Maternal self-reported genital tract infections during pregnancy and the risk of selected birth defects

Neural crest E-cadherin loss drives cleft lip/palate by epigenetic modulation via pro-inflammatory gene-environment interaction

Gene-environment interactions are believed to play a role in multifactorial phenotypes, although poorly described mechanistically. Cleft lip/palate (CLP), the most common craniofacial malformation, has been associated with both genetic and environmental factors, with little gene-environment interaction experimentally demonstrated. Here, we study CLP families harbouring CDH1/E-Cadherin variants with incomplete penetrance and we explore the association of pro-inflammatory conditions to CLP. By studying neural crest (NC) from mouse, Xenopus and humans, we show that CLP can be explained by a 2-hit model, where NC migration is impaired by a combination of genetic (CDH1 loss-of-function) and environmental (pro-inflammatory activation) factors, leading to CLP. Finally, using in vivo targeted methylation assays, we demonstrate that CDH1 hypermethylation is the major target of the pro-inflammatory response, and a direct regulator of E-cadherin levels and NC migration. These results unveil a gene-environment interaction during craniofacial development and provide a 2-hit mechanism to explain cleft lip/palate aetiology.

Maternal Common Cold or Fever During Pregnancy and the Risk of Orofacial Clefts in the Offspring: A Systematic Review and Meta-analysis

The common cold and/or an associated fever during pregnancy have/has been suspected to harm the developing fetus. We sought possible correlations between a maternal common cold or fever during pregnancy and the risk of orofacial clefts in the offspring.

We systematically searched PubMed and Embase using appropriate keywords, and we checked the reference lists of retrieved articles. We used random-effects models to estimate overall relative risks.

Incidence of orofacial clefts.

We included 13 case-control studies. Modest but statistically significant associations were found between a maternal common cold and cleft lip with or without a cleft palate (CL/CP) (odds ratio [OR] 2.17; 95% confidence interval [CI] 1.66-2.83) and a cleft palate only (CPO) (OR 3.08; 95% CI 1.5-6.34). Furthermore, maternal fever was also associated with an increased risk of CL/CP (OR 1.91, 95% CI 1.3-2.8) and CPO (OR 1.48, 95% CI 0.83-2.63) in the offspring. Further analyses of maternal influenza (alone) yielded similar results.

Although evidence of heterogeneity should be carefully evaluated, our findings suggest that maternal common cold or fever during pregnancy may be associated with a greater risk of CL/CP or CPO in the offspring. Future cohort studies using valid assessments of maternal common cold exposure during pregnancy that consider the severity of fever are needed to clarify the contribution of maternal common cold or fever status to the risk of orofacial clefts in children.

Association between maternal infections during pregnancy and congenital defects in their offspring: a population-based case-control study in Bogota and Cali, Colombia 2001-2018

Infections are frequent during pregnancy and their teratogenic role is well documented in Toxoplasmosis, other infections, Rubella, Cytomegalovirus, and Herpes simplex (TORCH). However, the in-utero development effects of the rest of the infections that affect pregnant women are unknown. We described a cohort of patients with major Birth Defects (BD) and the exposure to infections during pregnancy from the information of Congenital Defects Surveillance Programs of two Colombian cities (Bogota and Cali) between 2001 and 2018. We evaluated associations between groups of maternal infections and BD among 3096 cases and 7446 controls that were registered. BD presentation was more frequent as isolated (64.3%), polymalformed (23.2%), and syndromic (12.4%). Infections during pregnancy were present in 52.5% of cases and 44.6% of controls. The most common single infection between cases and controls was vaginal infection. The most common polyinfection was vaginal and urinary tract infection. We found an association between BD and vaginal infections with an odds ratio (OR) 1.18 (CI 1.08-1.30), urinary tract infections OR 1.16 (CI 1.05-1.28), gastrointestinal infections OR 2.06 (IC 1.18-3.59), respiratory infections OR 1.56 (IC 1.28-1.9) and viral infections OR 1.88 (IC 1.18-3.0). Knowing the teratogenic effect of infections is important to extend prevention, screening, timely diagnosis, and appropriate treatment to pregnant women.

