Is the rate of congenital heart defects detected by fetal echocardiography among pregnancies conceived by in vitro fertilization really increased?: a case-historical control study

Infertility treatments and cyanotic congenital heart defects among livebirths in the USA: findings from a contemporary cohort

STUDY QUESTION

Is there an elevated risk of cyanotic congenital heart defects (CCHD) among livebirths following infertility treatments?

SUMMARY ANSWER

In this population-based study of single livebirths, infertility treatment (either ART or non-ART) was associated with a higher prevalence of CCHD among livebirths.

WHAT IS KNOWN ALREADY

The use of infertility treatment has been on the rise over the past few decades. However, there are limited studies assessing the risk of major cardiac defects following infertility treatments.

STUDY DESIGN, SIZE, DURATION

A retrospective cohort study of livebirth data from the National Vital Statistics System (NVSS) was conducted, comprising of 9.6 million singleton livebirths among first-time mothers aged 15-49 years from 2016 to 2022.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Information on infertility treatment use and CCHD was obtained from the health and medical information section of birth certificates, which was completed by healthcare staff after reviewing medical records. Logistic regression models were used to estimate odds ratios (OR) and 95% CI. Entropy balancing weighting analysis and probabilistic bias analysis were also performed.

MAIN RESULTS AND THE ROLE OF CHANCE

The proportion of births following infertility treatment increased from 1.9% (27 116) to 3.1% (43 510) during the study period. Overall, there were 5287 cases of CCHD resulting in a prevalence of 0.6 per 1000 livebirths. The prevalence was 1.2 per 1000 live births among infertility treatment users (ART: 1.1 per 1000 livebirths; non-ART: 1.3 per 1000 livebirths) while that for naturally conceived births was 0.5 per 1000 livebirths. Compared to naturally conceived births, the use of any infertility treatment (OR: 2.06, 95% CI: 1.82-2.33), either ART (OR: 2.02, 95% CI: 1.73-2.36) or other infertility treatments (OR: 2.12, 95% CI: 1.74-2.33), was associated with higher odds of CCHD after adjusting for maternal and paternal age, race and ethnicity, and education, as well as maternal nativity, marital status, source of payment, smoking status, and pre-pregnancy measures of BMI, hypertension and diabetes. This association did not differ by the type of infertility treatment (ART versus other infertility treatments) (OR: 1.04, 95% CI: 0.82-1.33, P = 0.712), and was robust to the presence of exposure and outcome misclassification bias and residual confounding.

LIMITATIONS, REASONS FOR CAUTION

The findings are only limited to livebirths. We did not have the capacity to examine termination data, but differential termination by mode of conception has not been supported by previous studies designed to consider it. Infertility treatment use was self-reported, leading to the potential for selection bias and misclassification for infertility treatment and CCHD. However, the association persisted when systematic bias as well as exposure and outcome misclassification bias were accounted for in the analyses. Information on the underlying etiology of infertility relating to either maternal, paternal, or both factors, data on specific types of ART and other infertility treatments, as well as information on subtypes of CCHD, were all not available.

WIDER IMPLICATIONS OF THE FINDINGS

In light of the increasing trend in the use of infertility treatment in the USA, and elsewhere, the finding of the current study holds significant importance for the clinical and public health of reproductive-aged individuals. The data show that the use of infertility treatment may expose offspring to elevated odds of severe congenital heart defects such as CCHD studied here. These findings cannot be interpreted causally. While our findings can assist in preconception counseling and prenatal care for pregnancies conceived by either ART or other infertility treatments, they also support some current recommendations that pregnancies resulting from infertility treatments undergo fetal echocardiography screening.

STUDY FUNDING/COMPETING INTEREST(S)

No funding was sought for the study. The authors declare that they have no conflict of interest.

TRIAL REGISTRAION NUMBER

N/A.

