Development and internal validation of a model predicting severe maternal morbidity using pre-conception and early pregnancy variables: a population-based study in Ontario, Canada

Abstract

Background Improvement in the prediction and prevention of severe maternal morbidity (SMM) - a range of life-threatening conditions during pregnancy, at delivery or within 42 days postpartum - is a public health priority. Reduction of SMM at a population level would be facilitated by early identification and prediction. We sought to develop and internally validate a model to predict maternal end-organ injury or death using variables routinely collected during pre-pregnancy and the early pregnancy period. Methods We performed a population-based cohort study using linked administrative health data in Ontario, Canada, from April 1, 2006 to March 31, 2014. We included women aged 18–60 years with a livebirth or stillbirth, of which one birth was randomly selected per woman. We constructed a clinical prediction model for the primary composite outcome of any maternal end-organ injury or death, arising between 20 weeks’ gestation and 42 days after the birth hospital discharge date. Our model included variables collected from 12 months before estimated conception until 19 weeks’ gestation. We developed a separate model for parous women to allow for the inclusion of factors from previous pregnancy(ies). Results Of 634,290 women, 1969 experienced the primary composite outcome (3.1 per 1000). Predictive factors in the main model included maternal world region of origin, chronic medical conditions, parity, and obstetrical/perinatal issues – with moderate model discrimination (C-statistic 0.68, 95% CI 0.66–0.69). Among 333,435 parous women, the C-statistic was 0.71 (0.69–0.73) in the model using variables from the current (index) pregnancy as well as pre-pregnancy predictors and variables from any previous pregnancy. Conclusions A combination of factors ascertained early in pregnancy through a basic medical history help to identify women at risk for severe morbidity, who may benefit from targeted preventive and surveillance strategies including appropriate specialty-based antenatal care pathways. Further refinement and external validation of this model are warranted and can support evidence-based improvements in clinical practice.

Prepregnancy Emergency Department Use and Risks of Severe Maternal and Neonatal Morbidity in Canada

“…Although less prevalent, prepregnancy ED visits for a hematological, endocrine, or circulatory condition was associated with the highest RR of SMM (Table 4). Prepregnancy anemia, diabetes, and chronic hypertension have congruently been shown to be associated with SMM, stillbirth, and neonatal mortality in large cohort studies. ED visits for mental health diagnoses were prevalent and, similar to other studies, were associated with a higher risk of serious adverse maternal and perinatal outcomes.…”

Association between Cardiorespiratory Fitness and Hypertensive Disorders of Pregnancy: A Systematic Review and Meta-Analysis

“…The American Heart Association has recommended that CRF be used as a risk marker for morbidity and mortality in the general population [ 12 ], and our review suggests that CRF may be particularly valuable as a clinical vital sign in the peripartum period and during reproductive years. CRF may also prove useful in clinical prediction of maternal morbidity, as adverse cardiovascular outcomes make up a substantial proportion of severe maternal morbidity [ 37 , 38 ]. Finally, our findings suggest that dedicated postpartum cardiovascular rehabilitation after HDP may be worthwhile, using a patient-centred approach sensitive to the needs of new mothers.…”

Predictores de muerte materna en pacientes gestantes

“…Tasa de mortalidad materna: es el número de muertes maternas durante un período determinado por cada 100.000 nacidos vivos durante el mismo período. Este es un indicador de uso más común del riesgo de que una mujer muera a causa de un embarazo determinado o de su riesgo obstétrico 6 .…”