Value of sharing and networking among birth defects surveillance programs: an ICBDSR perspective

Orofacial Clefts and Maternal Risk Factors: A Population-Based Case-Control Study

BACKGROUND/OBJECTIVES

Orofacial clefts (OFCs) are some of the most common congenital anomalies worldwide. The aim of this case-control study was to evaluate the association of OFCs with selected maternal characteristics.

METHODS

Data on isolated non-syndromic cases of OFCs were extracted from the population-based registry of congenital anomalies of Tuscany. A sample of live-born infants without any congenital anomaly was used as the control group. We investigated the association with sex and some maternal characteristics: age, body mass index, smoking, and education. Adjusted odds ratios (OR) were calculated using a logistic regression model. Analyses were performed for the total OFCs and separately for cleft lip (CL) and cleft palate (CP).

RESULTS

Data on 219 cases and 37,988 controls were analyzed. A higher proportion of males (57.9%) was observed, particularly for CL. A decreasing trend among the maternal age classes was observed (OR:0.81 (95%CI 0.70-0.94)). Underweight mothers had a higher prevalence of OFCs, in particular for CL (OR:1.88 (95%CI 1.08-3.26)).

CONCLUSIONS

We found an association of OFCs with lower maternal age. The association with maternal age remains controversial and further epidemiological evidence is needed through multicenter studies. We observed that CL was more common in underweight mothers, suggesting actions of primary prevention.

Neural tube defects: a review of global prevalence, causes, and primary prevention

Neural tube defects (NTDs) are common birth defects and contribute to life-long disabilities, high medical care costs, and perinatal and child mortality. This review is a primer on prevalence, causes, and evidence-based prevention strategies for NTDs. The estimated average global prevalence of NTDs is two cases per 1000 births, amounting to approximately 214,000-322,000 affected pregnancies worldwide annually. Prevalence and associated adverse outcomes are disproportionately high in developing countries. NTDs have multiple risk factors including genetic and non-genetic (i.e., maternal nutritional status, pre-pregnancy diabetes, early pregnancy exposure to valproic acid (anti-epileptic medication), and a previous pregnancy affected by a NTD) factors. Maternal folate insufficiency before and during early pregnancy is the most common risk factor and is preventable. Folic acid (vitamin B9) is required for formation of the neural tube early in pregnancy, around 28 days after conception, when most women are unaware of their pregnancies. Current guidelines recommend that all women planning or capable of pregnancy take a daily supplement containing 400-800 μg of folic acid. Mandatory folic acid fortification of staple foods (e.g., wheat flour, maize flour, rice) is safe, economical, and the effective intervention for primary prevention of NTDs. Currently, about 60 countries are implementing mandatory folic acid fortification of staple foods, preventing just a quarter of all preventable NTD cases worldwide. There is an urgent need for active champions, including neurosurgeons and other healthcare providers, to generate political will and promote effective mandatory food fortification with folic acid, and reach equitable primary prevention of NTDs in all countries.

Maternal exposure to particulate matter early in pregnancy and congenital anomalies in offspring: Analysis of concentration-response relationships in a population-based cohort with follow-up throughout childhood

Studies have suggested an association between particulate matter (PM) air pollution and certain congenital anomalies (CAs). However, most studies assumed a linear concentration-response relation and were based on anomalies that were ascertained at birth or up to 1 year of age. We investigated associations between exposures to PM during the first trimester of pregnancy and CAs in 9 organ systems using birth and childhood follow-up data from a leading health care provider in Israel. We conducted a retrospective population-based cohort study among 396,334 births, 2004-2015. Daily PM data at a 1 × 1 km spatial grid were obtained from a satellite-derived prediction models and were linked to the mothers' residential addresses at birth. Adjusted odds ratios (ORs) were estimated with logistic regression models using exposure levels as either continuous or categorical variables. We captured 57,638 isolated CAs with estimated prevalence of 96 and 136 anomalies per 1000 births in the first year of life and by age 6 years, respectively. Analysis of continuous PM with diameter < 2.5 μm (PM_2.5) indicated a supra-linear relation with anomalies in the circulatory, respiratory, digestive, genital and integument systems (79 % of CAs). The slope of the concentration-response function was positive and steepest for PM_2.5 lower than the median concentration (21.5 μg/m³) and had a less steep or negative slope at higher levels. Similar trends were observed for PM_2.5 quartiles. For example, for cardiac anomalies, the ORs were 1.09 (95 % confidence interval: 1.02, 1.15), 1.04 (0.98, 1.10) and 1.00 (0.94, 1.07) for births in the second, third and fourth quartiles, respectively, when compared to the first quartile. In sum, this study adds new evidence for adverse effects of air pollution on neonatal health even with low-level air pollution. Information on late diagnosis of children with anomalies is important in evaluating the burden of disease.

Association between maternal body mass index and congenital anomalies: A case-control study in Tuscany (Italy)

OBJECTIVE

To investigate the relationship between prepregnancy maternal body mass index (BMI) and congenital anomalies (CAs).

DESIGN

Case-control study on data collected by the registry of CAs of Tuscany (Italy) and birth certificates from 2005 to 2017.

