Antepartum Care and Fetal Surveillance
A patient presents in labor at term. Clinical pelvimetry is performed. She has an oval-shaped pelvis with the anteroposterior (AP) diameter at the pelvic inlet greater than the transverse diameter. The baby is occiput posterior. The patient most likely has what kind of pelvis?
The answer is c. By tradition, pelves are classified as belonging to one of four major groups, based on the shape of the pelvis. A line drawn through the greatest diameter of the pelvic inlet divides the pelvis into anterior and posterior sections, and the shape of these segments helps determine the pelvis type. The gynecoid pelvis is the classic female pelvis, with a posterior sagittal diameter of the inlet only slightly shorter than the anterior sagittal diameter. The posterior pelvis is rounded and wide, the sidewalls are straight, the spines are not prominent, and the pubic arch is wide. In the android pelvis, the posterior sagittal diameter at the inlet is much shorter than the anterior sagittal diameter, limiting the use of the posterior space by the fetal head. The sidewalls are convergent, the spines are prominent, and the pubic arch is narrowed. In the anthropoid pelvis, the AP diameter of the inlet is greater than the transverse diameter, resulting in an oval with large sacrosciatic notches, convergent side walls, prominent ischial spines, and a narrow pubic arch. The platypelloid pelvis is flattened with a short AP and wide transverse diameter. Wide sacrosciatic notches are common. The pelves of most women do not fall into a pure type and are blends of one or more of these types.
Pelvic examination is performed in a 34-year-old P0101 at 34 weeks' gestation who is in labor. The patient is noted to be 6 cm dilated, and completely effaced with the fetal nose and mouth palpable. The chin is pointing toward the maternal left hip. This is an example of which of the following?
b. Mentum transverse position
c. Occiput transverse position
The answer is b. The lie of the fetus refers to the relation of the long axis of the fetus to that of the mother, and is classified as longitudinal, transverse, or oblique. The presentation, or presenting part, refers to the portion of the ...