Peripartum Cardiomyopathy in the Obstetric Intensive Care Unit: Seasonal Associations and the Impact of Winter in the Kashmir Valley.

Background Peripartum cardiomyopathy (PPCM) is a form of idiopathic systolic heart failure that presents in late pregnancy or the early postpartum period in the absence of an identifiable etiology. Because its symptoms overlap with those of normal pregnancy, the diagnosis is frequently delayed or missed. Seasonal peaks in cardiovascular morbidity and mortality are well described in older, non-obstetric populations, but no previous study has examined this phenomenon in obstetric patients with PPCM. We aimed to determine whether the proportion of obstetric intensive care unit (ICU) admissions attributable to PPCM and its associated mortality are higher during winter than during the remaining seasons. Materials and methods This retrospective observational study included all obstetric patients admitted to the ICU of a tertiary-care referral center in the Kashmir Valley, North India, between January 1, 2018 and April 1, 2024. Medical records were reviewed to identify cases of new-onset PPCM; women with pre-existing cardiac disease were excluded. Admissions were stratified by season (spring: February 15 to May 15; summer: May 15 to August 15; autumn: August 15 to November 15; winter: November 15 to February 15). Groups were compared using the chi-square test, with odds ratios (OR) and 95% confidence intervals (CI). A p-value of less than 0.05 was considered significant. Results Of 1,899 obstetric ICU admissions, 166 (8.74%) received a new diagnosis of PPCM. Winter accounted for 88 of the 166 PPCM admissions (53.01%), compared with 78 (46.99%) for the other three seasons combined, whereas only 365 of 1,733 non-PPCM admissions (21.06%) occurred in winter. The odds that an obstetric ICU admission was attributable to PPCM were therefore more than four times higher in winter (OR 4.22, 95% CI 3.05-5.85; χ² = 85.14; p < 0.001). Fifteen patients with PPCM died in hospital, of whom 11 (73.33%) died during winter; the case fatality rate among patients with PPCM was 12.50% in winter compared with 5.13% in the other seasons. Hypertensive disorder of pregnancy was the commonest comorbidity (52.41%), and 43.98% of patients presented in New York Heart Association functional class IV. Conclusions A clinically and statistically significant seasonal association was observed regarding the proportion of PPCM admissions among obstetric ICU patients in the Kashmir Valley, with the greatest burden concentrated in winter; however, these findings may be confounded by delayed presentation due to winter transport difficulties.  Heightened surveillance, intensified antenatal follow-up, and a low threshold for echocardiography during the cold season are recommended, particularly for women referred from peripheral facilities.