-control study

Understanding Miscarriage Prevalence and Risk Factors: Insights from Women in Jordan

Background and Objectives: Miscarriage is a complication that is influenced by many risk factors that have been reported in different studies and that vary among countries. Despite the influence of various known risk factors for miscarriage, 30% to 50% of miscarriages are from unidentified causes. The aim of this study is to determine the prevalence of miscarriages in Jordan and the associated risk factors. Materials and Methods: A cross-sectional online survey was conducted in Jordan among married women to investigate the prevalence of miscarriages and identify potential risk factors. Results: Women (n = 704) were surveyed, and 17.9% reported a history of miscarriage. The identified risk factors were being an active smoker during pregnancy, having more than four children, having a family history of miscarriage, having fertility problems, receiving medical assistance for conception, and traveling by air during pregnancy. Conclusions: The results suggest that there are both modifiable and non-modifiable risk factors for miscarriages in Jordan and that a proportion of these may be preventable. The findings can be used to enhance patient awareness and inform policy development to decrease the incidence of miscarriage in the country.

[Anti-endothelial cell antibodies in predicting early miscarriage]

OBJECTIVE

To explore the clinical significance of anti-endothelial cell antibodies (AECA) in predicting early miscarriage.

METHODS

A total of 122 pregnant women with no history of autoimmune diseases who underwent prenatal examination at Peking University People's Hospital from January 2020 to December 2022 were selected, and they were tested for AECA. Based on the history of early miscarriage (gestational age at miscarriage < 12 weeks), the participants were divided into an early miscarriage group and a control group. t-tests, non-parametric Wilcoxon tests, Chi-square tests, and Fisher's exact probability method were used to compare general information and laboratory indicators between the two groups. A multivariate Logistic regression model was used to analyze the factors associated with early miscarriage. The natural miscarriage rates were assessed through follow-up with pregnant women, and Kaplan-Meier survival analysis was employed to compare the natural miscarriage rates between AECA-positive and AECA-negative pregnant women.

RESULTS

(1) A total of 122 pregnant women were enrolled, comprising 35 cases (28.7%) in the early miscarriage group, with an average age of (32.1±6.1) years, and 87 cases (71.3%) in the control group, with an average age of (30.7±5.1) years. The early miscarriage group had higher gravidity [3 (2, 4) vs. 1 (1, 2), Z=-6.402, P < 0.001] and a higher prevalence of hypertension (11.4% vs.1.1%, P=0.024). The positive rate of AECA in the early miscarriage group (34.3% vs. 8.0%, χ2=13.070, P < 0.001) and the proportion of elevated immunoglobulin G (17.1% vs. 4.6%, P=0.032) were significantly higher than that in the control group. (2) Multivariate logistic regression analysis showed that higher gravidity (OR=4.149, 95%CI: 2.287-7.529, P < 0.001), AECA positivity (OR= 4.288, 95% CI: 1.157-15.893, P=0.029), and elevated immunoglobulin G levels (OR =6.177, 95%CI: 1.156-33.015, P=0.033) were risk factors for early miscarriage. (3) The 122 pregnant women were categorized into two groups: the AECA-positive group (19 cases) and the AECA-negative group (103 cases). Survival analysis demonstrated that at the end of 12 weeks of gestation, the fetal survival rate in the AECA-positive group was significantly lower than that in the AECA-negative group (84.2% vs. 96.1%, P= 0.035).

CONCLUSION

Higher gravidity, AECA positivity, and elevated immunoglobulin G levels are significant risk factors for early miscarriage. The results demonstrate that AECA is a novel predicting test in early miscarriage.

Gestational lead exposure and its effects on fetal/infant development - A systematic review

Studies suggest that gestational exposure to lead (Pb) is related to spontaneous abortions, preterm birth, lower infant birth weight and length, and neurological dysfunctions. However, the evidence about its effects during pregnancy exposure on fetal and child development is still poor. Thus, the aim of this systematic review was to verify the association between prenatal exposure to Pb and the occurrence of neurobehavioral deficits, miscarriages, and child mortality. Observational studies with pregnant women exposed to Pb during pregnancy were included, without gender or ethnicity restrictions. The MEDLINE, Cochrane Library, EMBASE, Scopus, Web of Science, and LILACS databases were searched. The reading of titles and abstracts was conducted, followed by reading in full format and data extraction, that were performed independently by two reviewers. The included studies were evaluated by Downs and Black tool and qualitatively synthesized. Certainty of evidence was assessed by Grading of Recommendations Assessment, Development, and Evaluations (GRADE). The study protocol was registered with the Prospective Registry of Systematic Reviews (PROSPERO; CRD42022296750). Among twenty-one studies included, sixteen were classified as prospective cohort, two case-control, one nested case-control, one cohort, and one longitudinal study. No study that evaluated child mortality associated with gestational Pb exposure was found. There is a very low certainty of evidence in the association of gestational Pb exposure and neurobehavioral deficits or miscarriages. This systematic review reflects the poor evidence and the challenges of human toxicology studies, since it was not possible to associate gestational Pb exposure to neurobehavioral deficits, miscarriages, and child mortality.