Role of Maternal Infections and Inflammatory Responses on Craniofacial Development

Pregnancy is a tightly regulated immunological state. Mild environmental perturbations can affect the developing fetus significantly. Infections can elicit severe immunological cascades in the mother's body as well as the developing fetus. Maternal infections and resulting inflammatory responses can mediate epigenetic changes in the fetal genome, depending on the developmental stage. The craniofacial development begins at the early stages of embryogenesis. In this review, we will discuss the immunology of pregnancy and its responsive mechanisms on maternal infections. Further, we will also discuss the epigenetic effects of pathogens, their metabolites and resulting inflammatory responses on the fetus with a special focus on craniofacial development. Understanding the pathophysiological mechanisms of infections and dysregulated inflammatory responses during prenatal development could provide better insights into the origins of craniofacial birth defects.

Nongenetic risk factors for infantile cataracts: Systematic review of observational studies

INTRODUCTION

While infantile cataracts are a major cause of childhood blindness, risk factors remain unknown for approximately two-thirds of cases.

METHODS

We systematically searched electronic databases PubMed, Ovid MEDLINE, Web of Science, and Scopus, from inception through March 2018, to identify relevant cohort, case-control, cross-sectional studies, case reports, and case series. We also manually screened bibliographies and consulted with experts in the field to identify additional publications. We reviewed cross-sectional studies, case reports, and case series and provided a narrative summary of the reported potential risk factors. We evaluated methodological qualities of cohort and case-control studies, extracted relevant data, and described statistically significant associations with infant, maternal, and paternal characteristics. Quality assessment and data extraction were conducted by two reviewers independently. All discrepancies were discussed with the senior author and resolved by consensus.

RESULTS

Overall, 110 publications were included in the review, 33 of which were cohort and case-control studies. Most of these studies (n = 32) used population-based data and had either excellent (n = 31) or good (n = 2) methodological quality. Nine studies reported statistically significant associations with infant characteristics (preterm birth, low birth weight), maternal occupations and diseases during pregnancy (untreated hypertension, infections), and paternal sociodemographics (younger age, employment in sawmill industry during pregnancy).

CONCLUSIONS

This systematic literature review provided a comprehensive summary of the known nongenetic risk factors for infantile cataracts, identified gaps in the literature, and provided directions for future research. Studies identifying modifiable risk factors are warranted to design interventions aimed at primary prevention of infantile cataracts.

Maternal exposure to sulfonamides and adverse pregnancy outcomes: A systematic review and meta-analysis

Background

Sulfonamides are widely used to treat infectious diseases during pregnancy. However, the safety of maternal exposure to sulfonamides is controversial. This study aims to systematically review the available studies and examine the effect of maternal sulfonamides use on adverse pregnancy outcomes.

Methods

We searched PubMed, Science Direct, Web of Science, ClinicalTrials.gov, CNKI and Wanfang Database (in Chinese). The meta-analysis used random effects model or fixed effects model to obtain the total odds ratio (OR) for each outcome through Stata11.0 software. Study on the relationship between sulfonamide exposure during pregnancy and adverse pregnancy outcomes. The study design covered randomized controlled trials, cohort studies and case-control studies. The study protocol was registered in PROSPERO with protocol number CRD42020178687.

Results

A total of 10 studies, and 1096350 participants were included for systematic review. Maternal exposure to sulfonamides was found to be possibly associated with increased risk of congenital malformations (OR = 1.21, 95% CI 1.07–1.37). The use of sulfonamides in the first trimester of pregnancy and during the entire pregnancy might be associated with congenital malformations.

Conclusions

Maternal exposure to sulfonamides may be associated with offspring’ s congenital malformations. Prescription of sulfonamides for pregnant women is suggested to be carefully censored.

