Evaluating the effect of maternal health conditions on severe maternal morbidity adjusting for emergent cesarean delivery: A mediation analysis approach

Moshe Fridman, Naomi H. Greene, Lisa M. Korst, Elizabeth Lawton, Samia El Haj Ibrahim, Flojaune Griffin, Lisa Nicholas, Kimberly D. Gregory
2016 Journal of Epidemiological Research  
The prevalence of pre-existing and gestational maternal health conditions is rising; affected women are at increased risk for both cesarean delivery (CD) and severe maternal morbidity (SMM). We estimated the increased risk of SMM associated with key maternal health conditions, and determined the extent to which it was directly associated with these conditions versus indirectly associated because of an increased risk of CD. Nulliparous, term, singleton, vertex (NTSV) gestations were identified
more » ... ong laboring women in California 2008-2010 hospital discharge datasets. Logistic regression models (stratified by younger vs. older women [≥ 35 years]) were constructed for each condition: chronic/gestational diabetes mellitus (DM), chronic/gestational hypertension, obesity, heart disease, and mental health diagnoses. Using mediation analysis, the potential effect associated with each condition (exposure) on SMM (outcome) consisted of a direct effect and an indirect effect caused by modification of the risk of an emergent CD (mediator). Of 502,654 deliveries, 24.3% had an emergent CD; 1.7% had SMM, which was present in 1.6% of younger vs. 2.2% of older mothers. The modeled odds ratios (ORs) for the direct effect on SMM were 2.00-2.67 for any hypertension, 0.78 for obesity in younger women, 6.57-7.97 for heart disease, and 1.43-1.58 for mental health diagnoses. No direct effect was identified for DM or obesity in older women. The ORs for the indirect effect were low, ranging from 0.94-1.11 for all models. For women laboring with NTSV gestations where key maternal health conditions were present, the risk of SMM mediated by an emergent CD was low, relative to the direct risk.
doi:10.5430/jer.v2n2p36 fatcat:rhpvsmudlneb3iaetco7gvt3qe