Assisted Reproductive Techniques and Risk of Congenital Heart Diseases in Children: a Systematic Review and Meta-analysis

Infertility is a growing phenomenon and leads to an increased use of assisted reproductive techniques (ARTs). In recent years, concerns about the safety of these procedures emerged and ARTs were hypothesized to be a risk factor for developing congenital heart diseases (CHDs) in offspring. Our aim is to investigate the association between ART and CHD, specifying results according to various subtypes of defects. We performed a systematic review and random-effects meta-analysis following the PRISMA guidelines. MEDLINE and Google Scholar were searched from January 2011 to May 2022. Data about incidence of CHD in ART were tabulated and extracted from all the studies included. Twenty-four studies were included. Pooled incidence of CHDs after IVF pregnancies was 3% (95% CI 0.3-0.4; I2 = 99%), decreasing to 1% (95% CI 0.00-0.01; I2 = 93%) for major CHDs only. An increased risk of CHDs, especially minor (i.e., not requiring surgical correction), seems to occur in ART compared with non-ART pregnancies [RR 1.71 (95% CI 1.25-2.34; I2 = 99%)]. For major CHDs, not enough evidence is available to assess the real risk. Moreover, some confounding factors (i.e., maternal age and male infertility) seem to play a critical role to determine an increased risk of CHDs. Conflicting results emerged among the studies, setting the need for further research to validate the actual evidence and state the real risk of CHD following ART pregnancies.

Cardiac problems in the fetus: a review for pediatric providers

PURPOSE OF REVIEW

The aim of this study was to provide pediatric providers with a review of the diagnosis and management of fetal cardiac disease in the current era.

RECENT FINDINGS

Prenatal detection of congenital heart disease (CHD) has improved but is still imperfect. In experienced hands, fetal echocardiography can detect severe CHD as early as the first trimester and a majority of more subtle conditions in the second and third trimesters. Beyond detection, a prenatal diagnosis allows for lesion-specific counseling for families as well as for development of a multidisciplinary perinatal management plan, which may involve in-utero treatment. Given the diversity of cardiac diagnoses and the rarity of some, collaborative multicenter fetal cardiac research has gained momentum in recent years.

SUMMARY

Accurate diagnosis of fetal cardiac disease allows for appropriate counseling, pregnancy and delivery planning, and optimization of immediate neonatal care. There is potential for improving fetal CHD detection rates. Fetal interventions are available for certain conditions, and fetal and pediatric cardiac centers have developed management plans specific to the expected postnatal physiology.

Prevalence of Congenital Heart Defects in Pregnancies Conceived by Assisted Reproductive Technology: A Cohort Study

BACKGROUND AND AIM OF THE STUDY

Pregnancies obtained by assisted reproductive technology (ART) are associated with an increased risk of complications and congenital anomalies, particularly congenital heart defects (CHDs). Therefore, our aim is to evaluate, retrospectively, the prevalence of CHD in ART pregnancies in our two centers and analyze their characteristics and outcomes.

METHODS

Observational study including fetuses conceived by ART referred between June 2011 and September 2020 and undergoing a fetal cardiac ultrasound scan. Cases with genetic, chromosomal abnormalities or extracardiac malformations were excluded. Population included 1511 pregnancies, which consisted of 269 twins and 1242 singletons, 547 IVF (in vitro fertilization), 773 ICSI (intracytoplasmic sperm injection) and 191 oocyte donations (OD).

RESULTS

CHDs were found in 29 fetuses, with an overall prevalence of 1.92% (29/1511), 1.85% (23/1242) in singletons and 2.23% in twins (6/269). Thirteen were IVF, eight ICSI and eight OD cases, with a greater risk of CHD after IVF and OD (IVF: 13/29 (44.8%)-one twin; ICSI: 8/29 (27.6%)-three twins); 22 had major and 7 minor defects. Two pregnancies with a hypoplastic left heart were terminated; the majority of live-born cases needed surgery. Three babies died (two post-surgery, one had a late death).

CONCLUSIONS

Our data show an increased prevalence of CHD after ART with a heterogeneous spectrum of diagnoses, mainly major defects.

