A woman is admitted at 41-weeks gestation for fetal evaluation following a motor vehicle accident.

Comprehensive and Detailed Explanation From Exact Extract–Based NCC C-EFM References:

This tracing shows recurrent late decelerations, decreased variability, and subtle baseline shifts—findings that strongly correspond to uteroplacental insufficiency. In trauma cases, NCC emphasizes that placental abruption is the most common fetal complication, caused by shearing forces separating the placenta from the uterine wall.

Key physiologic points per NCC/AWHONN/Menihan:

Maternal blunt abdominal trauma frequently leads to partial or concealed abruption.

Abruption produces decreased uteroplacental blood flow, resulting in:

Late decelerations

Minimal/absent variability

Baseline shifts or instability

Cord accident (option A) typically produces variable decelerations, not late-pattern decelerations.

Fetal trauma (option B) is extremely rare and does not produce a consistent deceleration pattern.

Thus, the physiology most consistent with this tracing and mechanism of injury is placental abruption.