Abstract
Objective: To improve the
prediction of maternal end-organ injury or death using
routinely-collected variables from the pre-pregnancy and the early
pregnancy period.
Design: Population-based cohort study using linked
administrative health data.
Setting: Ontario, Canada, April 1, 2006 to March 31, 2014.
Sample: Women aged 18-60 years with a livebirth or stillbirth,
of which one birth was randomly selected per woman.
Methods and main outcome measures: We constructed a CPM 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 CPM included variables collected from 12 months
before estimated conception until 19 weeks’ gestation. We developed a
separate CPM 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 CPM
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 of this model would enable clinical
use.
Tweetable abstract: Clinical factors ascertained through a
medical history in early pregnancy can moderately predict severe
maternal morbidity.
Funding: This study was supported by funding from the Canadian
Institutes of Health Research (grant number 15139).
Keywords: Women’s health, Epidemiology, Obstetrics and
Gynaecology