Prevalence of Congenital Heart Defects in Pregnancies Conceived by Assisted Reproductive Technology: A Cohort Study

BACKGROUND AND AIM OF THE STUDY

Pregnancies obtained by assisted reproductive technology (ART) are associated with an increased risk of complications and congenital anomalies, particularly congenital heart defects (CHDs). Therefore, our aim is to evaluate, retrospectively, the prevalence of CHD in ART pregnancies in our two centers and analyze their characteristics and outcomes.

METHODS

Observational study including fetuses conceived by ART referred between June 2011 and September 2020 and undergoing a fetal cardiac ultrasound scan. Cases with genetic, chromosomal abnormalities or extracardiac malformations were excluded. Population included 1511 pregnancies, which consisted of 269 twins and 1242 singletons, 547 IVF (in vitro fertilization), 773 ICSI (intracytoplasmic sperm injection) and 191 oocyte donations (OD).

RESULTS

CHDs were found in 29 fetuses, with an overall prevalence of 1.92% (29/1511), 1.85% (23/1242) in singletons and 2.23% in twins (6/269). Thirteen were IVF, eight ICSI and eight OD cases, with a greater risk of CHD after IVF and OD (IVF: 13/29 (44.8%)-one twin; ICSI: 8/29 (27.6%)-three twins); 22 had major and 7 minor defects. Two pregnancies with a hypoplastic left heart were terminated; the majority of live-born cases needed surgery. Three babies died (two post-surgery, one had a late death).

CONCLUSIONS

Our data show an increased prevalence of CHD after ART with a heterogeneous spectrum of diagnoses, mainly major defects.

The association between in vitro fertilization and intracytoplasmic sperm injection treatment and the risk of congenital heart defects

OBJECTIVE

Assisted reproductive technology (ART), an effective treatment modality for infertility, is associated with a higher prevalence of congenital anomalies such as congenital heart defects (CHDs). The present study aimed to evaluate data linking CHDs in infants to pregnancies resulting from in vitro fertilization (IVF) and/or intracytoplasmic sperm injection (ICSI).

METHODS

In this study, we conducted a systematic literature search on CHDs in infants following IVF/ICSI in Google Scholar, Embase, Scopus, MEDLINE, and PubMed databases from inception to February 2020. The search strategy used combinations of search keywords that included assisted reproductive technology/ART, in vitro fertilization/IVF, intracytoplasmic sperm injection/ICSI, birth defect, congenital malformation, and congenital heart defects.

RESULTS

Fifty-six studies fulfilled the inclusion criteria and were selected in the current systematic review, which assessed the association between ART and the risk of CHDs.

CONCLUSION

Children conceived by IVF/ICSI manifested an increased risk of CHDs compared with spontaneously conceived children. Further studies are needed to assess the long-term cardiovascular safety of these techniques, which is important for the counseling of patients before the use of ART.

Utility of routine screening fetal echocardiogram in pregnancies conceived by in vitro fertilization

OBJECTIVE

To study the incidence and clinical significance of congenital heart defects (CHDs) detected by fetal echocardiography in pregnancies conceived by in vitro fertilization (IVF).

DESIGN

Cohort study comparing a prospectively maintained database of all fetal echocardiograms from 2012 to 2018 and pooled data from the Connecticut Birth Defects Registry and statewide hospital discharge data.

SETTING

Large tertiary care center.

PATIENT(S)

A total of 181,749 live births and 9,252 fetal echocardiograms were analyzed. Fetal echocardiograms in patients with a previous child with a CHD, a family history of CHD, medication exposure, diabetes, anomaly in previous pregnancy, cardiac or other abnormality noted on previous ultrasound, or monochorionic twins were excluded from the final analysis.

INTERVENTION(S)

Treatment with IVF.

MAIN OUTCOME MEASURE(S)

Incidence of CHD and odds ratios with 95% confidence intervals (CIs). Infant outcomes for cases of CHD were evaluated for clinically significant disease, defined a priori as disease requiring any medical or surgical intervention or continued follow-up with pediatric cardiology.