Sexually transmitted infections in pregnancy - An update on Chlamydia trachomatis and Neisseria gonorrhoeae

Routine screening for Chlamydia and gonococcal infection in pregnancy is not widespread, especially in low- and middle-income countries (LMICs), despite their potential adverse consequences on pregnancy outcome. We conducted a systematic literature search of three major databases to review current literature surrounding Chlamydia trachomatis and Neisseria gonorrhoeae infections in pregnancy. We discuss the epidemiology and burden of both infections, detection methods, potential adverse feto-maternal and infant outcomes and provide an overview of treatment options. A total of 67 articles met the inclusion criteria. The prevalence of C. trachomatis and N. gonorrhoeae across all trimesters ranged between 1.0%-36.8% and 0-14.2% worldwide, respectively. The most common diagnostic method is the Nucleic acid amplification test (NAAT). In pregnancy, chlamydia is associated with preterm birth, spontaneous miscarriage, stillbirth and neonatal conjunctivitis, while gonorrhoea is mainly associated with preterm birth and stillbirth. Amoxicillin, erythromycin and azithromycin showed similar efficacy in the treatment of chlamydia in pregnancy, while ceftriaxone and cefixime were effective in treating gonorrhoea in pregnancy. Being largely asymptomatic infections in women, we opine that detection strategies with locally appropriate tools should be combined with the syndromic approach in LMICs, where there is a high burden of disease.

Maternal genitourinary infections and risk of birth defects in the National Birth Defects Prevention Study

BACKGROUND

Genitourinary infections (GUIs) are common among sexually active women. Yet, little is known about the risk of birth defects associated with GUIs.

METHODS

Using data from the National Birth Defects Prevention Study, a multisite, population-based, case-control study, we assessed self-reported maternal GUIs in the month before through the third month of pregnancy (periconception) from 29,316 birth defect cases and 11,545 unaffected controls. We calculated odds ratios (ORs) and 95% confidence intervals to estimate the risk of 52 major structural birth defects associated with GUIs. We also calculated risk of birth defects associated with each type of GUI: urinary tract infection (UTI) and sexually transmitted infection (STI).

RESULTS

In our analysis, 10% (n = 2,972) of case and 9% (n = 1,014) of control mothers reported a periconceptional GUI. A GUI was significantly associated with 11 of the 52 birth defects examined (ORs ranging from 1.19 to 2.26): encephalocele, cataracts, cleft lip, esophageal atresia, duodenal atresia/stenosis, small intestinal atresia/stenosis, colonic atresia/stenosis, transverse limb deficiency, conoventricular septal defect, atrioventricular septal defect, and secundum atrial septal defect. A periconceptional UTI was significantly associated with nine birth defects (ORs from 1.21 to 2.48), and periconceptional STI was significantly associated with four birth defects (ORs ranging from 1.63 to 3.72).

CONCLUSIONS

While misclassification of GUIs in our analysis is likely, our findings suggest GUIs during the periconceptional period may increase the risk for specific birth defects.

An application of data mining to identify potential risk factors for anophthalmia and microphthalmia

BACKGROUND

We examined a large number of variables to generate new hypotheses regarding a wider range of risk factors for anophthalmia/microphthalmia using data mining.

METHODS

Data were from the National Birth Defects Prevention Study, a multicentre, case-control study from 10 centres in the United States. There were 134 cases of "isolated" and 87 "nonisolated" (with other major birth defects) of anophthalmia/microphthalmia and 11 052 nonmalformed controls with delivery dates October 1997-December 2011. Using random forest, a data mining procedure, we compared the two case types with controls for 201 variables. Variables considered important ranked by random forest were included in a multivariable logistic regression model to estimate odds ratios and 95% confidence intervals.

RESULTS

Predictors for isolated cases included paternal race/ethnicity, maternal intake of certain nutrients and foods, and childhood health problems in relatives. Using regression, inverse associations were observed with greater maternal education and with increasing intake of folate and potatoes. Odds were slightly higher with greater paternal education, for increased intake of carbohydrates and beans, and if relatives had a childhood health problem. For nonisolated cases, predictors included paternal race/ethnicity, maternal intake of certain nutrients, and smoking in the home the month before conception. Odds were higher for Hispanic fathers and smoking in the home and NSAID use the month before conception.

