Fetal Lie Description
The best description of fetal lie in this case is longitudinal (option c). 1
Understanding Fetal Lie vs. Presentation
Fetal lie refers specifically to the relationship between the long axis of the fetus and the long axis of the mother. This is distinct from fetal presentation, which describes the fetal part that is lowest in the pelvis. 1
Key Clinical Findings in This Case
The ultrasound demonstrates:
- Fetal spine parallel to mother's spine - this is the defining feature of longitudinal lie 1
- Fetal head in the fundus (indicating breech presentation, not vertex)
- Flexed knees, hips, and elbows
Why Longitudinal is Correct
- When the fetal spine runs parallel to the maternal spine, the lie is longitudinal by definition 1
- This occurs in approximately 99% of term pregnancies 1
- Longitudinal lie can occur with either cephalic (vertex) or breech presentations 1
Why the Other Options are Incorrect
Options a, b, and e (Incomplete breech, Frank breech, Complete breech):
- These describe fetal presentation, not fetal lie 2
- Frank breech: hips flexed, knees extended
- Complete breech: hips and knees both flexed (as in this case)
- Incomplete breech: one or both hips not fully flexed
- While this patient has a complete breech presentation based on the flexed hips and knees, the question specifically asks about fetal lie 2
Option d (Vertex):
- This describes cephalic presentation where the head is down 1
- This patient has the head in the fundus, ruling out vertex presentation 1
Clinical Significance
- The longitudinal lie with complete breech presentation in this patient without prenatal care requires immediate delivery planning 3
- Cesarean delivery is the most common approach for breech presentation, though vaginal breech delivery may be considered only with appropriate expertise and no contraindications 3
- The bulging membrane at 4 cm dilation indicates active labor is progressing 4