RESULT(S)

Fetal echocardiography was performed in 2,230 IVF pregnancies, of which 2,040 were without other known risk factors for CHD. The mean gestational age at the time of fetal echocardiography was 22.2 ± 1.4 weeks. The odds ratio for CHD in the IVF group compared with statewide population rates was 1.4 (95% CI 0.9-2.1). CHD was diagnosed in 26 fetuses, of which 21 were clinically insignificant ventricular septal defects. One fetal echocardiogram was concerning for pulmonary stenosis that was not present at birth. Four defects were clinically significant, indicating that 510 fetal echocardiograms were performed for every diagnosis of one clinically significant CHD in the IVF group.

CONCLUSION(S)

The incidence of CHD in IVF pregnancies without other risk factors is not significantly different from baseline population rates, and most CHDs diagnosed by fetal echocardiography in this group are clinically insignificant. Routine screening with fetal echocardiography in all IVF pregnancies provides limited utility beyond routine prenatal care and need not be recommended without the presence of other risk factors.

Is a Fetal Echocardiography Necessary in IVF-ICSI Pregnancies After Anatomic Survey?

PURPOSE

In vitro fertilization with intracytoplasmic sperm injection (IVF-ICSI) is generally regarded as an indication for fetal echocardiography due to a reported increased risk of congenital abnormalities including cardiac anomalies. In this study we evaluated the utility of fetal echocardiography after anatomic survey in an experienced center.

METHODS

This was a retrospective case review of in vitro fertilization with intracytoplasmic sperm injection pregnancies who had echocardiography in our institution from January 1996 to October 2010.

RESULTS

Records from 85 mothers and 110 fetuses were identified. During anatomic survey, six cardiac anomalies were identified, including four ventricular septal defects, one pulmonary-aortic disproportion, and one post-valvular pulmonary artery dilatation. At fetal echocardiography, two of the four ventricular septal defects were confirmed and an additional three were identified. The most common cardiac anomaly seen in our population of IVF-ICSI pregnancies was ventricular septal defect, which was identified in 3.6% of all cases in the neonatal period. Of ventricular septal defects identified in the prenatal period, 71% resolved before birth.

CONCLUSION

In experienced centers, a fetal echocardiography may not be necessary if the 3 vessels tracheal view of the heart is evaluated and the heart is evaluated carefully for a ventricular septal defect.

Associations of Assisted Reproductive Technology and Twin Pregnancy With Risk of Congenital Heart Defects

IMPORTANCE

The extent to which assisted reproductive technology is associated with increased risk of congenital heart defects independent of its known association with twinning remains uncertain.

OBJECTIVE

To assess the extent to which assisted pregnancy is associated with increased risk of congenital heart defects independent of its known association with twinning.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study linked records of congenital heart defect diagnoses with assisted reproductive technology cycles in 507 390 singleton or twin pregnancies (10 149 assisted pregnancies and 497 241 nonassisted pregnancies), including singleton and twin early pregnancy losses, stillbirths, and live births (follow-up to 1 year of age) in Ontario, Canada, between April 1, 2012, and October 31, 2015. Statistical analysis was performed from January 1, 2017, to September 9, 2019.

EXPOSURES

Assisted reproductive technology and its 2 subtypes: intracytoplasmic sperm injection and in vitro fertilization without intracytoplasmic sperm injection.

MAIN OUTCOMES AND MEASURES

The main outcome was congenital heart defects (prevalence and relative risk measured as odds ratios [ORs]). Mediation analysis was performed to assess the extent to which the association between assisted reproductive technology and congenital heart defects was mediated by twinning.