MAIN EXPOSURE

Maternal prepregnancy BMI.

MAIN OUTCOME MEASURES

Any major CAs and groups of organ-specific anomalies. Odds ratios (ORs) were estimated using logistic regression models adjusted for maternal factors.

RESULTS

Maternal BMI ≥25 was significantly associated with all nervous system anomalies (OR = 1.61, 95% confidence interval [95% CI] 1.13-2.29) and with neural tube defects (OR = 2.03, 95% CI 1.00-4.12); maternal underweight was significantly associated with orofacial clefts (OR = 1.67, 95% CI 1.12-2.48). After stratification by education, in the low education group, mothers with BMI ≥25 had an increased risk of nervous system anomalies (OR = 2.19, 95% CI 1.01-4.76), whereas underweight mothers had an increased risk of nervous system anomalies (OR = 3.89, 95% CI 1.44-10.53), orofacial clefts (OR = 2.59, 95% CI 1.24-5.42), and urinary anomalies (OR = 1.74, 95% CI 1.07-2.82). In the medium/high education group, the only significantly increased risk was found in mothers with BMI ≥25 for nervous system anomalies (OR = 1.50, 95% CI 1.00-2.25).

CONCLUSION

Main results have shown a positive association of maternal BMI ≥25 with nervous system anomalies and maternal underweight with orofacial clefts. The study has also evidenced the impact of social status and provided clues to the role of maternal ethnic background.

Sociodemographic Differences in Prenatal Diagnosis of Chromosomal Anomalies: A Population-Based Study

Background: In Europe, about 76% of cases of chromosomal anomalies are prenatally diagnosed. Prenatal diagnosis allows more efficient planning of postnatal treatment and helps parents for an informed decision about the continuation of pregnancy. The main aim of this study was to evaluate whether the sociodemographic maternal characteristics affect the probability of prenatal diagnosis of chromosomal anomalies. Methods: Cases of chromosomal anomalies in the period 2005-2017 came from the population-based registry of congenital anomalies of Tuscany (Italy). Differences in the proportion of cases prenatally diagnosed were investigated through the following maternal characteristics: education, geographic origin and occupation. The association between cases of termination of pregnancy after prenatal diagnosis and maternal characteristics was also analysed. Odds Ratios (OR) adjusted by maternal age were calculated using logistic regression models. Results were provided for all cases of chromosomal anomalies and for Down syndrome cases. Results: A total of 1,419 cases were included in the study. Cases prenatally diagnosed were 1,186 (83.6%). We observed a higher proportion of cases not prenatally diagnosed among cases with low maternal education compared to those with high maternal education (OR = 2.16, p < 0.001) and in women from high migratory outflow countries, compared to the Italian ones (OR = 2.85, p < 0.001). For prenatally diagnosed Down syndrome cases, we observed a higher proportion of termination of pregnancy for women with low education level (OR = 4.36, p = 0.023). Conclusions: In our study evidence of differences in the probability of prenatal diagnosis of chromosomal anomalies associated with maternal education and geographic origin was found. Population-based studies investigating sociodemographic disparities can provide essential information for targeted public health programs. Further studies are recommended to monitor the impact of the increasing availability of non-invasive screening tests.

The Latin American network for congenital malformation surveillance: ReLAMC

The early detection of congenital anomaly epidemics occurs when comparing current with previous frequencies in the same population. The success of epidemiologic surveillance depends on numerous factors, including the accuracy of the rates available in the base period, wide population coverage, and short periodicity of analysis. This study aims to describe the Latin American network of congenital malformation surveillance: ReLAMC, created to increase epidemiologic surveillance in Latin America. We describe the main steps, tasks, strategies used, and preliminary results. From 2017 to 2019, five national registries (Argentina [RENAC], Brazil [SINASC/SIM-BRS], Chile [RENACH], Costa Rica [CREC], Paraguay [RENADECOPY-PNPDC]), six regional registries (Bogotá [PVSDC-Bogota], Cali [PVSDC-Cali], Maule [RRMC SSM], Nicaragua [SVDC], Nuevo-León [ReDeCon HU], São Paulo [SINASC/SIM-MSP]) and the ECLAMC hospital network sent data to ReLAMC on a total population of 9,152,674 births, with a total of 101,749 malformed newborns (1.1%; 95% CI 1.10-1.12). Of the 9,000,651 births in countries covering both live and stillbirths, 88,881 were stillborn (0.99%; 95% CI 0.98-0.99), and among stillborns, 6,755 were malformed (7.61%; 95% CI 7.44-7.79). The microcephaly rate was 2.45 per 10,000 births (95% CI 2.35-2.55), hydrocephaly 3.03 (2.92-3.14), spina bifida 2.89 (2.78-3.00), congenital heart defects 15.53 (15.27-15.79), cleft lip 2.02 (1.93-2.11), cleft palate and lip 2.77 (2.66-2.88), talipes 2.56 (2.46-2.67), conjoined twins 0.16 (0.14-0.19), and Down syndrome 5.33 (5.18-5.48). Each congenital anomaly showed heterogeneity in prevalence rates among registries. The harmonization of data in relation to operational differences between registries is the next step in developing the common ReLAMC database.