Association of twinning and maternal age with major structural birth defects in Utah, 1999 to 2008

Very young and advanced maternal age strongly elevates the occurrence of nonchromosomal congenital anomalies: a systematic review and meta-analysis of population-based studies

BACKGROUND

Nonchromosomal congenital anomalies (NCAs) are the most common cause of infant mortality and morbidity. The role of maternal age is well known, although the specifics are not thoroughly elucidated in the literature.

OBJECTIVE

To evaluate the role of maternal age in the incidence of NCAs and to pinpoint age groups at higher risk to refine screening protocols.

STUDY DESIGN

A systematic review and meta-analysis were conducted following the PRISMA 2020 guidelines and Cochrane Handbook. Searches were performed on October 19, 2021, across MEDLINE (via PubMed), Cochrane Library (CENTRAL), and Embase. Population-based studies assessing the impact of maternal age on the incidence of NCAs in pregnant women were included, without restrictions on age range, country, or comorbidities. A random-effects model was used for pooling effect sizes, considering the heterogeneity across studies.

RESULTS

From 15,547 studies, 72 were synthesized. Maternal age >35 showed an increased NCA risk (risk ratio [RR]: 1.31, confidence interval [CI]: 1.07 -1.61), rising notably after>40 (RR: 1.44, CI: 1.25 -1.66). The latter changes to 1.25 (CI: 1.08 -1.46) if the co-occurrence of chromosomal aberrations is excluded. Specific anomalies like cleft lip/palate (>40, RR: 1.57, CI: 1.11 -2.20) and circulatory system defects (>40, RR: 1.94, CI: 1.28 -2.93) were significantly associated with advanced maternal age. Conversely, gastroschisis was linked to mothers <20 (RR: 3.08, CI: 2.74 -3.47).

CONCLUSION

The study confirms that both very young and advanced maternal ages significantly increase the risk of NCAs. There is a pressing need for age-specific prenatal screening protocols to better detect these anomalies, especially considering the current trend of delayed childbearing. Further research is required to fully understand the impact of maternal age on the prevalence of rarer NCAs.

Neonatal and Early Childhood Outcomes of Twin and Singleton Infants Born Preterm

OBJECTIVE

To compare neonatal and early-childhood outcomes of twins and singletons born preterm and explore the association of chorionicity with outcomes.

STUDY DESIGN

This was a national retrospective cohort study of singleton and twin infants admitted at 230/7-286/7 weeks to level III neonatal intensive care units in Canada (2010-2020). The primary neonatal outcome was a composite of neonatal death or severe neonatal morbidities. The primary early-childhood outcome was a composite of death or significant neurodevelopmental impairment.

RESULTS

The study cohort included 3554 twin and 12 815 singleton infants. Twin infants born at 230/7-256/7 weeks had a greater risk of the composite neonatal outcome (adjusted risk ratio 1.04, 95% CI 1.01-1.07). However, these differences were limited to the subgroups of same-sex and monochorionic twin pregnancies. Twin infants of 230/7-256/7 weeks were also at an increased risk of the composite early-childhood outcome (adjusted risk ratio 1.22, 95% CI 1.09-1.37). Twin infants of 260/7-286/7 weeks were not at an increased risk of adverse neonatal outcomes or the composite early-childhood outcome compared with singleton infants.

CONCLUSIONS

Among infants born at 230/7-256/7 weeks, twins have a greater risk of adverse neonatal outcomes and the composite early-childhood outcome than singleton infants. However, the increased risk of adverse neonatal outcomes is mostly limited to monochorionic twins and may thus be driven by complications related to monochorionic placentation.

Global Epidemiology of Craniosynostosis: A Systematic Review and Meta-Analysis

OBJECTIVE

Craniosynostosis leads to craniofacial deformity and may result in raised intracranial pressure, neurocognitive deficits, and psychosocial issues if left untreated. The global epidemiology of craniosynostosis is unknown. We conducted a meta-analysis to estimate global birth prevalence.

