Validation of case definition algorithms for the ascertainment of congenital anomalies.

BACKGROUND: Congenital anomalies (CA) are one of the leading causes of infant mortality and long-term disability. Many jurisdictions rely on health administrative data to monitor these conditions. Case definition algorithms can be used to monitor CA; however, validation of these algorithms is needed to understand the strengths and limitations of the data. This study aimed to validate case definition algorithms used in a CA surveillance system in British Columbia (BC), Canada. METHODS: A cohort of births between March 2000 and April 2002 in BC was linked to the Health Status Registry (HSR) and the BC Congenital Anomalies Surveillance System (BCCASS) to identify cases and non-cases of specific anomalies within each surveillance system. Measures of algorithm performance were calculated for each CA using the HSR as the reference standard. Agreement between both databases was calculated using kappa coefficient. The modified Standards for Reporting Diagnostic Accuracy guidelines were used to enhance the quality of the study. RESULTS: Measures of algorithm performance varied by condition. Positive predictive value (PPV) ranged between approximately 73%-100%. Sensitivity was lower than PPV for most conditions. Internal congenital anomalies or conditions not easily identifiable at birth had the lowest sensitivity. Specificity and negative predictive value exceeded 99% for all algorithms. CONCLUSION: Case definition algorithms may be used to monitor CA at the population level. Accuracy of algorithms is higher for conditions that are easily identified at birth. Jurisdictions with similar administrative data may benefit from using validated case definitions for CA surveillance as this facilitates cross-jurisdictional comparison.

Cannabis use in pregnancy and maternal and infant outcomes: A Canadian cross-jurisdictional population-based cohort study.

BACKGROUND: With the recent legalization of cannabis in Canada, there is an urgent need to understand the effect of cannabis use in pregnancy. Our population-based study investigated the effects of prenatal cannabis use on maternal and newborn outcomes, and modification by infant sex. METHODS: The cohort included 1,280,447 singleton births from the British Columbia Perinatal Data Registry, the Better Outcomes Registry & Network Ontario, and the Perinatal Program Newfoundland Labrador from April 1st, 2012 to March 31st, 2019. Logistic regression determined the associations between prenatal cannabis use and low birth weight, small-for-gestational age, large-for-gestational age, spontaneous and medically indicated preterm birth, very preterm birth, stillbirth, major congenital anomalies, caesarean section, gestational diabetes and gestational hypertension. Models were adjusted for other substance use, socio-demographic and-economic characteristics, co-morbidities. Interaction terms were included to investigate modification by infant sex. RESULTS: The prevalence of cannabis use in our cohort was approximately 2%. Prenatal cannabis use is associated with increased risks of spontaneous and medically indicated preterm birth (1.80[1.68-1.93] and 1.94[1.77-2.12], respectively), very preterm birth (1.73[1.48-2.02]), low birth weight (1.90[1.79-2.03]), small-for-gestational age (1.21[1.16-1.27]) and large-for-gestational age (1.06[1.01-1.12]), any major congenital anomaly (1.71[1.49-1.97]), caesarean section (1.13[1.09-1.17]), and gestational diabetes (1.32[1.23-1.42]). No association was found for stillbirth or gestational hypertension. Only small-for-gestational age (p = 0.03) and spontaneous preterm birth (p = 0.04) showed evidence of modification by infant sex. CONCLUSIONS: Prenatal cannabis use increases the likelihood of preterm birth, low birth weight, small-for-gestational age and major congenital anomalies with prenatally exposed female infants showing evidence of increased susceptibility. Additional measures are needed to inform the public and providers of the inherent risks of cannabis exposure in pregnancy.

Travel Time to Delivery, Antenatal Care, and Birth Outcomes: A Population-Based Cohort of Uncomplicated Pregnancies in British Columbia, 2012-2019.

OBJECTIVE: Health policy and system leaders need to know whether long travel time to a delivery facility adversely affects birth outcomes. In this study, we estimated associations between travel time to delivery and outcomes in low-risk pregnancies. METHODS: This population-based cohort included all singleton births without obstetric comorbidities or intrapartum facility transfers in British Columbia, Canada, from 2012 to 2019. Travel time was measured from maternal residential postal code to delivery facility using road network analysis. We estimated associations between travel time and severe maternal morbidity, stillbirth, pre-term birth, and small-for-gestational age (SGA) and large-for-gestational age (LGA) status using logistic regression, adjusted for confounders (adjusted odds ratios [aORs]). To examine variations in associations between travel time and outcomes by antenatal care utilization, we stratified models by antenatal care categories. RESULTS: Of 232 698 births, 3.8% occurred at a facility ≥60 minutes from the maternal residence. Obesity, adolescent age, substance use, inadequate prenatal care, and low socioeconomic status were more frequent among those traveling farther for delivery. Travel time ≥120 minutes was associated with increased risk of stillbirth (aOR 1.8; 95% CI 1.2-2.8), pre-term birth (aOR 2.3; 95% CI 2.1-2.5), LGA (aOR 1.5; 95% CI 1.4-1.6), and severe maternal morbidity (aOR 1.5; 95% CI 1.2-1.8), but not SGA (aOR 1.0; 95% CI 0.8-1.1), when compared with a travel time of 1-29 minutes. Risk of stillbirth was greatest with inadequate and intensive (adequate plus) antenatal care but persisted for severe maternal morbidity, pre-term birth, and LGA across categories. CONCLUSION: Longer travel time to delivery was associated with increased risk of adverse outcomes in low-risk pregnancies after adjusting for confounding factors. Associations were stronger among those with inadequate antenatal care.