What is the most common type of fetal lie observed during pregnancy

Appeared in: KPSC Staff Nurse - 2015

Explanation

Fetal lie describes the relationship between the long axis of the fetus (spine) and the long axis of the mother.
The longitudinal or vertical lie, where the fetal and maternal spines are parallel, is the most common, occurring in over 99% of term pregnancies.
The ovoid shape of the uterus naturally accommodates the fetus in a longitudinal lie.
In a longitudinal lie, the presenting part can be either the head (cephalic presentation) or the buttocks/feet (breech presentation).

Option A: The oblique lie, where the fetal and maternal axes cross at a 45-degree angle, is rare and considered unstable because it typically converts to a longitudinal or transverse lie as labor progresses.
Option C: Shoulder is a type of fetal presentation, not a fetal lie. A shoulder presentation occurs when the fetus is in a transverse lie.
Option D: The transverse lie, where the fetal long axis is perpendicular to the maternal spine, is an abnormal and rare lie, complicating only about 0.3% of births.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Fetal lie and its types as background academic context rather than a clinical decision trigger.
Assessment of fetal lie is a fundamental component of Leopold's maneuvers, a standard antenatal examination performed by nurses and doctors to determine fetal position before delivery.
An abnormal lie (transverse or oblique) identified late in pregnancy is a critical finding. It requires close monitoring and planning for a potential Cesarean section to prevent complications like cord prolapse or obstructed labor.
What if? If a transverse lie is detected at 38 weeks gestation, the management plan would shift from awaiting spontaneous labor to considering an external cephalic version (ECV) or scheduling a planned Cesarean section to ensure a safe delivery.

How to Approach the Question

Identify the key term in the question: 'most common type of fetal lie'.
Recall the definition of fetal lie: the relationship of the fetus's long axis (spine) to the mother's long axis.
Consider the anatomical shape of the uterus. Its ovoid (egg-like) shape naturally encourages the fetus to align its longest dimension with the uterus's longest dimension.
This alignment is the longitudinal or vertical lie, making it the most common and stable position.
Evaluate the other options. Transverse and oblique lies are known to be unstable or abnormal and are therefore much less common.
Recognize that 'shoulder lie' is a distractor, as the shoulder is a presentation, not a lie.

Concept Tested & Keywords

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E6 Obstetrics Williams p. 19-36

Practise the full KPSC Staff Nurse - 2015

Attempt every question from this paper in a timed mock, then review the full solution for each one.