Acute Hypotension Challenge

The day after dose responses, fetuses were exposed to an acute hypotension challenge (Figure S2). This consisted of 10 minutes of baseline, 10 minutes of hypotension, and 10 minutes of recovery. For chronic hypoxic pregnancies, the acute hypotension challenge occurred while inside the hypoxic chambers. For normoxic pregnancies, the acute hypotension challenge occurred while the animal was in a metabolic crate, inside a laboratory. Acute hypotension was induced via intravenous infusion of sodium nitroprusside (Sigma, United Kingdom, 50 μg/kg per minute). The dosing regimen of nitroprusside was adapted from past experiments in our laboratory, which achieved a significant reduction in arterial blood pressure that triggered compensatory cardiovascular responses.^20–22