[Risk factors for congenital anal atresia]

Fetal deaths from birth defects in Hunan Province, China, 2016-2020

To describe the fetal death rate of birth defects (including a broad range of specific defects) and to explore the relationship between fetal deaths from birth defects and a broad range of demographic characteristics. Data was derived from the birth defects surveillance system in Hunan Province, China, 2016-2020. Fetal death refers to the intrauterine death of a fetus at any time during the pregnancy, including medical termination of pregnancy. Fetal death rate is the number of fetal deaths per 100 births (including live births and fetal deaths) in a specified group (unit: %). The fetal death rate of birth defects with 95% confidence intervals (CI) was calculated by the log-binomial method. Crude odds ratios (ORs) were calculated to examine the relationship between each demographic characteristic and fetal deaths from birth defects. This study included 847,755 births, and 23,420 birth defects were identified. A total of 11,955 fetal deaths from birth defects were identified, with a fetal death rate of 51.05% (95% CI 50.13-51.96). 15.78% (1887 cases) of fetal deaths from birth defects were at a gestational age of < 20 weeks, 59.05% (7059 cases) were at a gestational age of 20-27 weeks, and 25.17% (3009 cases) were at a gestational age of ≥ 28 weeks. Fetal death rate of birth defects was higher in females than in males (OR = 1.25, 95% CI 1.18-1.32), in rural than in urban areas (OR = 1.43, 95% CI 1.36-1.50), in maternal age 20-24 years (OR = 1.35, 95% CI 1.25-1.47), and ≥ 35 years (OR = 1.19, 95% CI 1.11-1.29) compared to maternal age of 25-29 years, in diagnosed by chromosomal analysis than ultrasound (OR = 6.24, 95% CI 5.15-7.55), and lower in multiple births than in singletons (OR = 0.41, 95% CI 0.36-0.47). The fetal death rate of birth defects increased with the number of previous pregnancies (χ2trend = 49.28, P < 0.01), and decreased with the number of previous deliveries (χ2trend = 4318.91, P < 0.01). Many fetal deaths were associated with birth defects. We found several demographic characteristics associated with fetal deaths from birth defects, which may be related to the severity of the birth defects, economic and medical conditions, and parental attitudes toward birth defects.

Multivariate logistic regression analysis of risk factors for birth defects: a study from population-based surveillance data

OBJECTIVE

To explore risk factors for birth defects (including a broad range of specific defects).

METHODS

Data were derived from the Population-based Birth Defects Surveillance System in Hunan Province, China, 2014-2020. The surveillance population included all live births, stillbirths, infant deaths, and legal termination of pregnancy between 28 weeks gestation and 42 days postpartum. The prevalence of birth defects (number of birth defects per 1000 infants) and its 95% confidence interval (CI) were calculated. Multivariate logistic regression analysis (method: Forward, Wald, α = 0.05) and adjusted odds ratios (ORs) were used to identify risk factors for birth defects. We used the presence or absence of birth defects (or specific defects) as the dependent variable, and eight variables (sex, residence, number of births, paternal age, maternal age, number of pregnancies, parity, and maternal household registration) were entered as independent variables in multivariate logistic regression analysis.

RESULTS

Our study included 143,118 infants, and 2984 birth defects were identified, with a prevalence of 20.85% (95%CI: 20.10-21.60). Multivariate logistic regression analyses showed that seven variables (except for parity) were associated with birth defects (or specific defects). There were five factors associated with the overall birth defects. The risk factors included males (OR = 1.49, 95%CI: 1.39-1.61), multiple births (OR = 1.44, 95%CI: 1.18-1.76), paternal age < 20 (OR = 2.20, 95%CI: 1.19-4.09) or 20-24 (OR = 1.66, 95%CI: 1.42-1.94), maternal age 30-34 (OR = 1.16, 95%CI: 1.04-1.29) or > = 35 (OR = 1.56, 95%CI: 1.33-1.81), and maternal non-local household registration (OR = 2.96, 95%CI: 2.39-3.67). Some factors were associated with the specific defects. Males were risk factors for congenital metabolic disorders (OR = 3.86, 95%CI: 3.15-4.72), congenital limb defects (OR = 1.34, 95%CI: 1.14-1.58), and congenital kidney and urinary defects (OR = 2.35, 95%CI: 1.65-3.34). Rural areas were risk factors for congenital metabolic disorders (OR = 1.21, 95%CI: 1.01-1.44). Multiple births were risk factors for congenital heart defects (OR = 2.09, 95%CI: 1.55-2.82), congenital kidney and urinary defects (OR = 2.14, 95%CI: 1.05-4.37), and cleft lip and/or palate (OR = 2.85, 95%CI: 1.32-6.15). Paternal age < 20 was the risk factor for congenital limb defects (OR = 3.27, 95%CI: 1.10-9.71), 20-24 was the risk factor for congenital heart defects (OR = 1.64, 95%CI: 1.24-2.17), congenital metabolic disorders (OR = 1.56, 95%CI: 1.11-2.21), congenital limb defects (OR = 1.61, 95%CI: 1.14-2.29), and congenital ear defects (OR = 2.13, 95%CI: 1.17-3.89). Maternal age < 20 was the risk factor for cleft lip and/or palate (OR = 3.14, 95%CI: 1.24-7.95), 30-34 was the risk factor for congenital limb defects (OR = 1.37, 95%CI: 1.09-1.73), >=35 was the risk factor for congenital heart defects (OR = 1.51, 95%CI: 1.14-1.99), congenital limb defects (OR = 1.98, 95%CI: 1.41-2.78), and congenital ear defects (OR = 1.82, 95%CI: 1.06-3.10). Number of pregnancies = 2 was the risk factor for congenital nervous system defects (OR = 2.27, 95%CI: 1.19-4.32), >=4 was the risk factor for chromosomal abnormalities (OR = 2.03, 95%CI: 1.06-3.88) and congenital nervous system defects (OR = 3.03, 95%CI: 1.23-7.47). Maternal non-local household registration was the risk factor for congenital heart defects (OR = 3.57, 95%CI: 2.54-5.03), congenital metabolic disorders (OR = 1.89, 95%CI: 1.06-3.37), congenital limb defects (OR = 2.94, 95%CI: 1.86-4.66), and congenital ear defects (OR = 3.26, 95%CI: 1.60-6.65).

