Maternal smoking during pregnancy and the risk of congenital urogenital malformations: A systematic review and meta-analysis

Maternal and fetal risk factors for congenital anomalies of the kidney and urinary tract: a birth cohort study in urban China

BACKGROUND

Congenital anomalies of the kidney and urinary tract (CAKUT) are among the most common causes of kidney diseases in children. Previous studies on CAKUT etiologies have been predominantly focused on non-modifiable genetic risk factors. The existing nongenetic studies are limited by lack of comprehensive investigation of potentially modifiable risk factors and the inability to distinguish among various phenotypes of CAKUT. Therefore, this study aimed to comprehensively evaluate both maternal and fetal risk factors of CAKUT, sorted by disease phenotype.

METHODS

A prospective birth cohort study was conducted among 10,179 women who delivered a singleton live newborn in Lanzhou, China, between 2010 and 2012. Face-to-face interviews were conducted among the participants within 1-3 days after delivery using standard questionnaires to collect information on maternal demographics and characteristics. All newborns underwent postnatal renal ultrasonographic screening during their routine 1-month checkup. Clinical data, including birth outcomes and maternal complications, were confirmed by reviewing their medical records. Maternal and fetal risk factors were compared in children with and without CAKUT. Multivariable logistic regression analysis was performed to identify independent risk factors of CAKUT and their phenotypes, respectively.

RESULTS

A total of 489 (4.8%) cases of CAKUT were identified. Logistic regression revealed that maternal overweight (pre-pregnancy), gestational diabetes, preterm birth, and low birth weight were independent risk factors for CAKUT. Maternal overweight increased the risk of vesicoureteral reflux (VUR, odds ratio (OR) = 1.441, 95% confidence interval (CI) 1.010-2.057) and posterior urethral valves (PUV, OR = 1.868, 95% CI 1.074-3.249). Gestational diabetes increased the risk of ureteropelvic junction obstruction (UPJO, OR = 1.269; 95% CI 1.044-1.543) and posterior urethral valves (OR = 1.794; 95% CI 1.302-2.474). Preterm birth increased the risk of ureteropelvic junction obstruction (OR = 1.056; 95% CI 1.004-1.111).

CONCLUSIONS

Our study identified various risk factors associated with different CAKUT phenotypes, stressing the importance of separate analyses for each phenotype. Our findings may provide helpful guidance on developing targeted and effective CAKUT prevention programs in the future.

The Impact of Maternal Passive Tobacco Smoke on Neonatal Myocardiopathy in Mice

BACKGROUND

Tobacco smoke has a global impact, particularly on pregnant women and their newborns. An emerging body of research suggests that passive tobacco smoking is a significant contributor to congenital cardiovascular disorders (CVDs).

AIM OF THE STUDY

This study aimed to mimic the effects of passive tobacco smoke (PTS) on neonates exposed throughout the gestational period.

METHODS

Female mice (DPC = 0) were exposed to PTS; 24 cigarettes/day with an interval of 10 min between each cigarette in a specialized smoke chamber from conception to birth. Histopathological analysis was employed to evaluate PTS-induced cardiac damage in neonates.

RESULTS

The results revealed significant alterations in cell structure, namely, widened interstitial spaces, hemorrhage, pyknotic nuclei, inflammatory cell infiltration, collagen deposition, and fibrosis.

CONCLUSION

Maternal exposure to PTS during pregnancy may lead to neonatal myocardiopathy.

High Prevalence of Tobacco Consumption among Pregnant Women in a Southern European City (Seville): A Challenge for the Health System

The prevalence of prenatal tobacco exposure remains high in many countries, particularly in southern Europe. The aims of this study were to estimate the prevalence of smoking among pregnant women in a southern Spanish city (Seville) and to identify the associated sociodemographic and obstetric characteristics. In a descriptive, cross-sectional study, a random sample of pregnant women who were scheduled to undergo a morphology scan at their public referral hospital in their 20th week of gestation were interviewed in person. At the start of pregnancy, 38.2% of the pregnant women were smokers. In the twentieth week, 19.1% continued to smoke, and the same percentage had quit. The prevalence of smoking in pregnant women was higher among those with a low level of education (60% among pregnant women with no studies and 30.4% in those with primary education) and among those who had had abortions (38.5%). Pregnant smokers with obesity were the least likely to have given up smoking during pregnancy. Women with a lower educational level should be a prime target for cross-sectoral interventions aimed at preventing prenatal tobacco exposure. Implementation of support measures for providing effective clinical advice in preconception and prenatal care regarding healthy lifestyles is particularly needed.