RESULTS

Of 507 390 mother-infant pairs with singleton or twin pregnancies evaluated, the prevalence of congenital heart defects in assisted pregnancies (223 [2.2%]) was higher than that in nonassisted pregnancies (6057 [1.2%]; crude OR, 1.82; 95% CI, 1.59-2.09). The strength of the association between assisted pregnancy and congenital heart defects decreased after adjusting for several risk factors simultaneously (adjusted OR, 1.70; 95% CI, 1.48-1.95). Further mediation analysis indicated that most of the association between assisted pregnancy and congenital heart defects was mediated by twinning (adjusted OR, 1.68; 95% CI, 1.44-1.92), and the natural direct association of assisted pregnancy with congenital heart defects among singleton pregnancies was 1.09 (95% CI, 0.93-1.25). Mediation of twinning accounted for 87.3% of the association.

CONCLUSIONS AND RELEVANCE

Our study results suggest that the association between assisted reproductive technology and congenital heart defects may be mediated by twinning.

Congenital heart defects in IVF/ICSI pregnancy: systematic review and meta-analysis

OBJECTIVE

There is no consensus in current practice guidelines on whether conception by in-vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) techniques is an indication for performing a fetal echocardiogram. The aim of the study was to assess whether congenital heart defects (CHD) occur more often in pregnancies conceived after IVF/ICSI as compared with those conceived spontaneously.

METHODS

A systematic search for studies was conducted of PubMed/MEDLINE, EMBASE and Scopus from inception to September 2017. The search included the following medical subject heading (MeSH) terms alone or in different combinations: 'IVF', 'IVF/ICSI', 'ART pregnancy', 'assisted conception', 'birth defect', 'congenital heart defects' and 'congenital malformation or abnormalities'. Studies comparing neonatal incidence of CHD in pregnancies conceived after IVF/ICSI and those conceived spontaneously were included. Studies reporting on other types of assisted reproductive technology (ART) or lacking information concerning termination of pregnancy were excluded. Chromosomal abnormalities were excluded in all analyzed studies. A meta-analysis of selected cohort studies was conducted to estimate the pooled odds ratio (OR) with 95% CI using a random-effects model. Statistical heterogeneity among the studies was evaluated with the I² statistic and Q-test.

RESULTS

Forty-one studies were identified for review including six case-control and 35 cohort studies. Data of eight selected cohort studies were used for meta-analysis. A total of 25 856 children conceived from IVF/ICSI techniques and 287 995 children conceived spontaneously, involving both singleton and multiple gestations, were included in the analysis. Total CHD events were 337/25 856 (1.30%) and 1952/287 995 (0.68%) in the IVF/ICSI and spontaneous conception groups, respectively. The risk of CHD was significantly increased in the IVF/ICSI group as compared with the spontaneous conception group (pooled OR, 1.45; 95% CI, 1.20-1.76; P = 0.0001; I²  = 44%; P = 0.08). In the subgroup of singleton IVF pregnancies, a significant difference was also obtained (OR, 1.55; 95% CI, 1.21-1.99; P = 0.0005; I²  = 36%; P = 0.18) and also multiple confounding factors adjusted ORs showed statistical significance (pooled OR, 1.29; 95% CI, 1.03-1.60; P = 0.02; I²  = 0%; P = 0.43).

CONCLUSION

Fetuses conceived with IVF/ICSI methods are at an increased risk of developing CHD compared with those conceived spontaneously. However, this finding deserves further investigation due to heterogeneity of both ART procedures and cardiac defects. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

[NKX2.5 and TBX5 gene mutations in in vitro fertilization children with congenital heart disease]

OBJECTIVE

To explore the differences of NKX2.5 and TBX5 gene mutations between in vitro fertilization (IVF) children with congenital heart disease (CHD) and naturally conceived children with CHD.

METHODS

Blood samples from 68 IVF children with CHD and 98 naturally conceived children with CHD were collected. The mutations in coding regions 1 and 2 of the NKX2.5 gene, and coding regions 4, 5, and 8 of the TBX5 gene were examined by polymerase chain reaction (PCR) and DNA sequencing.