CONCLUSIONS

Results appear to support previously hypothesised risk factors, socio-economic status, NSAID use, and inadequate folate intake, and potentially provide new areas such as passive smoking pre-pregnancy, and paternal education and ethnicity, to explore for further understanding of anophthalmia/microphthalmia.

Nongenetic risk factors for holoprosencephaly: An updated review of the epidemiologic literature

Holoprosencephaly (HPE) is a major structural birth defect of the brain that occurs in approximately 1 in 10,000 live births. Although some genetic causes of HPE are known, a substantial proportion of cases have an unknown etiology. Due to the low birth prevalence and rarity of exposure to many potential risk factors for HPE, few epidemiologic studies have had sufficient sample size to examine risk factors. A 2010 review of the literature identified several risk factors that had been consistently identified as occurring more frequently among cases of HPE, including maternal diabetes, twinning, and a predominance of females, while also identifying a number of potential risk factors that had been less widely studied. In this article, we summarize a systematic literature review conducted to update the evidence for nongenetic risk factors for HPE.

Adverse Pregnancy Outcomes among Adolescents in Northwest Russia: A Population Registry-Based Study

This study aimed to assess whether adolescents have an increased risk of adverse pregnancy outcomes (APO) compared to adult women. We used data on 43,327 births from the population-based Arkhangelsk County Birth Registry, Northwest Russia, for 2012-2014. The perinatal outcomes included stillbirth, preterm birth (<37 and <32 weeks), low and very low birthweight, 5 min Apgar score <7 and <4, perinatal infections, and the need for neonatal transfer to a higher-level hospital. Multivariable logistic regression was applied to assess the associations between age and APO. Altogether, 4.7% of deliveries occurred in adolescents. Both folic acid intake and multivitamin intake during pregnancy were more prevalent in adults. Adolescents were more likely to be underweight, to smoke, and to have infections of the kidney and the genital tract compared to adult women. Compared to adults, adolescents were at lower risk of low birthweight, a 5 min Apgar score <7, and need for neonatal transfer. Adolescents had no increased risk of other APO studied in the adjusted analysis, suggesting that a constellation of other factors, but not young age per se, is associated with APO in the study setting.

Maternal Chlamydia infection during pregnancy among younger mothers and risk of gastroschisis in singleton offspring

BACKGROUND

Prevalence of gastroschisis has been increasing in the United States (US) since 1980s. Genital infection with Chlamydia has also been increasing in prevalence, particularly among younger women. The etiology of gastroschisis is unknown. Ongoing research suggests multiple causal factors may be involved, including Chlamydia infection in mothers during pregnancy.

METHODS

Using birth certificate data from 2014 US vital records, we conducted a population-based case-control study to examine the association between prenatal Chlamydia exposure in young women (16-25 years of age) and gastroschisis in singleton offspring. Cases consisted of live births with gastroschisis, and controls had no major birth defects reported in their birth certificate. Logistic regression analysis was used to estimate crude and adjusted odds ratios (cOR and aOR) and 95% confidence intervals (CI).

RESULTS

There were 809 cases (95.6% were isolated cases) and 1,260,293 controls. Chlamydia during pregnancy was reported in 4.5% of case and 3.6% control mothers (p = .21). Case mothers were significantly more likely to be younger (16-20 years of age) at the time of delivery compared to control mothers (p < .0001). We found no significant association between Chlamydia infection during pregnancy and gastroschisis (cOR = 1.24; 95% CI = 0.89-1.73 and aOR = 1.06; 95% CI: 0.66-1.70).

CONCLUSION

With the caveat of possible misclassification of exposure and outcome variables in birth certificate data, we found no significant association between prenatal exposure to Chlamydia and gastroschisis in the offspring born to younger mothers. Future studies should refine measures by focusing on relevant risk period and biomarkers.