METHODS

PubMed, Embase, and Scopus were searched. Articles were screened by title and abstract and then full text. Meta-analysis of birth prevalence was conducted. Birth prevalence figures were combined with metrics detailing the number of births in 2019 to estimate the number of children worldwide born with craniosynostosis annually.

RESULTS

Of 1378 resultant articles, 24 studies were included, including 20 providing data for craniosynostosis overall and 9 for nonsyndromic craniosynostosis. World Health Organization regions of included studies were 9 (37.5%) European Region, 8 (33.3%) Region of the Americas, 4 (16.7%) Western Pacific region, 2 (8.3%) African Region, and 1 (4.2%) Eastern Mediterranean Region. Lower middle-income countries represented only 4% of study manuscripts. The overall birth prevalence of craniosynostosis was 5.9 per 10,000 live births (20 studies; 95% confidence interval [CI]: 3.9, 8.4; I² = 100%). The birth prevalence of nonsyndromic craniosynostosis was 5.2 per 10,000 live births (9 studies; 95% CI: 3.4, 7.3; I² = 98%). The number of children born globally with craniosynostosis in 2019 was estimated to be 84,665 (95% CI: 55,965, 120,540), including 72,857 (95% CI: 47,637, 120,280) with nonsyndromic craniosynostosis.

CONCLUSIONS

Craniosynostosis is a common condition that affects the neurocognitive and craniofacial skeletal development of children worldwide. Initiatives to scale up capacity for craniosynostosis epidemiologic research and clinical care are warranted, particularly in low- and middle-income countries.

Crown-Rump Length Discordance, Increased Nuchal Translucency, and Detection of Fetal Structural Anomalies in Twin Pregnancies in the First Trimester: 5 Years of Experience in a Tertiary Hospital in China

OBJECTIVE

To evaluate the efficacy of the first-trimester ultrasound scan in the detection of fetal structural anomalies in twin pregnancies. To examine the association between increased nuchal translucency (NT) thickness, crown-rump length (CRL) or NT discordance, and detection of structural anomalies in a large twin series in China.

METHODS

We performed retrospective analysis of twin pregnancies who underwent 11-13⁺⁶ -week and second-trimester anomaly scan and booked at Beijing Obstetrics and Gynecology Hospital between January 2012 and December 2016. Measurement of fetal CRL/NT and assessment of fetal anatomic structures were based on standard (not detailed) protocols. Conjoined twins and twin-reversed arterial perfusion sequence (TRAPS) were excluded from structural anomalies. The diagnostic performance of first-trimester ultrasound in detection of fetal structural anomalies in twins was determined and compared with that of second trimester. The accuracy of independent variates associated with structural anomaly detection was calculated.

RESULTS

A total of 1442 women with twin pregnancies were included. In 40 women and 45 fetuses, structural anomalies were found. Fetal structural anomalies verified at delivery were detected in 42.5% (17/40) of affected pregnancies in the first trimester and 92.5% (37/40) of affected pregnancies when added second trimester (P = .13). The survival rate of pregnancies detected in second trimester was higher than that of pregnancies detected in first trimester (11.8% vs 65.2%). The mean value of intertwin CRL/NT discordance in cases with fetal structural anomalies was larger in monochorionic twins than dichorionic twins, but monochorionicity was not associated with structural anomalies. CRL discordance ≥10% (OR 3.1, 95%CI 1.5-6.3) and NT ≥95th centile (OR 20.0, 95%CI 9.0-44.2) were associated with fetal structural anomalies. In both dichorionic (DC) and monochorionic (MC) twins, the percentages of CRL discordance ≥10% was larger in twins with structural anomalies than those without structural anomalies (37.5% vs 13.4% in DC twins and 50.0% vs 12.5% in MC twins), and this was also true for NT ≥95th centile (31.3% vs 1.7% in DC twins and 37.5% vs 2.2% in MC twins). In the setting of CRL discordance ≥10%, 40.0% (16/40) of twins with structural anomalies were found, in which the predominant fetal structural anomalies were cardiovascular defects, abdominal wall defects, and central nervous system defects. The AUC for detecting structural anomalies by CRL discordance ≥10% was 0.63. In the setting of NT ≥95th centile, 32.5% (13/40) of twins with structural anomalies were found, in which the predominant fetal structural anomalies were cardiovascular defects, cystic hygroma, and abdominal wall defects. The AUC for detecting structural anomalies by NT ≥95th centile was 0.65.