RESULTS

An A-to-G mutation at nucleotide 63 (c.63A>G) in coding region 1 of the NKX2.5 gene was found in both IVF and naturally conceived children with CHD. There were no significant differences in genotype and allele frequencies at c.63A>G locus of the NKX2.5 gene between the two groups. No mutations were detected in coding region 2 of the NKX2.5 gene and coding regions 4, 5 and 8 of the TBX5 gene.

CONCLUSIONS

There is no difference in NKX2.5 and TBX5 gene mutations between IVF and naturally conceived children with CHD. Therefore, it is presumed that assisted reproductive technology may not lead to mutations in the NKX2.5 and TBX5 genes.

Congenital heart disease in twins: The contribution of type of conception and chorionicity

BACKGROUND

Increased incidence of congenital heart disease (CHD) has been reported in the offspring of monochorionic twin gestations. Assisted reproductive technology (ART), which is related to increased rates of twinning, has also been associated with higher risk of birth defects. We studied the incidence of CHD in a cohort of twins to clarify the contribution of type of conception and chorionicity.

METHODS

Data concerning 874 live-born twins of which at least one was admitted in our Neonatal Unit during 1995-2012 were analysed. Forty-five % (N=197) of the gestations resulted from ART (in vitro fertilisation or intracytoplasmic sperm insertion).

RESULTS

In the ART group 32/389 (8.2%) had CHD compared to 21/485 (4.3%) infants conceived naturally (OR 1.90, 95%CI 1.08-3.34, p=0.024). Spontaneous-conception gestations had higher incidence of monochorionic placentation (47/245 versus 4/197, p<0.001), and included younger mothers (29.1±5.2 versus 33.9±5.5years, p<0.001) who had higher parity (median 2 [range 1-7] versus 1 Pinborg (2005), Blondel and Kaminski (2002), Knopman et al. (2014), Kyvik and Derom (2006) ; p<0.001). Multivariable logistic regression analysis showed that ART (OR 2.60, 95% CI 1.24-5.45) and monochorionicity (OR 3.49, 95% CI 1.57-7.77) were significant determinants of CHD, independently of maternal age, parity, and the gender of the offspring.

CONCLUSIONS

We confirmed that monochorionic twins have increased risk of CHD and we documented a higher incidence of CHD in ART twins independently of chorionicity. We suggest improvement of echocardiographic skills of health care professionals involved in prenatal screening and foetal cardiology referral of ART dichorionic twins with suspicious findings at screening, in addition to all monochorionic gestations.

Diagnosis and treatment of fetal cardiac disease: a scientific statement from the American Heart Association

BACKGROUND

The goal of this statement is to review available literature and to put forth a scientific statement on the current practice of fetal cardiac medicine, including the diagnosis and management of fetal cardiovascular disease.

METHODS AND RESULTS

A writing group appointed by the American Heart Association reviewed the available literature pertaining to topics relevant to fetal cardiac medicine, including the diagnosis of congenital heart disease and arrhythmias, assessment of cardiac function and the cardiovascular system, and available treatment options. The American College of Cardiology/American Heart Association classification of recommendations and level of evidence for practice guidelines were applied to the current practice of fetal cardiac medicine. Recommendations relating to the specifics of fetal diagnosis, including the timing of referral for study, indications for referral, and experience suggested for performance and interpretation of studies, are presented. The components of a fetal echocardiogram are described in detail, including descriptions of the assessment of cardiac anatomy, cardiac function, and rhythm. Complementary modalities for fetal cardiac assessment are reviewed, including the use of advanced ultrasound techniques, fetal magnetic resonance imaging, and fetal magnetocardiography and electrocardiography for rhythm assessment. Models for parental counseling and a discussion of parental stress and depression assessments are reviewed. Available fetal therapies, including medical management for arrhythmias or heart failure and closed or open intervention for diseases affecting the cardiovascular system such as twin-twin transfusion syndrome, lung masses, and vascular tumors, are highlighted. Catheter-based intervention strategies to prevent the progression of disease in utero are also discussed. Recommendations for delivery planning strategies for fetuses with congenital heart disease including models based on classification of disease severity and delivery room treatment will be highlighted. Outcome assessment is reviewed to show the benefit of prenatal diagnosis and management as they affect outcome for babies with congenital heart disease.

