A persistent headache (HA) refractory to medication is a disease-defining characteristic of preeclampsia (PreE) with severe features (SF), requiring delivery regardless of GA. Features of high-grade maternal vascular malperfusion (HG-MVM) on preterm placental pathology are frequently associated with the PreE process, while their absence may suggest an alternate etiology. We sought to assess the frequency of HG-MVM in cases delivered < 34 weeks for a persistent HA associated with PreE, and correlate objective maternal, fetal, and placental values with HG-MVM.

All placental pathology reports in 2021-2022 at our tertiary center were reviewed for an indication of PreE, and 52 cases were confirmed. Maternal demographic, clinical, fetal, and placental objective measures were compiled. A pathologist analyzed specimens for evidence of lesions consistent with MVM. A score of low or high grade MVM was assigned based on lesion subtype frequency from a previously published scale. Chi-square, point-biserial correlations, and logistic regression were applied, with significance set at p< 0.05.

HG-MVM was found in only 23/52 (44.2%) of cases. Significant correlations included an SGA placenta (OR=13.5) and nephrotic range proteinuria (OR=12.3), with strong correlations for fetal (r=-.71) and placenta weights (r=-.75), and moderate correlations for fetal: placental weight (r=.32) and protein: creatinine ratio (r=.32). Logistic regression of significant continuous values accurately predicted the presence (91.3%) and absence (89.7%) of HG- MVM (p< 0.001). Near uniformly normal maternal serum values in our data limited their predictive utility. HG-MVM placentas showed higher prevalence of lesions indicative of aging as opposed to abnormal early placentation.

Placental dysfunction with HG-MVM was absent in 55.8% of cases in our study, suggesting that most persistent headaches prompting delivery were due to an etiology other than PreE with SF (i.e., migraines). HG-MVM is more likely when objective clinical findings consistent with PreE are seen (small fetal/placental size, objective maternal lab derangements) and less likely when absent. This information is useful in considering additional workup or pursuing delivery for a refractory headache with known or suspected PreE.