CONCLUSIONS

The detection rate of twins with fetal structural anomalies was 42.5% per pregnancy in the first trimester. CRL discordance ≥10% and NT ≥95th centile may indicate higher risk of fetal structural anomalies in twins, but their efficacy was limited.

Should twin-specific growth charts be used to assess fetal growth in twin pregnancies?

One of the hallmarks of twin pregnancies is the slower rate of fetal growth when compared with singleton pregnancies during the third trimester. The mechanisms underlying this phenomenon and whether it represents pathology or benign physiological adaptation are currently unclear. One important implication of these questions relates to the type growth charts that should be used by care providers to monitor growth of twin fetuses. If the slower growth represents pathology (ie, intrauterine growth restriction caused uteroplacental insufficiency), it would be preferable to use a singleton growth chart to identify a small twin fetus that is at risk for perinatal mortality and morbidity. If, however, the relative smallness of twins is the result of benign adaptive mechanisms, it is likely preferable to use a twin-based charts to avoid overdiagnosis of intrauterine growth restriction in twin pregnancies. In the current review, we addressed this question by describing the differences in fetal growth between twin and singleton pregnancies, reviewing the current knowledge regarding the mechanisms responsible for slower fetal growth in twins, summarizing available empirical evidence on the diagnostic accuracy of the 2 types of charts for intrauterine growth restriction in twin pregnancies, and addressing the question of whether uncomplicated dichorionic twins are at an increased risk for fetal death when compared with singleton fetuses. We identified a growing body of evidence that shows that the use of twin charts can reduce the proportion of twin fetuses identified with suspected intrauterine growth restriction by up to 8-fold and can lead to a diagnosis of intrauterine growth restriction that is more strongly associated with adverse perinatal outcomes and hypertensive disorders than a diagnosis of intrauterine growth restriction based on a singleton-based chart without compromising the detection of twin fetuses at risk for adverse outcomes caused by uteroplacental insufficiency. We further found that small for gestational age twins are less likely to experience adverse perinatal outcomes or to have evidence of uteroplacental insufficiency than small for gestational age singletons and that recent data question the longstanding view that uncomplicated dichorionic twins are at an increased risk for fetal death caused by placental insufficiency. Overall, it seems that, based on existing evidence, the of use twin charts is reasonable and may be preferred over the use of singleton charts when monitoring the growth of twin fetuses. Still, it is important to note that the available data have considerable limitations and are primarily derived from observational studies. Therefore, adequately-powered trials are likely needed to confirm the benefit of twin charts before their use is adopted by professional societies.

A Systematic Review of the Safety of Blocking the IL-1 System in Human Pregnancy

Blockade of the interleukin-1 (IL-1) pathway has been used therapeutically in several inflammatory diseases including arthritis and cryopyrin-associated periodic syndrome (CAPS). These conditions frequently affect women of childbearing age and continued usage of IL-1 specific treatments throughout pregnancy has been reported. IL-1 is involved in pregnancy complications and its blockade could have therapeutic potential. We systematically reviewed all reported cases of IL-1 blockade in human pregnancy to assess safety and perinatal outcomes. We searched several databases to find reports of specific blockade of the IL-1 pathway at any stage of pregnancy, excluding broad spectrum or non-specific anti-inflammatory intervention. Our literature search generated 2439 references of which 22 studies included, following extensive review. From these, 88 different pregnancies were assessed. Most (64.8%) resulted in healthy term deliveries without any obstetrical/neonatal complications. Including pregnancy exposed to Anakinra or Canakinumab, 12 (15.0%) resulted in preterm birth and one stillbirth occurred. Regarding neonatal complications, 2 cases of renal agenesis (2.5%) were observed, and 6 infants were diagnosed with CAPS (7.5%). In conclusion, this systematic review describes that IL-1 blockade during pregnancy is not associated with increased adverse perinatal outcomes, considering that treated women all presented an inflammatory disease associated with elevated risk of pregnancy complications.