Early-life exposures and long-term health: adverse gestational environments and the programming of offspring renal and vascular disease

According to the Developmental Origins of Health and Disease hypothesis, exposure to certain environmental influences during early life may be a key determinant of fetal development and short- and long-term offspring health. Indeed, adverse conditions encountered during the fetal, perinatal, and early childhood stages can alter normal development and growth, as well as put the offspring at elevated risk of developing long-term health conditions in adulthood, including chronic kidney disease and cardiovascular diseases. Of relevance in understanding the mechanistic basis of these long-term health conditions are previous findings showing low glomerular number in human intrauterine growth restriction and low birth weight-indicators of a suboptimal intrauterine environment. In different animal models, the main suboptimal intrauterine conditions studied relate to maternal dietary manipulations, poor micronutrient intake, prenatal ethanol exposure, maternal diabetes, glucocorticoid and chemical exposure, hypoxia, and placental insufficiency. These studies have demonstrated changes in kidney structure, glomerular endowment, and expression of key genes and signaling pathways controlling endocrine, excretion, and filtration function of the offspring. This review aims to summarize those studies to uncover the effects and mechanisms by which adverse gestational environments impact offspring renal and vascular health in adulthood. This is important for identifying agents and interventions that can prevent and mitigate the long-term consequences of an adverse intrauterine environment on the subsequent generation.NEW & NOTEWORTHY Human data and experimental animal data show that suboptimal environments during fetal development increase the risk of renal and vascular diseases in adult-life. This is related to permanent changes in kidney structure, function, and expression of genes and signaling pathways controlling filtration, excretion, and endocrine function. Uncovering the mechanisms by which offspring renal development and function is impacted is important for identifying ways to mitigate the development of diseases that strain health care services worldwide.

Does Exposure to Ambient Air Pollution Affect Gestational Age and Newborn Weight?-A Systematic Review

Current evidence suggests that airborne pollutants have a detrimental effect on fetal growth through the emergence of small for gestational age (SGA) or term low birth weight (TLBW). The study's objective was to critically evaluate the available literature on the association between environmental pollution and the incidence of SGA or TLBW occurrence. A comprehensive literature search was conducted across Pubmed/MEDLINE, Web of Science, Cochrane Library, EMBASE, and Google Scholar using predefined inclusion and exclusion criteria. The methodology adhered to the PRISMA guidelines. The systematic review protocol was registered in PROSPERO with ID number: CRD42022329624. As a result, 69 selected papers described the influence of environmental pollutants on SGA and TLBW occurrence with an Odds Ratios (ORs) of 1.138 for particulate matter ≤ 10 μm (PM10), 1.338 for particulate matter ≤ 2.5 μm (PM2.5), 1.173 for ozone (O3), 1.287 for sulfur dioxide (SO2), and 1.226 for carbon monoxide (CO). All eight studies analyzed validated that exposure to volatile organic compounds (VOCs) is a risk factor for SGA or TLBW. Pregnant women in the high-risk group of SGA occurrence, i.e., those living in urban areas or close to sources of pollution, are at an increased risk of complications. Understanding the exact exposure time of pregnant women could help improve prenatal care and timely intervention for fetuses with SGA. Nevertheless, the pervasive air pollution underscored in our findings suggests a pressing need for adaptive measures in everyday life to mitigate worldwide environmental pollution.

