Relationships between endogenous CYP3A markers and plasma amlodipine exposure and metabolism in early postpartum and non-peripartum women with hypertension.

•Early postpartum women had higher plasma 4β-OHC and lower plasma 25-OHD.•Early postpartum women had lower plasma exposure and higher metabolism of amlodipine.•CYP3A activity induced by pregnancy gradually declined after delivery.•Plasma amlodipine exposure and metabolism correlated with plasma 4β-OHC.•Plasma 25-OHD did not correlate with plasma amlodipine exposure in postpartum women.