Haemophagocytic lymphohistiocytosis in pregnancy

Haemophagocytic lymphohistiocytosis is a life-threatening systemic inflammatory syndrome defined by persistent fever, cytopenia and multi-organ dysfunction. Primary haemophagocytic lymphohistiocytosis classically presents in childhood as a result of genetically abnormal perforin or inflammasome function, leading to the aberrant release of pro-inflammatory cytokines causing a hyperinflammatory state. Secondary haemophagocytic lymphohistiocytosis is an acquired phenomenon occurring at any age as a result of immune dysregulation to a specific trigger such as infection, haematological malignancy or autoimmune disease. Secondary haemophagocytic lymphohistiocytosis occurring in the pregnant woman represents a diagnostic challenge and carries a significant mortality. This has led to its first inclusion in the fourth Mothers and Babies: Reducing Risk through Audits and Confidential Enquiries across the United Kingdom annual maternal report in 2017. This article presents an overview of haemophagocytic lymphohistiocytosis, reviews the literature on haemophagocytic lymphohistiocytosis in pregnancy, suggests diagnostic pathways and explores the safety and efficacy of existing and potential treatment strategies for haemophagocytic lymphohistiocytosis occurring during pregnancy.

Maternal risk factors for the VACTERL association: A EUROCAT case-control study

BACKGROUND

The VACTERL association (VACTERL) is the nonrandom occurrence of at least three of these congenital anomalies: vertebral, anal, cardiac, tracheoesophageal, renal, and limb anomalies. Despite suggestions for involvement of several genes and nongenetic risk factors from small studies, the etiology of VACTERL remains largely unknown.

OBJECTIVE

To identify maternal risk factors for VACTERL in offspring in a large European study.

METHODS

A case-control study was performed using data from 28 EUROCAT registries over the period 1997-2015 with case and control ascertainment through hospital records, birth and death certificates, questionnaires, and/or postmortem examinations. Cases were diagnosed with VACTERL, while controls had a genetic syndrome and/or chromosomal abnormality. Data collected included type of birth defect and maternal characteristics, such as age, use of assisted reproductive techniques (ART), and chronic illnesses. Multivariable logistic regression analyses were performed to estimate confounder adjusted odds ratios (aOR) with 95% confidence intervals (95% CI).

RESULTS

The study population consisted of 329 VACTERL cases and 49,724 controls with recognized syndromes or chromosomal abnormality. For couples who conceived through ART, we found an increased risk of VACTERL (aOR 2.3 [95% CI 1.3, 3.9]) in offspring. Pregestational diabetes (aOR 3.1 [95% CI 1.1, 8.6]) and chronic lower obstructive pulmonary diseases (aOR 3.9 [95% CI 2.2, 6.7]) also increased the risk of having a child with VACTERL. Twin pregnancies were not associated with VACTERL (aOR 0.6 [95% CI 0.3, 1.4]).

CONCLUSION

We identified several maternal risk factors for VACTERL in offspring befitting a multifactorial etiology.

[Association between maternal age and adverse pregnancy outcome in twin pregnancy]

OBJECTIVE

To study the association between maternal age and adverse pregnancy outcome in twin pregnancy.