The epidemiology of cryptorchidism and potential risk factors, including endocrine disrupting chemicals

Congenital cryptorchidism, also known as undescended testis, is the condition where one or both testes are not in place in the scrotum at birth and is one of the most common birth defects in boys. Temporal trends and geographic variation in the prevalence of cryptorchidism from 1% to 9% have been reported in prospective cohort studies. The testes develop in the abdominal cavity and descend to the scrotum in two phases, which should be completed by gestational week 35. Thus, the risk of cryptorchidism is higher in preterm boys. In many cases a spontaneous descent occurs during the first months of life during the surge of gonadotropins and testosterone. If not, the testis is usually brought down to the scrotum, typically by surgery, to increase future fertility chances and facilitate cancer surveillance. The increasing frequency of impaired semen quality and testicular cancer, with which cryptorchidism is associated, represents a concern for male reproductive health in general and a need to understand its risk factors. The risk of cryptorchidism is closely related to gestational factors (preterm birth, low birth weight and intrauterine growth restriction), and especially maternal smoking seems to be a risk factor. Evidence is accumulating that the increasing prevalence of cryptorchidism is also related to prenatal exposure to environmental chemicals, including endocrine disrupting compounds. This association has been corroborated in rodents and supported by ecological studies. Conducting human studies to assess the effect of endocrine disrupting chemicals and their interactions is, however, challenged by the widespread concomitant exposure of all humans to a wide range of chemicals, the combined effect of which and their interactions are highly complex.

Predictive factors and adverse perinatal outcomes associated with maternal smoking status

To identify risk factors for smoking among pregnant women, and adverse perinatal outcomes among pregnant women. A case-control study of singleton full-term pregnant women who gave birth at a university hospital in Jordan in June 2020. Pregnant women were divided into three groups according to their smoking status, active, passive, and non-smokers. They were interviewed using a semi-structured questionnaire that included demographic data, current pregnancy history, and neonatal outcomes. Low-level maternal education, unemployment, secondary antenatal care, and having a smoking husband were identified as risk factors for smoke exposure among pregnant women. The risk for cesarean section was ninefold higher in nulliparous smoking women. Women with low family income, those who did not receive information about the hazards of smoking, unemployed passive smoking women, and multiparty raised the risk of neonatal intensive care unit admission among active smoking women. This risk increased in active and passive women with lower levels of education, and inactive smoking women with low family income by 25 times compared to women with a higher level of education. Smoking is associated with adverse perinatal outcomes. Appropriate preventive strategies should address modifiable risk factors for smoking during pregnancy.

Cotinine concentrations in maternal serum and amniotic fluid during pregnancy and risk of testicular germ cell cancer in the offspring: A prospective nested case-control study

Maternal smoking in pregnancy may increase the risk of testicular germ cell cancer (TGCC) in offspring, but current evidence remains inconclusive. We performed a nested case-control study using cotinine measurements in maternal serum and amniotic fluid as a biomarker for tobacco exposure during pregnancy. A total of 654 males with maternal serum (n = 359, ncases/controls  = 71/288) and/or amniotic fluid (n = 295, ncases/controls  = 66/229) samples were included. Data on TGCC diagnoses and relevant covariates were derived from nationwide Danish health registries. Cotinine was quantified by liquid chromatography tandem mass spectrometry. An adapted cox regression model estimated the risk of TGCC considering active and inactive tobacco use defined according to cotinine concentrations of <, ≥15 ng/ml. Overall, the concentrations of cotinine were comparable in maternal serum and amniotic fluid (medianserum/amniotic fluid : 2.1/2.6 ng/ml). A strong statistically significant correlation was detected in 14 paired samples (Spearman rho: 0.85). Based on maternal serum cotinine concentrations, exposure to active tobacco use was not associated with risk of TGCC in offspring (HR 0.88, 95% CI 0.51; 1.52). Similarly, based on amniotic fluid cotinine concentrations, exposure to active tobacco use was not associated with risk of TGCC (HR 1.11, 95% CI 0.64; 1.95). However, different risks were observed for seminomas and nonseminomas in both matrices, but none were statistically significant. Our findings did not provide convincing evidence supporting that exposure to tobacco during pregnancy is associated with TGCC.

Environmental and parental risk factors for congenital solitary functioning kidney - a case-control study

BACKGROUND

The etiology of congenital solitary functioning kidney (CSFK) is largely unknown but likely includes various risk factors. We performed a case-control study to compare exposure to environmental and parental risk factors during embryonic kidney development between children with CSFK and healthy controls.

METHODS

We included 434 children with CSFK and 1302 healthy controls from the AGORA data- and biobank matched on year of birth. Exposure to potential risk factors was investigated using parental questionnaire data. Crude and adjusted odds ratios (aORs) with 95% confidence intervals (CIs) were estimated for each potential risk factor. Multiple imputation was used to deal with missing values. Confounders for each potential risk factor were selected using directed acyclic graphs.

