Validation of Obstetric Diagnosis and Procedure Codes in the Danish National Patient Registry in 2017.

Purpose: This study aimed to systematically evaluate the validity of variables related to pregnancy, delivery, and key characteristics of the infant in the Danish National Patient Register using maternal medical records as the reference standard. Patients and Methods: We reviewed medical records of 1264 women giving birth in the Region of Southern Denmark during 2017. We calculated positive (PPV) and negative (NPV) predictive values, sensitivity, and specificity to estimate the validity of 49 selected variables. Results: The PPV was ≥0.90 on most pregnancy-related variables including parity, pre-gestational BMI, diabetes disorders, and previous cesarean section, while it was lower for hypertensive disorders, especially mild to moderate preeclampsia (0.49, 95% CI 0.32-0.66). Sensitivity ranged from 0.80 to 1.00 on all pregnancy-related variables, except hypertensive disorders (sensitivity 0.38-0.71, lowest for severe preeclampsia). On most delivery-related variables including obstetric surgical procedures (eg cesarean section and induction of labor), pharmacological pain-relief, and gestational age at delivery, PPV's ranged from 0.98 to 1.00 and the corresponding sensitivities from 0.87 to 1.00. Regarding infant-related variables, both the APGAR score registered five minutes after delivery and birthweight yielded a PPV of 1.00. Conclusion: Obstetric coding in the Danish National Patient Register shows very high validity and completeness making it a valuable source for epidemiologic research.

The Impact of Maternal and Perinatal Factors on the Neonatal Electrocardiogram.

INTRODUCTION: Myocardial development is still transitioning by the time of birth making the cardiomyocyte vulnerable to maternal and perinatal factors. We aimed at investigating the impact of maternal and perinatal factors on the neonatal electrocardiogram. METHODS: In a prospective cohort study, neonates underwent cardiac evaluation with electrocardiograms and echocardiograms (age 0-30 days). Associations between medical and demographic data, pregnancy, and birth-related factors, and electrocardiographic parameters were assessed. RESULTS: A total of 15,928 singletons with normal echocardiograms were included (52% boys). Neonates were divided into groups by accumulated number of maternal/perinatal factors: 0, 1, 2, 3, 4, and ≥5, and between-group differences in electrocardiographic parameters were analysed. We observed an additive effect with a leftward shift of the QRS axis and QT prolongation (all p < 0.01). Comparing extreme groups (0 vs. ≥5 maternal/perinatal factors), we found a 4.3% more left-shifted QRS axis (117 vs. 112°, p < 0.001) and a 0.8% prolonged QTcFridericia (QTcF; 363 vs. 366 ms, p < 0.001); the effect on QTcF was most pronounced in neonates examined in the first week of life (360 vs. 368 ms, p < 0.0001). CONCLUSION: We observed a cumulative effect of maternal and perinatal factors on neonatal electrocardiographic parameters, including a more left-shifted QRS axis and increased QT duration, although the variation was within normal reference ranges. Our findings add to the knowledge on the neonatal cardiac transition and the cardiac effect of maternal/perinatal factors.