Sex prevalence of major congenital anomalies in the United Kingdom: a national population-based study and international comparison meta-analysis

Interpregnancy interval and birth defects

BACKGROUND

Interpregnancy interval is a risk factor for various adverse birth outcomes including birth defects. We investigated the relationship between interpregnancy interval and birth defects.

METHODS

We conducted a retrospective cohort study using linked data from Nevada Birth Outcomes Monitoring System and birth certificate data for 124,341 singleton live births, of which 4641 infants had 7192 birth defects, among Nevada resident women between 2006 and 2011. We used logistic regression to assess factors independently associated with birth defects.

RESULTS

Women who had an interpregnancy interval of 36 months or more, adjusted odds ratio (AOR) = 1.16, 95% confidence interval [CI], 1.01-1.33, were more likely to have an infant with a birth defect compared with women with an interpregnancy interval of 18 to 23 months. Other independent risk factors for birth defects included male infants, AOR = 1.34, 95% CI, 1.26-1.42; maternal age (30-34 years) and advanced maternal age (35 years and older), AOR = 1.10, 95% CI, 1.01-1.19 and AOR = 1.29, 95% CI, 1.18-1.42, respectively; being a Black woman, AOR = 1.46, 95% CI, 1.32-1.61; three and four or more previous births, AOR = 1.12, 95% CI, 1.02-1.23 and AOR = 1.24, 95% CI, 1.11-1.38, respectively; smoking, AOR = 1.23, 95% CI, 1.10-1.38; and prescription drug use, AOR = 1.14, 95% CI, 1.07-1.21.

CONCLUSION

A long interpregnancy interval is an independent risk factor for birth defects. It may be helpful for maternal and child health programs and health care providers to highlight the deleterious effects of a long interpregnancy interval.

Changes in the Incidence of Congenital Anomalies in Henan Province, China, from 1997 to 2011

Aim

To investigate changes in incidence and characteristics of congenital anomalies in infants in Henan Province of China over a period of 15 years.

Methods

Population-based surveillance in Henan Province was conducted from 1997 to 2011 in 75 hospitals (40 urban districts and 35 rural counties, comprising about 20% of the total births). Basic population information was obtained from the healthcare network. All live births, intrauterine deaths after 28 weeks, and stillbirths were included. Congenital anomalies were diagnosed and reported to Henan Provincial Maternal and Pediatric Healthcare Hospital.

Results

Of 1,815,920 births from 1997 to 2011, 15,660 cases of congenital anomalies were identified, resulting in an average incidence of 86.2 cases per 10,000 births. The incidence of congenital anomalies showed a significant downward trend (p < 0.0001) in rural areas and the whole province (p < 0.0001), but an increase in urban areas (p = 0.003). The incidence was much higher in rural than in urban areas in 1997, but this discrepancy decreased rapidly and no difference was seen between rural and urban areas in 2003. The incidence in females was higher than in males in 1997–1999 but decreased to a similar level as that in males in 2000. Maternal age exceeding 35 years was associated with a higher incidence of congenital anomalies. Among the 23 types of congenital anomalies recorded, neural tube defects were the most common; the incidence declined from 39.3 cases per 10,000 births in 1997 to 6.1 cases per 10,000 births in 2011.

Conclusion

The incidence of congenital anomalies has decreased in Henan Province over the past 15 years due to significant reductions in rural areas and among girls. This decrease was partly related to a reduction in neural tube defects that was likely the result of a folic acid intervention in the province.

Sex ratios among infants with birth defects, National Birth Defects Prevention Study, 1997-2009

A small number of population-based studies have examined sex differences among infants with birth defects. This study presents estimates of sex ratio for both isolated cases and those with multiple congenital anomalies, as well as by race/ethnicity. Male-female sex ratios and their 95% confidence intervals were calculated for 25,952 clinically reviewed case infants included in the National Birth Defects Prevention Study (1997-2009), a large population-based case-control study of birth defects. The highest elevations in sex ratios (i.e., male preponderance) among isolated non-cardiac defects were for craniosynostosis (2.12), cleft lip with cleft palate (2.01), and cleft lip without cleft palate (1.78); the lowest sex ratios (female preponderance) were for choanal atresia (0.45), cloacal exstrophy (0.46), and holoprosencephaly (0.64). Among isolated cardiac defects, the highest sex ratios were for aortic stenosis (2.88), coarctation of the aorta (2.51), and d-transposition of the great arteries (2.34); the lowest were multiple ventricular septal defects (0.52), truncus arteriosus (0.63), and heterotaxia with congenital heart defect (0.64). Differences were observed by race/ethnicity for some but not for most types of birth defects. The sex differences we observed for specific defects, between those with isolated versus multiple defects, as well as by race/ethnicity, demonstrate patterns that may suggest etiology and improve classification.

Laterality defects in the national birth defects prevention study (1998-2007): birth prevalence and descriptive epidemiology

Little is known epidemiologically about laterality defects. Using data from the National Birth Defects Prevention Study (NBDPS), a large multi-site case-control study of birth defects, we analyzed prevalence and selected characteristics in children born with laterality defects born from 1998 to 2007. We identified 517 nonsyndromic cases (378 heterotaxy, 73.1%; 139 situs inversus totalis [SIT], 26.9%) resulting in an estimated birth prevalence of 1.1 per 10,000 live births (95% confidence interval 1.0–1.2). Prevalence did not differ significantly across sites, over time, or by inclusion of pregnancy termination. Laterality defects were more common among preterm cases compared to term cases, and in children born to mothers who were non-white or younger than 20 years compared to white mothers or those age 25–29 years. The distribution of associated cardiac and extra-cardiac defects, excluding the expected heterotaxy anomalies, varied by type of laterality defect. Cases with heterotaxy were significantly more likely than those with SIT to have double outlet right ventricle, atrioventricular canal defects, pulmonary stenosis, non-tetralogy of Fallot pulmonary atresia with ventricular septal defect, totally and partially anomalous pulmonary venous return; also more likely to have orofacial clefts, esophageal atresia, bowel atresias, and omphalocele, though not reaching statistical significance. Relatively more common among cases with SIT were Dandy- Walker malformation, anotia/microtia, and limb deficiency. The similarity in the demographic characteristics of heterotaxy and SIT supports the hypothesis that they are part of a continuum of abnormal left-right axis patterning. These findings on laterality defects may help guide clinical care, future research, and prevention strategies.