A Validation Study on the Frequency and Natural History of Miscarriages Using the Spanish Primary Care Database BIFAP

(1) Background: There is a major gap of knowledge towards the natural history of miscarriages in electronic medical records. We aimed to calculate the frequency of miscarriages using data from BIFAP database. (2) Methods: We identified all pregnancy losses and carried out a multistep validation exercise. Potential cases with positive predictive values (PPV) of miscarriage confirmation <85% or those confirming other pregnancy loss were excluded. Kaplan–Meier figures and incidence rates (IRs) of miscarriage with 95% confidence intervals (CIs) expressed by 1000 person-weeks were calculated. Stratifying analysis by age, specific high-risk groups, and drug exposure within the pre-pregnancy period were performed restricted to women with recording last menstrual period (LMP). (3) Results: Women with confirmed miscarriage (N = 18,070), tended to be older, with higher frequency of comorbidities and drug utilization. Restricting to women with LPM recorded, IR of miscarriage was 10.89 (CI 95% 10.68–11.10) per 1000 women-weeks, with a median follow-up of 10 weeks (IQR: 8–12). The IR according to age was: 2.71 (CI 95% 2.59–2.84) in those aged <30 years compared to 9.11 (CI 95% 8.55–9.70) in women aged ≥40 years. Advanced maternal age (Hazard Ratio (HR, 95% confidence interval) CI 95%: 3.34 (3.08–3.62)), use of antihypertensives (1.49 (1.21–1.84), and use of drugs classified as D or X during pregnancy (1.17 (1.07–1.29)) showed to be positive predictors associated with increased risk of miscarriages. (4) Conclusion: BIFAP database can be used to identify women suffering from miscarriages, which will serve to further study risk factors associated with miscarriages with special attention to drug utilization.

Pregnancy Loss in Women with HIV is not Associated with HIV Markers: Data from a National Study in Italy, 2001-2018

Background

There is limited information on pregnancy loss in women with HIV, and it is still debated whether HIV-related markers may play a role.Objectives: To explore potential risk factors for pregnancy loss in women with HIV, with particular reference to modifiable risk factors and markers of HIV disease.

Methods

Multicenter observational study of HIV-positive pregnant women. The main outcome measure was pregnancy loss, including both miscarriage (<22 weeks) and stillbirth (≥22 weeks). Possible associations of pregnancy loss were evaluated in univariate and multivariate analyses.

Results

Among 2696 eligible pregnancies reported between 2001 and 2018, 226 (8.4%) ended in pregnancy loss (miscarriage 198, 7.3%; stillbirth 28, 1.0%). In multivariate analyses, only older age (adjusted odds ratio [AOR] per additional year of age: 1.079, 95% confidence interval [CI] 1.046-1.113), HIV diagnosis before pregnancy (AOR: 2.533, 95%CI 1.407-4.561) and history of pregnancy loss (AOR: 1.625, 95%CI 1.178-2.243) were significantly associated with pregnancy loss. No significant association with pregnancy loss was found for parity, coinfections, sexually transmitted diseases, hypertension, smoking, alcohol and substance use, CD4 cell count, HIV-RNA viral load, and CDC HIV stage.

Conclusions

Older women and those with a previous history of pregnancy loss should be considered at higher risk of pregnancy loss. The severity of HIV disease and potentially modifiable risk factors did not increase the risk of pregnancy loss.

Complications in Early Pregnancy

Early in pregnancy women frequently experience nausea, vomiting, and vaginal bleeding. Nausea and vomiting can be mild, managed by dietary modifications and medications, or severe, requiring intravenous fluids and medications. Care should be used when selecting medications for nausea to avoid additional side effects or potential harm to the developing fetus. When evaluating vaginal bleeding in early pregnancy, ectopic pregnancy must be ruled out. If an intrauterine pregnancy is seen, threatened miscarriage should be considered and the patient appropriately counseled. If neither intrauterine pregnancy nor ectopic pregnancy can be established, a management algorithm for pregnancy of unknown location is presented.

Epidemiological Survey and Risk Factor Analysis of Recurrent Spontaneous Miscarriages in Infertile Women at Large Infertility Centers

Background:

A higher frequency of spontaneous miscarriage has been observed in infertile couples, and there is a higher prevalence of infertility among patients with a history of recurrent spontaneous miscarriages (RSMs; ≥2 miscarriages). This study aimed to determine the proportion of infertile patients with RSM and examine risk factors associated in patients with RSM being treated with assisted reproductive technologies.

Methods:

This cross-sectional observational study was conducted at six reproductive medicine centers in three cities of China. Data of 751 patients with at least one spontaneous miscarriage were analyzed. Demographic data and etiological factors associated with infertility were compiled and compared between patients with a single spontaneous miscarriage (SSM) and those with RSM.

