The Impact of Technology on the Diagnosis of Congenital Malformations

Loreen Straub; Krista F. Huybrechts; Brian T. Bateman; Helen Mogun; Kathryn J. Gray; Lewis B. Holmes; Sonia Hernandez-Diaz

Disclosures

Am J Epidemiol. 2019;188(11):1892-1901. 

In This Article

Results

Our cohort consisted of 1,448,703 women who contributed 1,780,156 pregnancies: 1,185,013 (81.8%) of these women contributed 1 pregnancy to our study cohort, 210,721 (14.5%) women contributed 2 pregnancies, and 52,969 (3.7%) contributed more than 2 pregnancies.

As shown in Figure 1A, none of the 6 negative controls showed temporal variations. Among the 6 selected malformations with a presumably high proportion of potentially technology-detected cases, the prevalence of secundum ASD, PDA, and VSD increased over time: from 2.3‰ in 2000 to 7.5‰ in 2013 for ASD, from 1.9‰ to 4.1‰ for PDA, and from 3.6‰ to 4.5‰ for VSD (Figure 1B; Table 1). Pulmonary artery anomalies, pulmonary valve stenosis, and congenital hydrocephalus did not show any trends over time. Web Table 2 provides more details on the overall and calendar-year–stratified prevalence of each malformation of interest.

Figure 1.

Trends in the prevalence (number of cases per 1,000 infants) of selected congenital malformations unlikely to escape clinical diagnosis ("negative controls") (A) and comprising a presumably high proportion of technology-detected cases ("case malformations") (B), per year of delivery, among 1,780,156 mother-infant pairs in a Medicaid Analytic eXtract pregnancy cohort, 2000–2013. Bars, 95% confidence intervals.

Severe or persistent cases of secundum ASD, PDA, and VSD accounted for a modest proportion of the cases of each of these malformations (41.4% for secundum ASD, 32.6% for PDA, and 19.3% for VSD), and their temporal trend was more moderate than that of the less severe cases (see Figure 2).

Figure 2.

Trends in the prevalence (number of cases per 1,000 infants) of secundum atrial septal defect (A), patent ductus arteriosus (B), and ventricular septal defect (C) per year of delivery, overall and by severity, among 1,780,156 mother-infant pairs in a Medicaid Analytic eXtract pregnancy cohort, 2000–2013. Bars, 95% confidence intervals.

Among the risk factors associated with the selected outcomes (Web Table 3), the prevalence of tobacco use, overweight or obesity, diabetes, hypertension, and advanced maternal age (≥35 years vs. <35 years) increased from 2000 to 2013 (e.g., diabetes from 1.6% to 2.5%, hypertension from 1.4% to 3.2%), whereas the frequency of multiple birth remained constant at approximately 2% and the frequency of preterm births at approximately 10%. We further observed changes in the racial/ethnic composition of women in our cohort, with the proportion of black women decreasing from 39.6% in 2000 to 29.4% in 2013. The relative frequency of women living in metropolitan areas versus urban or rural areas increased slightly in more recent years (from 82.1% to 87.7%). For more details, see Table 2 and Web Table 4.

We further observed increasing trends in pre- and postnatal imaging tests (Web Table 4): The prevalence of first-trimester ultrasound increased from 12.1% of all pregnancies in 2000 to 59.9% in 2013; during that same period, the prevalence of second- or third-trimester ultrasound increased from 79.5% to 90.0%, the prevalence of prenatal echocardiography increased from 2.8% to 7.1%, and the prevalence of postnatal cardiac imaging increased from 4.1% to 5.5%. The prevalence of 3-dimensional ultrasound increased from 0.3% in 2006, when codes for 3-dimensional screening became available, to 0.7% in 2013.

Results from the logistic regression analyses indicated that the observed prevalence increase of secundum ASD, PDA, and VSD could not be attributed to changes in the distribution of measured risk factors over time (Figure 3). However, accounting for increased use of prenatal screening and postnatal cardiac imaging tests did attenuate the predicted prevalence increase of secundum ASD and PDA and resulted in a stable prevalence of VSD over time.

Figure 3.

Trends in the predicted prevalence (number of cases per 1,000 infants) of secundum atrial septal defect (ASD) overall (A), severe secundum ASD (B), less severe/nonsevere secundum ASD (C), patent ductus arteriosus (PDA) overall (D), severe PDA (E), less severe/nonsevere PDA (F), ventricular septal defect (VSD) overall (G), severe VSD (H), and less severe/nonsevere VSD (I), per year of delivery, among 1,780,156 mother-infant pairs in a Medicaid Analytic eXtract pregnancy cohort, 2000–2013. Results were standardized to the population of mother-infant pairs with deliveries in 2000–2001, with stepwise adjustment for risk factors (age at delivery, race/ethnicity, smoking status, overweight/obesity, pregestational diabetes, pregestational hypertension), prenatal screening tests (first-trimester ultrasound, second-/third-trimester ultrasound, 3-dimensional ultrasound, fetal echocardiography), and postnatal cardiac imaging.

The trends were attenuated for severe or persistent cases of secundum ASD, PDA, and VSD after accounting for pre- and postnatal imaging. Extending the malformation assessment window to 1 year after birth led to similar trends, with a slight increase in the prevalence of secundum ASD and VSD (on the order of 1 per 1,000) but not of PDA (see Web Figure 1). The prevalence of heart murmurs increased from 32.4‰ in 2000 to 44.4‰ in 2013 (see Web Figure 2).

Web Figure 1.

Prevalence Trends per 1,000 Infants (With 95% Confidence Intervals) of A) Secundum Atrial Septal Defect, B) Patent Ductus Arteriosus, and C) Ventricular Septal Defect, per Year of Delivery, With Outcome Assessment 1) Within 3 Months After Birth (Full Cohort), 2) Within 1 Year After Birth (Subcohort)1, and 3) After 3 Months and Within 1 Year After Birth (Subcohort), Among 1,780,156 (Full Cohort) and 1,500,942 (Subcohort) Mother-Infant Pairs, Medicaid Analytic eXtract Pregnancy Cohort, 2000–2013.)
1We observe an increase in the prevalence of severe cases (especially secundum atrial septal defect and patent ductus arteriosus) when extending the assessment window to 1 year after birth since some cases with surgery after 3 months move from mild to severe cases in our classification.

Web Figure 2.

Prevalence Trends per 1,000 Infants (With 95% Confidence Intervals) of Heart Murmurs Based on ≥1 ICD-9-CM code 785.2 in the Infant Records During the First 3 Months After Birth or in the Maternal Records During the First Month After Birth, per Year of Delivery, Among 1,780,156 Mother-Infant Pairs, Medicaid Analytic eXtract Pregnancy Cohort, 2000–2013.

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