CONCLUSION

In summary, several risk factors were associated with birth defects (including a broad range of specific defects). One risk factor may be associated with several defects, and one defect may be associated with several risk factors. Future studies should examine the mechanisms. Our findings have significant public health implications as some factors are modifiable or avoidable, such as promoting childbirths at the appropriate age, improving the medical and socio-economic conditions of non-local household registration residents, and devoting more resources to some specific defects in high-risk groups, which may help reducing birth defects in China.

Perinatal deaths from birth defects in Hunan Province, China, 2010-2020

OBJECTIVE

To describe the perinatal mortality rate (PMR) of birth defects and to define the relationship between birth defects (including a broad range of specific defects) and a broad range of factors.

METHODS

Data were obtained from the Birth Defects Surveillance System in Hunan Province, China, 2010-2020. The prevalence rate (PR) of birth defects is the number of birth defects per 1000 fetuses (births and deaths at 28 weeks of gestation and beyond). PMR is the number of perinatal deaths per 100 fetuses. PR and PMR with 95% confidence intervals (CI) were calculated using the log-binomial method. Chi-square trend tests (χ2trend) were used to determine trends in PR and PMR by year, maternal age, income, education level, parity, and gestational age of termination. Crude odds ratios (ORs) were calculated to examine the association of each maternal characteristic with perinatal deaths attributable to birth defects.

RESULTS

Our study included 1,619,376 fetuses, a total of 30,596 birth defects, and 18,212 perinatal deaths (including 16,561 stillbirths and 1651 early neonatal deaths) were identified. The PR of birth defects was 18.89‰ (95%CI: 18.68-19.11), and the total PMR was 1.12%(95%CI: 1.11-1.14). Birth defects accounted for 42.0% (7657 cases) of perinatal deaths, and the PMR of birth defects was 25.03%. From 2010 to 2020, the PMR of birth defects decreased from 37.03% to 2010 to 21.00% in 2020, showing a downward trend (χ2trend = 373.65, P < 0.01). Congenital heart defects caused the most perinatal deaths (2264 cases); the PMR was 23.15%. PMR is highest for encephalocele (86.79%). Birth defects accounted for 45.01% (7454 cases) of stillbirths, and 96.16% (7168 cases) were selective termination of pregnancy. Perinatal deaths attributable to birth defects were more common in rural than urban areas (31.65% vs. 18.60%, OR = 2.03, 95% CI: 1.92-2.14) and in females than males (27.92% vs. 22.68%, OR = 1.32, 95% CI: 1.25-1.39). PMR of birth defects showed downward trends with rising maternal age (χ2trend = 200.86, P < 0.01), income (χ2trend = 54.39, P < 0.01), maternal education level (χ2trend = 405.66, P < 0.01), parity (χ2trend = 85.11, P < 0.01) and gestational age of termination (χ2trend = 15297.28, P < 0.01).

CONCLUSION

In summary, birth defects are an important cause of perinatal deaths. Rural areas, female fetuses, mothers with low maternal age, low income, low education level, low parity, and low gestational age of termination were risk factors for perinatal deaths attributable to birth defects. Future studies should examine the mechanisms. Our study is helpful for intervention programs to reduce the PMR of birth defects.

Association between maternal exposure to PM10 and risk of anorectal atresia/stenosis in offspring: a population-based case-control study in Liaoning Province, China

The potential association between maternal exposure to PM₁₀ ranging from 3 months prior to conception to the end of the early trimester and the risk of anorectal atresia/stenosis in offspring has not been established. Thus, we determined the association between maternal exposure to PM₁₀ and risk of anorectal atresia/stenosis in offspring in this study. We recruited 713 patients including 480 male and 233 female with anorectal atresia/stenosis and 7950 randomly selected healthy offspring from the Maternal and Child Health Certificate Registry of Liaoning Province and delivered between 1 January 2010 and 31 December 2015. Monthly PM₁₀ concentrations were retrieved from the Environment Protection Bureau of each city in Liaoning Province. We established a multivariable logistic regression model to calculate the adjusted odds ratios (ORs) and 95% confidence intervals (CIs). Maternal exposure to PM₁₀ was associated with an increased risk for anorectal atresia/stenosis in offspring during the 3 months prior to conception (per 10 μg/m³ increment: OR = 1.15, 95% CI = 1.03-1.20; per SD [27 μg/m³] increment: OR = 1.33, 95% CI = 1.09-1.63) and the first trimester (per 10 μg/m³ increment: OR = 1.08, 95% CI = 1.00-1.17; per SD [28 μg/m³] increment: OR = 1.26, 95% CI = 1.01-1.57). Evaluation of the association with a shorter exposure window (1 month) revealed a positive association between anorectal atresia/stenosis and PM₁₀ from the 3rd month prior to pregnancy to each month of the 1st trimester. Maternal exposure to PM₁₀ 3 months prior to conception and during the 1st trimester was associated with an increased risk of anorectal atresia/stenosis in the offspring. Future perspective cohort studies are needed to confirm our findings.