Maternal recurrent pregnancy loss is associated with an increased risk for long-term neurological morbidity in offspring

Association between urinary 2-hydroxyethyl mercapturic acid and dyslexia among school-aged children

Ethylene oxide is commonly used in industrial synthesis and medical disinfection. It is a known human carcinogen and has neurotoxicity. However, the association between ethylene oxide exposure and neurodevelopmental disorders remains unclear. This study aimed to evaluate the association between urinary concentrations of 2-hydroxyethyl mercapturic acid (HEMA; metabolite of ethylene oxide) and dyslexia among school-aged children. A total of 355 dyslexic children and 390 controls from three cities in China were enrolled in this case-control study from November 2017 to December 2020. Urinary HEMA was detected in 100% of the urine samples, suggesting widespread exposure to ethylene oxide in the children. Notably, the children with dyslexia had higher concentrations of urinary HEMA compared to the controls (geometric mean: 2.92 vs. 2.47 ng/mL) (P = 0.004). In the multivariable-adjusted model, urinary concentrations of HEMA were significantly associated with dyslexia risk. The individuals within the highest HEMA concentration demonstrated a 1.97-fold increased odds of dyslexia compared to those within the lowest quartile (95% confidence interval: 1.20-3.23). Thus, these findings suggested the possible link between HEMA levels and the risk of dyslexia. Further studies are warranted to validate this finding and illustrate the underlying mechanism.

Association of perchlorate, thiocyanate, and nitrate with dyslexic risk

Perchlorate, thiocyanate, and nitrate are sodium iodide symporter (NIS) inhibitors that disturb iodide uptake into the thyroid and have been implicated in child development. However, no data are available on the association between exposure to/related with them and dyslexia. Here, we examined the association of exposure to/related with the three NIS inhibitors with the risk of dyslexia in a case-control study. The three chemicals were detected in urine samples of 355 children with dyslexia and 390 children without dyslexia from three cities in China. The adjusted odds ratios for dyslexia were examined using logistic regression models. The detection frequencies of all the targeted compounds were 100%. After adjusting for multiple covariates, urinary thiocyanate was significantly associated with the risk of dyslexia (P-trend = 0.02). Compared with the lowest quartile, children within the highest quartile had a 2.66-fold risk of dyslexia (95% confidence interval: 1.32, 5.36]. Stratified analyses showed that the association between urinary thiocyanate level and the risk of dyslexia was more pronounced among boys, children with fixed reading time, and those without maternal depression or anxiety during pregnancy. Urinary perchlorate and nitrate levels were not associated with the risk of dyslexia. This study suggests the possible neurotoxicity of thiocyanate or its parent compounds in dyslexia. Further investigation is warranted to confirm our findings and clarify the potential mechanisms.

Association between previous abortion history and risk of autism spectrum disorders among offspring: a meta-analysis

BACKGROUND

Previous studies have been showed an association between previous abortion history and risk of Autism spectrum disorders (ASD). However, there is still controversy about true effect estimate of the association.

PURPOSE

This meta-analysis aimed to evaluate the association between previous abortion history and the risk of ASD.

METHODS

A systematic search was performed using PubMed, Scopus, and Web of Sciences databases to identify potential studies published until December 2021. The presence of statistical heterogeneity was determined using the I2 value. In the case of substantial heterogeneity, the random-effects model meta-analysis was used to estimate the pooled relative risks. The publication bias was assessed using the Egger and Begg tests.

RESULTS

Thirteen studies with a total of 331,779 children remained in the present meta-analysis. The estimated odds ratio of the risk of ASD associated with previous abortion history was 1.64 (95% confidence interval [CI], 1.28-2.0; I2=61.7%) in adjusted studies and 1.10 (95% CI, 1.01-1.20; I2=0.0%) in crude studies, based on the random effect model. There was moderate heterogeneity in adjusted studies. The p values for Egger and Begg regression among children with ASD were 0.393 and 0.056, respectively.

CONCLUSION

This meta-analysis suggests that children born from mothers with a history of previous abortion have an increased risk of development of ASD compared to children of mothers without a history of previous abortion.

Stem Cell-Based Trophoblast Models to Unravel the Genetic Causes of Human Miscarriages

Miscarriage affects approximately 15% of clinically recognized pregnancies, and 1-3% of couples experience pregnancy loss recurrently. Approximately 50-60% of miscarriages result from chromosomal abnormalities, whereas up to 60% of euploid recurrent abortions harbor variants in candidate genes. The growing number of detected genetic variants requires an investigation into their role in adverse pregnancy outcomes. Since placental defects are the main cause of first-trimester miscarriages, the purpose of this review is to provide a survey of state-of-the-art human in vitro trophoblast models that can be used for the functional assessment of specific abnormalities/variants implicated in pregnancy loss. Since 2018, when primary human trophoblast stem cells were first derived, there has been rapid growth in models of trophoblast lineage. It has been found that a proper balance between self-renewal and differentiation in trophoblast progenitors is crucial for the maintenance of pregnancy. Different responses to aneuploidy have been shown in human embryonic and extra-embryonic lineages. Stem cell-based models provide a powerful tool to explore the effect of a specific aneuploidy/variant on the fetus through placental development, which is important, from a clinical point of view, for deciding on the suitability of embryos for transfer after preimplantation genetic testing for aneuploidy.