METHODS

The clinical data of 2 363 women with twin pregnancy from January 2006 to June 2016 were retrospectively reviewed. According to the age, the women were divided into six groups: <20 years (n=15), 20-24 years (n=158), 25-29 years (n=894), 30-34 years (n=936), 35-39 years (n=320), and ≥40 years group (n=40). The above groups were compared in terms of related baseline features and incidence rates of adverse pregnancy outcomes (preterm birth, birth defect, stillbirth in late pregnancy and small-for-gestational-age birth). A generalized estimating equation was used to investigate the risk of adverse pregnancy outcomes in different age groups.

RESULTS

After control for the factors including place of residence, primipara, pregnancy pattern, and gestational diseases, the incidence rates of very preterm birth and moderately preterm birth in the ≥40 years group were 2.60 and 1.99 times than those in the 25-29 years group respectively (P<0.05). The incidence rates of very preterm birth and late preterm birth in the 20-24 years group were 1.99 and 1.33 times than those in the 25-29 years group respectively (P<0.05). The incidence rates of stillbirth in late pregnancy in the <20 years group, the 20-24 years group, and the ≥40 years group were 9.10, 2.88 and 3.97 times than those in the 25-29 years group respectively (P<0.05). The incidence rates of small-for-gestational-age birth in the <20 years group and the 35-39 years group were 2.70 and 0.73 times than those in the 25-29 years group respectively (P<0.05).

CONCLUSIONS

In twin pregnancy, pregnant women, aged <20 years, have a higher risk of smaller-for-gestational-age birth and stillbirth in late pregnancy, those aged ≥40 years have a higher risk of very preterm birth, moderately preterm birth and stillbirth in late pregnancy, and those aged 20-24 years have a higher risk of very preterm birth, late preterm birth and stillbirth in late pregnancy.

Prevalence and descriptive epidemiology of infantile hypertrophic pyloric stenosis in the United States: A multistate, population-based retrospective study, 1999-2010

BACKGROUND

Antecedents for infantile hypertrophic pyloric stenosis (IHPS) vary across studies; therefore, we conducted a multistate, population-based retrospective study of the prevalence and descriptive epidemiology of IHPS in the United States (US).

METHODS

Data for IHPS cases (n = 29,554) delivered from 1999-2010 and enumerated from 11 US population-based birth defect surveillance programs, along with data for live births (n = 14,707,418) delivered within the same birth period and jurisdictions, were analyzed using Poisson regression to estimate IHPS prevalence per 10,000 live births. Additional data on deliveries from 1999-2005 from seven of these programs were analyzed using multivariable logistic regression to estimate adjusted prevalence ratios (aPR)s and 95% confidence intervals (CI)s for selected infant and parental characteristics.

RESULTS

Overall, IHPS prevalence from 1999-2010 was 20.09 (95% CI = 19.87, 20.32) per 10,000 live births, with statistically significant increases from 2003-2006 and decreases from 2007-2010. Compared to their respective referents, aPRs were higher in magnitude for males, preterm births, and multiple births, but lower for birth weights <2,500 g. The aPRs for all cases increased with decreasing parental age, maternal education, and maternal parity, but decreased for parental race/ethnicity other than non-Hispanic White. Estimates restricted to isolated cases or stratified by infant sex were similar to those for all cases.

CONCLUSIONS

This study covers one of the largest samples and longest temporal period examined for IHPS in the US. Similar to findings reported in Europe, estimates suggest that IHPS prevalence has decreased recently in the US. Additional analyses supported associations with several infant and parental characteristics.

Obstetric outcomes of twin pregnancies at advanced maternal age: A retrospective study

OBJECTIVE

To evaluate obstetric outcomes in twin pregnancies of advanced maternal age (≥35 years).

MATERIALS AND METHODS

A retrospective study involved 470 twin pregnancies in a single center from Sep. 1, 2012 to Mar. 31, 2015. Clinical characteristics and obstetric outcomes were recorded and compared among twin pregnancies who were classified as follows: age 20-29, 30-34, 35-39 and ≥40 years.

