GLOSSARY

Luteal–Placental Shift
The luteal–placental shift is a gradual transfer of major progesterone support from corpus luteum to placenta.

Maternal, placental and fetal integration. Pregnancy changes hormone production, binding, clearance and target-tissue responsiveness. Maternal, placental and fetal tissues contribute different components. Expected laboratory patterns therefore depend on gestational stage and the analytical method, rather than nonpregnant reference values alone.

Interpreting the mechanism. Timing varies rather than occurring as one instantaneous switch.

Transitions around birth. Placental delivery rapidly changes steroid exposure, while prolactin-related synthesis and oxytocin-mediated ejection support lactation. These are coordinated but distinct mechanisms. Clinical problems during pregnancy or postpartum require interpretation within their specific maternal and fetal context.