Maternal Chlamydia Infection During Pregnancy and Risk of Cyanotic Congenital Heart Defects in the Offspring

OBJECTIVES

Genital Chlamydia is a common bacterial sexually-transmitted infection among reproductive aged women, particularly younger populations. Cyanotic congenital heart defects (CCHDs) constitute about one quarter of all cardiac malformations at birth, and are associated with high rate of morbidity and mortality. Epidemiological research on the association between maternal Chlamydia during pregnancy and CCHDs in the offspring is lacking.

METHODS

Using data from the 2012 United States birth certificates, we examined the association between CCHDs and prenatal exposure to Chlamydia among live singleton births with CCHDs (n = 2487) and unaffected singleton births (n = 3,334,424). We estimated adjusted odds ratios (aORs) and 95% confidence intervals (CIs) using unconditional logistic regression analysis for all CCHDs combined, and isolated CCHDs (without other major congenital malformations).

RESULTS

Overall 1.7% of case and 1.7% of control women reported having Chlamydia during their pregnancies. After controlling for potential confounders, we found a weak positive association between maternal Chlamydia during pregnancy and all CCHDs combined (aOR = 1.39; 95% CI 1.02-1.90). The positive association persisted for isolated CCHD cases, but with marginal significance (aOR = 1.34; 95% CI 0.96-1.74). Subgroup analyses for younger women showed an increased risk for CCHDs; however, the associations were not statistically significant.

CONCLUSIONS

Maternal exposure to Chlamydia during pregnancy was weakly associated with a higher risk of CCHDs in the offspring. The finding should be interpreted with caution due to limitations of birth certificate data. Future studies using more robust data sources are warranted to further study the association between maternal Chlamydia during pregnancy and CCHDs in the offspring.

Trimethoprim-sulfonamide use during the first trimester of pregnancy and the risk of congenital anomalies

BACKGROUND

Sulfonamide antibacterials are widely used in pregnancy, but evidence about their safety is mixed. The objective of this study was to assess the association between first-trimester sulfonamide exposure and risk of specific congenital malformations.

METHODS

Mother-infant pairs were selected from a cohort of 1.2 million live-born deliveries (2001-2008) at 11 US health plans comprising the Medication Exposure in Pregnancy Risk Evaluation Program. Mothers with first-trimester trimethoprim-sulfonamide (TMP-SUL) exposures were randomly matched 1:1 to (i) a primary comparison group (mothers exposed to penicillins and/or cephalosporins) and (ii) a secondary comparison group (mothers with no dispensing of an antibacterial, antiprotozoal, or antimalarial medication during the same time period). The outcomes were cardiovascular abnormalities, cleft palate/lip, clubfoot, and urinary tract abnormalities.

RESULTS

We first identified 7615 infants in the TMP-SUL exposure group, of which 7595 (99%) were exposed to a combination of TMP-SUL and the remaining 1% to sulfonamides alone. After matching (1:1) to the comparator groups and only including those with complete data on covariates, there were 20 064 (n = 6688 per group) in the primary analyses. Overall, cardiovascular defects (1.52%) were the most common and cleft lip/palate (0.10%) the least common that were evaluated. Compared with penicillin/cephalosporin exposure, and no antibacterial exposure, TMP-SUL exposure was not associated with statistically significant elevated risks for cardiovascular, cleft lip/palate, clubfoot, or urinary system defects.

CONCLUSIONS

First-trimester TMP-SUL exposure was not associated with a higher risk of the congenital anomalies studied, compared with exposure to penicillins and/or cephalosporins, or no exposure to antibacterials.

Prescription of systemic antibiotics during pregnancy in primary care in Friuli Venezia Giulia, Northeastern Italy

OBJECTIVE

To investigate the prescriptions of systemic antibiotics in a population of pregnant women in Italy, to identify socio-demographic factors associated with increased risk of being prescribed potentially unsafe medications, to compare prescriptions before and during pregnancy and to identify the prescribing General Practitioners (GPs).