RESULTS

The incidence of gestational diabetes (age 20-29 years 15.8%; 30-34 years 24.3%; 35-39 years 30.4%; ≥40 years 57.1%; p = 0.004) and premature delivery (20-29 years 58.6%; 30-34 years 69.1%; 35-39 years 72.2%; ≥40 years 85.7%; p = 0.001) significantly increased with increasing age whereas spontaneous abortion (20-29 years 27.6%; 30-34 years 11.6%; 35-39 years 11.4%; ≥40 years 0.0%; p = 0.021) decreased in twin pregnancies of advanced maternal age. In addition, the rate of postpartum hemorrhage increased almost continuously by age and advanced maternal age was described as a risk factor for postpartum hemorrhage (age 35-39, adjusted OR 3.377; 95% confidence interval 1729-6.598; p < 0.001; age ≥ 40, adjusted OR 10.520; 95% CI 1.147-96.492; p = 0.037). However, there was no significant difference between advanced maternal age and adverse neonatal outcomes.

CONCLUSION

In twin pregnancies, advanced maternal age experienced significant higher risk of postpartum hemorrhage, gestational diabetes and premature delivery. Neither adverse neonatal outcomes nor stillbirth was significantly associated with maternal age.

Cohort Variation in Selection During Pregnancy and Risk of Selected Birth Defects Among Males

BACKGROUND

The literature theorizes, but does not test, that variation over time in selective loss in utero affects the observed count of live-born birth defects cases. We test the hypothesis that the risk of birth defects among live-born males varies inversely with the strength of selection against males in utero.

METHODS

We identified a subset of six birth defect phenotypes among males from the California Birth Defects Monitoring Program, an active surveillance system for over 490,000 male singletons born in eight California counties from 1986 to 2004. We assigned each birth defect case infant to a monthly conception cohort at risk of selection in utero. We used the monthly sex ratio at birth (M:F), derived from each conception cohort, as the indicator of selection against males. We analyzed the odds ratio of birth defects with both individual-level logistic regression and aggregate time-series methods.

RESULTS

Consistent with selection in utero, male infants from conception cohorts with low outlying sex ratios (i.e., stronger selectivity) exhibit fewer than expected birth defects (adjusted odds ratio [OR] = 0.86; 95% confidence interval [CI] = 0.76, 0.98). Aggregate time-series tests also yield similar findings (OR = 0.81; 95% CI = 0.71, 0.90).

CONCLUSIONS

Our findings among males indicate that variation in the strength of selectivity in utero accounts for a portion of observed cohort differences in morbidity due to birth defects. These findings suggest that "revealed prevalence" of morbidity across birth cohorts varies, at least in part, from selective loss in utero. See video abstract at, http://links.lww.com/EDE/B209.

International multi-centre study of pregnancy outcomes with interleukin-1 inhibitors

Objective

To provide outcome data concerning pregnancies exposed to the Interleukin-1 (IL-1) inhibitors prior to conception in both men and women, during pregnancy and breast feeding.

Methods

Retrospective data were collected from members of the International Society for Systemic Autoinflammatory diseases and collated in a single centre. A uniform data collection sheet was used to obtain standardized data including maternal age and diagnosis, type, duration of and response to IL-1 blockade, pregnancy duration, delivery, mode of feeding and neonatal development.

Results

There were 31 maternal-exposed pregnancies from seven countries and we report the first data on paternal exposure: six to anakinra and five to canakinumab, with no negative outcomes. We also report the first data on canakinumab-exposed pregnancies: eight pregnancies that resulted in the delivery of seven healthy infants of normal gestational age and birthweight. There were 23 anakinra-exposed pregnancies resulting in the birth of 21 healthy infants, and one baby with unilateral renal agenesis and ectopic neurohypophysis. There were two first trimester miscarriages affecting a mother with active disease. There were no serious neonatal infections. Fourteen infants were breast fed with no complications. There were no reports of developmental delay, with follow-up of up to 10 years (median 18 months).

Conclusion

This series substantially increases the published experience of IL-1 blockade and reproduction including the first data on canakinumab and on paternal exposure to these agents. Data are generally reassuring, although the case of renal agenesis is the second reported in an anakinra-exposed pregnancy.

