Examining the Prevalence Rates of Preexisting Maternal Medical Conditions and Pregnancy Complications by Source: Evidence to Inform Maternal and Child Research

Abstract

Objectives We sought to examine whether there are systematic differences in ascertainment of preexisting maternal medical conditions and pregnancy complications from three common data sources used in epidemiologic research. Methods Diabetes mellitus, chronic hypertension, gestational diabetes mellitus (GDM), gestational hypertensive disorders (GHD), placental abruption and premature rupture of membranes (PROM) among 4821 pregnancies were identified via birth certificates, maternal self-report at approximately 4 months postpartum and by discharge codes from the Statewide Planning and Research Cooperative System (SPARCS), a mandatory New York State hospital reporting system. The kappa statistic (k) was estimated to ascertain beyond chance agreement of outcomes between birth certificates with either maternal self-report or SPARCS. Results GHD was under-ascertained on birth certificates (5.7 %) and more frequently indicated by maternal report (11 %) and discharge data (8.2 %). PROM was indicated more on birth certificates (7.4 %) than maternal report (4.5 %) or discharge data (5.7 %). Confirmation across data sources for some outcomes varied by maternal age, race/ethnicity, prenatal care utilization, preterm delivery, parity, mode of delivery, infant sex, use of infertility treatment and for multiple births. Agreement between maternal report and discharge data with birth certificates was generally poor (kappa < 0.4) to moderate (0.4 ≤ kappa < 0.75) but was excellent between discharge data and birth certificates for GDM among women who underwent infertility treatment (kappa = 0.79, 95 % CI 0.74, 0.85). Conclusions for Practice Prevalence and agreement of conditions varied across sources. Condition-specific variations in reporting should be considered when designing studies that investigate associations between preexisting maternal medical and pregnancy-related conditions with health outcomes over the life-course.

The role of obesity in the risk of gestational diabetes among immigrant and U.S.-born women in New York City

“…The validity of both GDM and obesity may vary somewhat by race/ethnicity. 21,23,24 If cases of obesity were misclassified mostly among immigrant women with gestational diabetes, it could make the reported partial PARs among those groups spuriously lower. However, given that our overall pattern of findings is similar to previous research, it is unlikely that misclassification alone could explain our findings.…”

“…5 This approach produces high sensitivity with few false positives. 20,21 . Cases were identified from hospital discharge diagnosis ICD-9 codes 648.8–648.84, and from the birth certificate check box indicating the presence of gestational diabetes during pregnancy.…”

Risks of preterm birth among non‐Hispanic black and non‐Hispanic white women: Effect modification by maternal age

“…All medical/obstetrical variables were categorical and included prenatal care (none, first, second or third trimester), pre‐pregnancy body mass index (BMI; underweight, normal weight, overweight, obese), rate of net gestational weight gain (inadequate, appropriate, excessive), diabetes (none, pre‐pregnancy, gestational), hypertensive disorders (none, chronic/pre‐pregnancy, or pregnancy‐associated), and asthma (yes/no). As previous studies have documented under‐reporting of maternal medical conditions on the birth certificate, ICD‐9 codes abstracted from the hospital billing records were used in conjunction with birth certificate data to define the hypertension, diabetes and asthma variables. Report of these conditions in either source was coded as the presence of the condition; cross‐tabulations for these variables are provided in Table .…”

Subsequent risk of stillbirth, preterm birth, and small for gestational age: A cross‐outcome analysis of adverse birth outcomes

“…All covariates were derived from vital records, except for chronic hypertension and pregestational diabetes, which were created from vital records and maternal discharge records. 29,30…”

“…Additionally, we provide unadjusted and adjusted risk differences with 95% CI confidence intervals for these associations. All covariates were derived from vital records, except for chronic hypertension and pregestational diabetes, which were created from vital records and maternal discharge records 29,30 …”