RESULTS

Maternal stress was newly identified as a risk factor for CSFK (aOR 2.1, 95% CI 1.2-3.5). Known associations with conception using in vitro fertilization/intracytoplasmic sperm injection (aOR 1.8, 95% CI 1.0-3.2), maternal infections during pregnancy (aOR 2.5, 95% CI 1.4-4.7), smoking during pregnancy (aOR 1.4, 95% CI 1.0-2.0), and parental CAKUT (aOR 6.6, 95% CI 2.9-15.1) were confirmed, but previous associations with diabetes and obesity could not be replicated. Folic acid supplement use and younger maternal age seemed to reduce the risk of CSFK (aORs 0.7, 95% CI 0.5-1.0, and 0.8, 95% CI 0.6-1.0, respectively).

CONCLUSIONS

Environmental and parental risk factors are likely to be involved in the development of CSFK and future studies should combine genetic, environmental, and gene-environment interaction analyses. Women wanting to become pregnant should consider optimizing their health and lifestyle. A higher-resolution version of the Graphical abstract is available as Supplementary information.

Maternal Exposure to Cigarette Smoke during Pregnancy and Testicular Cancer in Offspring: A Systematic Review and Meta-Analysis

Background: Maternal exposure to cigarette smoke in pregnancy may play a role in the development of testicular cancer in offspring. An updated and comprehensive systematic review of the available evidence is needed. Objective: To identify and evaluate current evidence on maternal exposure to cigarette smoke during pregnancy and testicular cancer in offspring. Methods: A systematic search of English peer-reviewed original literature in PubMed through a block search approach. Publications were considered if assessing maternal exposure to cigarette smoke and the risk of testicular cancer in offspring. Results: Among the 636 identified records, 14 publications were eligible for review and 10 for meta-analysis. Quality assessment of the publications was conducted. Most included publications were case-control studies (n = 11, 79%), while the remaining were ecological studies (n = 3, 21%). Completeness of reporting was high, but more than half were considered subject to potential bias. The trend synthesis showed that half (n = 7) of the included publications demonstrated a higher risk of testicular cancer in the sons of mothers exposed to cigarette smoke during pregnancy. The meta-analysis generated an overall summary risk estimate of 1.00 (95% CI: 0.88; 1.15) (n = 10 publications), with a lower risk for seminoma (0.79, 95% CI: 0.59; 1.04) and nonseminoma (0.96, 95% CI: 0.74; 1.26) (n = 4 publications). Conclusions: This systematic review did not provide evidence of an association between maternal exposure to cigarette smoke and risk of testicular cancer in offspring. An overall positive trend was suggested, but it had low statistical precision. The methodological limitations across publications encourage further research based on valid exposure data.

Parental smoking and risk of hypospadias: An updated meta-analysis of observational studies

Background

Inconsistent relationships have been shown between cigarette smoking and hypospadias in offspring. The purpose of this study was to summarize epidemiological evidence to evaluate the relationship between parental smoking and the risk of hypospadias.

Methods

Up until October 2022, PubMed, EMBASE, Web of Science, and the Cochrane Library were systematically searched for qualified research. The summary RRs and 95% CIs were calculated using either a fixed-effects or a random-effects model. There were subgroup analyses undertaken to identify potential sources of heterogeneity.

Results

44 studies with 16,637,830 participants were included in our meta-analysis. Overall, maternal active smoking [risk ratio (RR) = 0.94; 95% confidence interval (CI): 0.90-0.99; P < 0.01] was significantly associated with the risk of hypospadias. And neither paternal smoking (RR = 1.00; 95% CI: 0.86-1.15) nor maternal passive smoking (RR = 0.91; 95% CI: 0.60-1.23) was associated with the risk of hypospadias.

Conclusion

Our study discovered an association between maternal active smoking and a decreased risk of hypospadias, which may be due to the effect of smoking on androgen. However, as numerous studies have proved that cigarette smoking during pregnancy increases the risk of overall birth abnormalities in offspring, quitting cigarettes before pregnancy positively influences the health of offspring and should be advocated worldwide.

Systematic review registration

[www.crd.york.ac.uk/prospero], identifier [CRD42022319378].