Sensitivity of first-trimester ultrasound in the detection of congenital anomalies in twin pregnancies: population study and systematic review

INTRODUCTION

The first aim of this study was to ascertain the diagnostic performance of first-trimester ultrasound in detecting congenital anomalies in twins. The secondary aim was to explore the strength of association between different pregnancy characteristics and early detection of structural anomalies in a large unselected population of twin pregnancies. A systematic review of the published literature was also carried out.

MATERIAL AND METHODS

Retrospective analysis of prospectively collected data from consecutive twin pregnancies booked for antenatal care between 1996 and 2014. Predictive accuracy of those covariates independently associated with the occurrence of fetal anomalies was assessed with logistic regression analysis and receiver operating characteristics curves.

RESULTS

In all, 1064 twin pregnancies (820 dichorionic and 264 monochorionic) were included in the analysis. Forty-two pregnancies had one or more fetuses with structural abnormalities. Detection of structural abnormalities using ultrasound was possible in the first trimester in 27.3% (95% confidence interval 15.0-42.8) of twin pregnancies. Monochorionicity (odds ratio 2.3, 95% confidence interval 1.1-4.7) and discordance in crown-rump length and nuchal translucency were associated with an increased risk of fetal anomalies. However, their predictive accuracy was only moderate (areas under the curve 0.67, 95% confidence interval 0.6-0.8 and 0.68, 95% confidence interval 0.6-0.8, for crown-rump length and nuchal translucency discrepancy, respectively).

CONCLUSIONS

First-trimester detection of structural abnormalities in twin pregnancies is possible in 27.3% (95% confidence interval 15.0-42.8) of cases. The likelihood for first-trimester detection of structural anomalies in twins was maximum for cranial vault, midline brain and abdominal wall defects. Monochorionicity and increasing discrepancy in crown-rump length and nuchal translucency were associated with fetal structural abnormalities, although their predictive performance was only moderately good.

Twinning and major birth defects, National Birth Defects Prevention Study, 1997-2007

BACKGROUND

Twinning has been associated with many types of birth defects, although previous studies have had inconsistent findings. Many studies lack information about potential confounders, particularly use of fertility treatment. Our objective was to assess the association between twinning and birth defects in the National Birth Defects Prevention Study (NBDPS).

METHODS

We used data from the NBDPS, a population-based, case-control study of major birth defects in the USA, to evaluate associations between twinning and birth defects. The study population included mothers of twin and singleton controls (live-born infants without major birth defects), and cases (fetuses or infants with a major birth defect) born October 1997-December 2007. Adjusted ORs and 95% CIs were estimated using multivariable logistic regression stratified by use of fertility treatment. Twin sex-pairing data and a simulation approach were used to estimate the zygosity of twins.

RESULTS

In the unassisted conception stratum, we observed significant positive associations between twinning and 29 of 45 defect groups. The largest effect estimates were observed for multiple ventricular septal defects and cloacal exstrophy. Among mothers reporting any use of fertility treatments, we observed a significant association with twinning for 5 of 25 defect groups, with the largest effect estimates for hypoplastic left heart syndrome and omphalocele. OR estimates in the estimated monozygotic stratum were generally further from the null than in the dizygotic stratum.

CONCLUSIONS

Compared with singletons, a wide range of birth defects are significantly more common among twins. Birth defect risk in twins may be differential by use of fertility treatment.

