Embrology

Which of the following is assumed when using the first day of the last menstrual period for dating?

• The patient has a 36-day cycle.
• The patient became pregnant on that day
• The patient ovulated approximately two weeks later
• The first day of the last menstrual period was implantation bleeding.

What is the accuracy of an ultrasound measurement shown below?

• ±2-3 days
• ±5-7 days
• ± 8-10 days
• ±12-14 days

Approximately how long is each trimester of pregnancy?

• 12 weeks
• 13 weeks
• 14 weeks
• 15 weeks

When is a conceptus termed an embryo?

• Third week from the last menstrual period
• Fifth week from the last menstrual period
• Sixth week from the last menstrual period
• Twelfth week from the last menstrual period

A 20-year-old primigravida presents to your office to start prenatal care. She reports having an ultrasound performed last week at another facility. She shows you an ultrasound image which is provided below. Interested in science, the patient would like to know what is happening to the fetus at this gestational age. Which of the following statements would be incorrect?

• The fetus has fingers and toes.
• Skins and nails are developing.
• The eyes are moving, and there is blinking.
• The fetus is beginning to make spontaneous movements.

A 29-year-old multigravida presents at 15 weeks' gestation to establish prenatal care. The patient's first child had a neural-tube defect. The patient did not know she was pregnant until this week, so she asks you about starting folic acid as she was counseled in her last pregnancy that she needed a higher dose because of her first child's condition. Which of the following statements should be covered in your counseling?

• Starting folic acid is just as beneficial now as ever, so she should start today but at a dose of 8 mg per day
• The neural-tube does not close until 21 weeks' gestation, so she should start folic acid 4 mg daily within the next 1-2 weeks
• The neural-tube closes by 6 weeks' gestation, so she would have needed to start the folic acid before then for it to be efficacious
• Having a prior child with a neural-tube defect does not increase the risk of a neural-tube defect in this pregnancy, so she does not need to worry about that.

The diencephalon, pictured below, gives rise to what part of the brain?

• Thalami
• Medulla
• Midbrain
• Cerebral hemispheres

How does the oxygen content of the blood coming to the heart from the inferior vena cava compare to the oxygen content of the blood leaving the placenta?

• Equal
• Lower
• Higher
• Varies depending on fetal activity

After birth, the intraabdominal remnants of the umbilical vein become which of the following?

• Ligamentum teres
• Umbilical ligaments
• Ligamentum venosum
• Ligamentum vascularum

Which value defines anemia in the fetus?

• 0.2
• 0.25
• 0.3
• 0.4