CONCLUSIONS

Fetal cardiac medicine has evolved considerably over the past 2 decades, predominantly in response to advances in imaging technology and innovations in therapies. The diagnosis of cardiac disease in the fetus is mostly made with ultrasound; however, new technologies, including 3- and 4-dimensional echocardiography, magnetic resonance imaging, and fetal electrocardiography and magnetocardiography, are available. Medical and interventional treatments for select diseases and strategies for delivery room care enable stabilization of high-risk fetuses and contribute to improved outcomes. This statement highlights what is currently known and recommended on the basis of evidence and experience in the rapidly advancing and highly specialized field of fetal cardiac care.

Ultrasound in twins: dichorionic and monochorionic

The objective of this review is to assess the evidence that supports the use of ultrasound in twin pregnancies. Although many of the indications for obstetric ultrasound are the same in both singleton and multiple gestations, there are special considerations as well as unique conditions in twins that require additional imaging studies. The reasons for ultrasound in twins include pregnancy dating, determination of chorionicity, nuchal translucency assessment, anatomical survey, placental evaluation, cervical length assessment, routine fetal growth, and serial surveillance of pregnancies complicated by anomalies, cervical shortening, fetal growth disturbances, and amniotic fluid abnormalities. Twins with monochorionic placentation require heightened scrutiny for monoamnionicity, conjoined twins, twin reversed arterial perfusion (TRAP) syndrome, twin-twin transfusion syndrome, unequal placental sharing with discordant twin growth or selective intrauterine fetal growth restriction (IUGR), twin anemia-polycythemia sequence (TAPS), and single fetal demise. Ultrasound is essential for the detection and management of conditions that can complicate dichorionic and monochorionic twin pregnancies.

Maternal and paternal environmental risk factors, metabolizing GSTM1 and GSTT1 polymorphisms, and congenital heart disease

Congenital heart defects (CHDs) are the most prevalent of all birth malformations arising from the complex interplay of environmental exposures and genes. Modifiable environmental risk factors are still largely unknown, especially for paternal exposure. The aim of the present study was to examine the association between the environmental exposures of both parents and CHD risk and to explore the modification effect of metabolizing gene polymorphisms in children who lack the genetic capacity to produce the glutathione S-transferase (GST) GSTM1 and GSTT1 enzymes. A total of 330 parents of a child with CHD and 330 parents of a child without any congenital malformations were compared in terms of lifestyle habits and toxicant exposure. GST gene polymorphisms were investigated in 180 patients with CHD (104 males, age 4.9 ± 5.8 years). Paternal smoking (≥15 cigarettes/day) was significantly associated with CHD risk (odds ratio [OR] 2.1, 95% confidence interval [CI] 1.3 to 3.5, p = 0.002). Both maternal (OR 2.6, 95% CI 1.6 to 4.2, p <0.0001) and paternal (OR 2.5, 95% CI 1.6 to 3.8, p <0.0001) occupational/environmental exposures increased the risk of CHD. Also, a significant additive risk (OR 4.5, 95% CI 2.5 to 8.3, p <0.0001) was found when both parents were exposed to toxicants. Both maternal (OR 3.6, 95% CI 1.1 to 11.2, p = 0.03) and paternal (OR 3.3, 95% CI 1.0 to 10.8, p = 0.03) exposure to toxicants increased the CHD risk in children who carried the combined null GST genotypes. The effect for the combined null GST genotypes was also stronger (OR 6.5, 95% CI 1.5 to 28.0) when both parents were exposed. In conclusion, paternal smoking and exposure to toxicants for both parents affect the risk of children with CHD. Polymorphisms in GST genes can modify a person's risk of toxicant exposure-induced disease.