Risk of intellectual disability and maternal history of spontaneous abortion: a nationwide cohort study

AIM

To investigate the association between a maternal history of spontaneous abortion and intellectual disability in children.

METHOD

This cohort study included 1 778 786 children (913 340 males, 865 085 females, 361 missing data; mean age 15y 2mo, SD 8y 11mo, range birth to 40y) born in Denmark between 1977 and 2016. Cox proportional hazard regression was used to estimate the hazard ratios (HRs) of intellectual disability.

RESULTS

The overall HR of intellectual disability for children with a maternal history of spontaneous abortion was 1.17 (95% confidence interval [CI] 1.12-1.22) and the risk for multiple spontaneous abortions (HR=1.30, 95% CI 1.20-1.40) was higher than for a single spontaneous abortion (HR=1.13, 95% CI 1.07-1.18). When only cases of inpatient intellectual disability were included, the estimates increased slightly: the overall HR was 1.22 (95% CI 1.12-1.32), the HR for multiple spontaneous abortions was 1.37 (95% CI 1.20-1.58), and the HR for a single spontaneous abortion was 1.17 (95% CI 1.07-1.28). The risks were similar regardless of whether spontaneous abortion occurred before or after the index delivery. Estimates were nearly unchanged after adjusting for preterm birth, low birthweight, or Apgar score.

INTERPRETATION

Children born to mothers with spontaneous abortion, especially multiple spontaneous abortions, may be at a higher risk of intellectual disability in later life, regardless of whether spontaneous abortion occurred before or after the index delivery. The findings have clinical implications for targeted early intervention of children with intellectual disability. What this paper adds A maternal history of spontaneous abortion was associated with a risk of intellectual disability in offspring. The risk was higher in children whose mothers previously had multiple spontaneous abortions. Similar risks were observed regardless of whether spontaneous abortion occurred before or after childbirth.

Maternal history of recurrent pregnancy loss and future risk of ophthalmic morbidity in the offspring

OBJECTIVE

The objective of the study was to investigate whether maternal history of recurrent pregnancy loss (RPL) is associated with offspring childhood ophthalmic morbidity.

METHOD

A hospital-based cohort analysis comparing long-term offspring ophthalmic morbidity in women with and without a history of RPL was performed. Ophthalmic morbidity included hospitalizations involving a pre-defined set of ICD-9 codes. Offspring with congenital anomalies, perinatal mortality cases, and multifetal pregnancies were excluded from the analysis. Cumulative morbidity incidence was compared using Kaplan-Meier survival curves, and the risk of long-term ophthalmic morbidity was assessed by Cox proportional hazards model after adjustment for confounders.

RESULTS

During the study period, 242,187 newborns met the inclusion criteria; 5% (12,182) of them were offspring born to mothers with a history of RPL. Ophthalmic morbidity was significantly more common in the RPL group (1.3% vs 0.9%, p < .001, Kaplan-Meier log-rank p < .001). Adjustment for confounders, such as maternal age, gestational age, hypertensive disorders, and maternal diabetes, using Cox regression found that being born to a mother with RPL was independently associated with long-term ophthalmic morbidity (adjusted HR 1.35, 95% CI 1.15-1.59, p < .001).

CONCLUSION

Being born to a mother with RPL is independently associated with an increased risk of ophthalmic morbidity.

Association of spontaneous abortion and Ureaplasma parvum detected in placental tissue

Spontaneous abortion is considered a public health problem having several causes, including infections. Among the infectious agents, bacteria of the vaginal microbiota and Ureaplasma parvum have been associated with abortion, but their participation needs to be further elucidated. This study aims to evaluate the influence of Mollicutes on the development of spontaneous abortion. Women who underwent spontaneous abortion and those with normal birth (control) were studied. Samples of cervical mucus (CM) and placental tissue were collected to identify Mollicutes using the quantitative polymerase chain reaction methodology. Eighty-nine women who had a miscarriage and 20 women with normal pregnancies were studied. The presence of Mollicutes in placental tissue increased the chance of developing miscarriage sevenfold. The prevalence of U. parvum in women who experienced spontaneous abortion was 66.3% in placental tissue. A positive association was observed between the detection of U. parvum in samples of placental tissue and abortion. There was a significant increase in microbial load in placental tissue for M. hominis, U. urealyticum and U. parvum compared to the control group. Detection of U. parvum in CM in pregnant women can ascend to the region of the placental tissue and trigger a spontaneous abortion.