METHODS

A retrospective study based on administrative anonymous databases included all women resident of the Friuli Venezia Giulia Region who delivered babies in 2011 (n=9196). The antibiotic prescription risk was calculated by trimester and overall, and compared with that in the year before. Multivariate logistic regression analyses assessed the role of socio-demographic factors on the risk of being prescribed medications that should not be used as first-line.

RESULTS

6688 women (72.7%) were prescribed medicines (27363 prescriptions) during their pregnancies. Antibiotics were prescribed to 2279 women (24.8%), less commonly during pregnancy than before. Prescriptions were more frequent in the second and third trimesters. 1736 women were prescribed antibiotics other than first-line medicines (of which, seven tetracyclines and 58 quinolones, which are frankly not recommended). Those women were more frequently younger and less educated. The GPs responsible for those prescriptions were identified.

CONCLUSIONS

In order to improve the prescription of antibiotics in pregnancy, an audit with the GPs is warranted to understand their motivations, discuss clinical cases and build consensus guidelines on which antibiotics should be preferred for use in pregnancy.

Correcting for exposure misclassification using survival analysis with a time-varying exposure

PURPOSE

Survival analysis is increasingly being used in perinatal epidemiology to assess time-varying risk factors for various pregnancy outcomes. Here we show how quantitative correction for exposure misclassification can be applied to a Cox regression model with a time-varying dichotomous exposure.

METHODS

We evaluated influenza vaccination during pregnancy in relation to preterm birth among 2267 non-malformed infants whose mothers were interviewed as part of the Slone Birth Defects Study during 2006 through 2011. The hazard of preterm birth was modeled using a time-varying exposure Cox regression model with gestational age as the time-scale. The effect of exposure misclassification was then modeled using a probabilistic bias analysis that incorporated vaccination date assignment. The parameters for the bias analysis were derived from both internal and external validation data.

RESULTS

Correction for misclassification of prenatal influenza vaccination resulted in an adjusted hazard ratio (AHR) slightly higher and less precise than the conventional analysis: Bias-corrected AHR 1.04 (95% simulation interval, 0.70-1.52); conventional AHR, 1.00 (95% confidence interval, 0.71-1.41).

CONCLUSIONS

Probabilistic bias analysis allows epidemiologists to assess quantitatively the possible confounder-adjusted effect of misclassification of a time-varying exposure, in contrast with a speculative approach to understanding information bias.

Analysis of selected maternal exposures and non-syndromic atrioventricular septal defects in the National Birth Defects Prevention Study, 1997-2005

Although the descriptive epidemiology of atrioventricular septal defects (AVSDs), a group of serious congenital heart defects (CHDs), has been recently reported, non-genetic risk factors have not been consistently identified. Using data (1997-2005) from the National Birth Defects Prevention Study, an ongoing multisite population-based case-control study, the association between selected non-genetic factors and non-syndromic AVSDs was examined. Data on periconceptional exposures to such factors were collected by telephone interview from 187 mothers of AVSD case infants and 6,703 mothers of unaffected infants. Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were estimated from logistic regression models. Mothers who reported cigarette smoking during the periconceptional period were more likely to have infants with AVSDs compared with non-smokers, independent of maternal age, periconceptional alcohol consumption, infant gestational age, family history of CHDs, and study site (aOR 1.5, 95% CI 1.1-2.4). The association was strongest in mothers who smoked more than 25 cigarettes/day. In addition, mothers with periconceptional passive smoke exposure were more likely to have infants with AVSDs than unexposed mothers, independent of maternal age, active periconceptional smoking, infant gestational age, and family history of CHDs (aOR 1.4, 95% CI 1.0-2.0). No associations were observed between AVSDs and maternal history of a urinary tract infection or pelvic inflammatory disease, maternal use of a wide variety of medications, maternal occupational exposure, parental drug use, or maternal alcohol consumption. If the results of this preliminary study can be replicated, minimizing maternal active and passive smoke exposure may decrease the incidence of AVSDs.