Validation of birth certificate and maternal recall of events in labor and delivery with medical records in the Iowa health in pregnancy study

Table 4 Validity of birth certificate data compared to medical records in the Iowa health in pregnancy study

Variable	Sensitivity (%)	Specificity (%)	PPV (%)	NPV (%)	True Positives (N)	False Positives (N)	False Negatives (N)	True Negatives (N)	Kappa
Low birthweight	98.3%	98.7%	93.5%	99.7%	289	20	5	1515	0.95
Preterm birth	99.3%	99.9%	99.8%	99.7%	543	1	4	1395	0.99
Post-term birth	97.5%	100.0%	100.0%	99.6%	196	0	5	1194	0.99
Pregnancy weight gain	98.9%	6.2%	79.5%	49.1%	1536	397	17	26	0.08
Vaginal delivery	97.3%	97.9%	99.2%	93.0%	1383	11	39	516	0.94
Induced labor	46.3%	80.0%	18.3%	93.9%	386	41	266	1213	0.61

Low birthweight was defined as infant weighing < 2500 g at birth. Preterm and post-term birth were defined as gestational age < 37 and ≥ 41 weeks gestation, respectively. Pregnancy weight gain was defined as an increase in maternal weight from the start of pregnancy through delivery; dichotomized as “yes” or “no”. Mode of delivery options were “vaginal” or “caesarean”

ISSN: 1471-2393