CPM CPM Anatomy and Physiology for Midwifery 1 — Questions and Answers
Question 1: Which pelvic type is considered most favorable for vaginal birth?
- Android
- Platypelloid
- Gynecoid (Correct answer)
- Anthropoid
Correct answer: Gynecoid
The gynecoid pelvis has a rounded inlet, adequate outlet, and straight side walls, making it the most common type in women and most favorable for normal fetal descent.
Question 2: The ischial spines are used as a landmark for which clinical assessment in labor?
- Cervical dilation
- Fetal station (Correct answer)
- Rupture of membranes
- Pelvic inlet diameter
Correct answer: Fetal station
Fetal station is measured in centimeters above or below the ischial spines, with 0 station meaning the presenting part is level with the spines.
Question 3: Which ligament provides the primary support for the uterus and is often the source of round ligament pain during pregnancy?
- Broad ligament
- Uterosacral ligament
- Round ligament (Correct answer)
- Cardinal ligament
Correct answer: Round ligament
The round ligaments extend from the uterine cornu to the labia majora and stretch as the uterus enlarges, causing the sharp, stabbing round ligament pain common in mid-pregnancy.
Question 4: During pregnancy, which physiological change in blood volume is responsible for the dilutional anemia of pregnancy?
- Decrease in total blood volume
- Plasma volume increases more than red cell mass (Correct answer)
- Red cell mass decreases sharply
- Erythropoietin production falls
Correct answer: Plasma volume increases more than red cell mass
Plasma volume expands by approximately 40–50% while red cell mass increases only 20–30%, resulting in hemodilution and a lower hematocrit despite absolute increases in red cells.
Question 5: What is the primary function of the decidua basalis during pregnancy?
- Forms the fetal side of the placenta
- Forms the maternal side of the placenta and anchors it to the uterus (Correct answer)
- Secretes progesterone after 12 weeks
- Produces amniotic fluid
Correct answer: Forms the maternal side of the placenta and anchors it to the uterus
The decidua basalis is the portion of the maternal endometrium underlying the implantation site that forms the maternal component of the placenta and provides the anchorage zone.
Question 6: The diagonal conjugate is approximately how much longer than the true (obstetric) conjugate?
- 0.5 cm
- 1.0 cm
- 1.5 cm (Correct answer)
- 2.5 cm
Correct answer: 1.5 cm
The obstetric conjugate is estimated by subtracting 1.5 cm from the clinically measurable diagonal conjugate, which is palpated from the inferior pubic symphysis to the sacral promontory.
CPM CPM Anatomy and Physiology for Midwifery 1
Which pelvic type is considered most favorable for vaginal birth?