Higher Incidence of Hypospadias in Monochorionic Twins

Background:Hypospadias is associated with twinning. The incidence of hypospadias in monochorionic and dichorionic male twins is, however, yet to be determined.Methods:All medical records of monochorionic and dichorionic twins admitted to our neonatal nursery between January 2004 and August 2013 were reviewed for the presence of hypospadias.Results:A total of 350 monochorionic and 303 dichorionic male twins were included in the study. The incidence of hypospadias in monochorionic and dichorionic groups was 4% (14/350) and 1% (3/303) (p= .016) respectively. In 11 of the 15 twin couples, hypospadias occurred in the twin with the lowest birth weight. The rate of hypospadias in twin infants small-for-gestational-age group was 10% (6/60) compared with 2% (11/593) in the appropriate-for-gestational-age group (p= .002). In a multivariate analysis, both monochorionicity and small-for-gestational-age were independently associated with hypospadias, odds ratio 4.1 (95% confidence interval (CI): 1.1–14.7) and 6.1 (95% CI: 2.2–17.2) respectively.Conclusions: The incidence of hypospadias is four-fold higher in monochorionic twins compared with dichorionic twins. Hypospadias is also independently associated with small-for-gestational-age.

Anakinra use during pregnancy in patients with cryopyrin-associated periodic syndromes (CAPS)

Objective: To describe the pregnancy course and outcome, and use of anakinra, a recombinant selective IL-1 receptor blocker, during pregnancy in patients with cryopyrin-associated periodic syndromes (CAPS), including familial cold auto-inflammatory syndrome (FCAS), Muckle-Wells syndrome (MWS) and neonatal onset multi-system inflammatory disease (NOMID). Methods: Women currently enrolled in natural history protocols (NCT00059748, and/or NCT00069329 under IND) who have been pregnant were included. Subjects underwent a structured, standardized interview with regards to maternal health, pregnancy and fetal outcomes. Medical records were reviewed. Results: Nine women (four with FCAS, one with MWS and four with NOMID) reported one to four pregnancies, each resulting in a total of fifteen FCAS, three MWS, and six NOMID pregnancies. Six births from FCAS mothers and three births from NOMID mothers occurred while patients were receiving anakinra. If a woman became pregnant while taking anakinra, the pre-pregnancy anakinra dose was continued. Anakinra dose was increased during one twin pregnancy. No preterm births or serious complications of pregnancy were observed. One fetus of the twin pregnancy had renal agenesis and suffered fetal demise. Genetic testing showed the deceased twin carried the same NLRP3 c.785T>C, p.V262A mutation as the mother. The other twin is healthy and mutation negative. Conclusions: Anakinra was continued during pregnancy in women with CAPS and provided significant, persistent CAPS symptom relief while continuing to prevent the long-term sequelae of CAPS. Anakinra was well tolerated. Although a causal relation between anakinra and renal agenesis seems unlikely, further safety data are needed.

Psychosocial job strain and risk of congenital malformations in offspring--a Danish National cohort study

OBJECTIVE

To investigate if maternal exposure to psychosocial job strain at work (high demands and low control) measured by questionnaire early in pregnancy (median week 15) is associated with malformations in the offspring.

DESIGN

Population-based cohort study.

SETTING

The Danish National Birth Cohort.

POPULATION

A cohort of 60,386 singleton children with full information on mother's occupational status, exposure to psychosocial job strain and all covariates during pregnancy.

METHODS

Logistic regression analysis was used to calculate the odds of congenital malformations as a function of job strain with adjustment for maternal age, body mass index, parity, smoking, alcohol use, manual versus nonmanual work, maternal serious disease and gestational age at interview.

MAIN OUTCOME MEASURES

Circulatory malformation, musculoskeletal malformation or any malformation.

RESULTS

Logistic regression analyses, both crude and adjusted, indicated no associations between working under high strain and giving birth to a child with circulatory malformation (adjusted odds ratio [OR] 1.04, 95% confidence interval [95% CI] 0.75-1.44), musculoskeletal malformation (aOR 0.88, 95% CI 0.71-1.10) or any malformation (aOR 0.99, 95% CI 0.85-1.15). Supplementary analyses including restriction to first-borns and a stratified analysis with respect to manual and nonmanual work did not change the results.

CONCLUSIONS

Association between exposure to high job strain during pregnancy and elevated risk of circulatory, muscle and any malformations is not supported by this study.