Results:

Two hundred (26.6%, 95% confidence interval [CI]: 23.50–29.95%) patients experienced RSMs and 551 (73.4%) had a single miscarriage. The odds of RSM increased with increasing age (odds ratio [OR] = 1.06), uterine disorders (OR = 2.09), endocrine disorders (OR = 2.48), and immune disorders (OR = 2.98). Higher education level, masters or above, and a pelvic cavity disorder were associated with lower risk of RSM (OR = 0.27 and 0.46, respectively). Late spontaneous miscarriages were more frequent in patients with RSM than in those with a SSM (31.5% vs. 14.2%, respectively, P < 0.001) and were associated with a history of uterine cavity procedures (OR = 2.095) and cervical factors related to infertility (OR = 4.136, 95% CI: 1.012–16.90).

Conclusions:

Compared to patients with only a SSM, the conditions of patients with RSM are more complicated. To increase the success rate of assisted reproductive technology, factors including uterus cavity adhesion, cervical relaxation, endocrine disorders, and immune disorders should be treated before assisted reproduction is initiated. These data may provide treatment guidance for infertile patients with a history of RSM.

Preconception Blood Pressure Levels and Reproductive Outcomes in a Prospective Cohort of Women Attempting Pregnancy

Elevated blood pressure in young adulthood is an early risk marker for cardiovascular disease. Despite a strong biological rationale, little research has evaluated whether incremental increases in preconception blood pressure have early consequences for reproductive health. We evaluated preconception blood pressure and fecundability, pregnancy loss, and live birth in the EAGeR trial (Effects of Aspirin on Gestational and Reproduction; 2007-2011), a randomized clinical trial of aspirin and reproductive outcomes among 1228 women attempting pregnancy with a history of pregnancy loss. Systolic and diastolic blood pressure were measured during preconception in the first observed menstrual cycle and in early pregnancy and used to derive mean arterial pressure. Fecundability was assessed as number of menstrual cycles until pregnancy, determined through human chorionic gonadotropin testing. Pregnancy loss included both human chorionic gonadotropin-detected and clinical losses. Analyses adjusted for treatment assignment, age, body mass index, race, marital status, smoking, parity, and time since last loss. Mean preconception systolic and diastolic blood pressure were 111.6 mm Hg (SD, 12.1) and 72.5 (SD, 9.4) mm Hg. Risk of pregnancy loss increased 18% per 10 mm Hg increase in diastolic blood pressure (95% confidence interval, 1.03-1.36) and 17% per 10 mm Hg increase in mean arterial pressure (95% confidence interval, 1.02-1.35) in adjusted analyses. Findings were similar for early pregnancy blood pressure. Preconception blood pressure was not related to fecundability or live birth in adjusted analyses. Findings suggest that preconception blood pressure among healthy women is associated with pregnancy loss, and lifestyle interventions targeting blood pressure among young women may favorably impact reproductive health.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00467363.

Systematic review and meta-analysis on the association of prepregnancy underweight and miscarriage

BACKGROUND

Maternal underweight, overweight and obesity have been associated with a higher risk of miscarriage. Most individual reports and all meta-analyses have addressed high body mass index.

OBJECTIVES

To review the literature and summarize the risk of miscarriage in underweight women vs those with normal weight.

METHODS

A Medline Search (1st January 1990-20th November 2015, human, in English, French, Italian, Spanish or Portuguese) was conducted. Both spontaneous pregnancies and pregnancies after assisted reproduction techniques were considered. Cohort and case control studies were included if they reported data on the outcome of interest (clinical miscarriage), in underweight and normal weight women. Information on clinical miscarriage in other body mass index categories was collected when available. Two investigators reviewed the abstracts, full text papers and extracted data. Review Manager 5.1 software was used to summarize the results.

RESULTS

32 studies (30 cohort, 2 case control) and a total of 265,760 women were included. In cohort studies, the relative risk (RR) of clinical miscarriage in underweight women was 1.08, 95% CI 1.05-1.11; p<0.0001). The corresponding figures were RR 1.09, 95% CI 1.04-1.13; p<0.0001 for overweight women and RR 1.21, 95% CI 1.15-1.27; p<0.00001 for obese women. In case control studies, the odds ratio (OR) of clinical miscarriage in underweight women was 1.02, 95% CI 0.46-2.30; p=0.95). The corresponding figures were OR 1.01, 95% CI 0.88-1.16; p=0.89 for overweight women and OR 1.26, 95% CI 1.01-1.57; p=0.04 for obese women. The limitations of this study are that it is restricted to studies with information on underweight women and that I² ranges from 0 to 91% in different subgroups.

CONCLUSION

We conclude that maternal underweight is associated with a slightly increased risk of clinical miscarriage, similar to that of overweight women and lower than the risk observed in obesity. The heterogeneity displayed in some subgroups limits the strength of the conclusion.