NM702 SECOND TRIMESTER EXAM QUESTIONS AND ANSWERS
WITH DETAILED VERIFIED SOLUTIONS
How would you determine an EDB and current gestational age for a patient who
presents for initial prenatal care in the second trimester?
Use the same history-taking approach used in the first trimester
What if the person was sure of their LMP?
• Negeles rule for sure LMP. determine whether LMP or ultrasound dating is the right
choice
What if they had no idea about LMP?
• If they are unsure about the LMP, then ultrasound is crucial and confirm the dates with
various events:
◦ Onset of pregnancy symptoms
◦ Date of any positive home pregnancy tests
◦ Date of quickening (first fetal movement the patient felt)
◦ Fundal height
Which fetal structures are used for dating ultrasounds in the second trimester?
• CRL = crown-rump length
• BPD = biparietal diameter
• HC = head circumference
• AC = abdominal circumference
• FL = femur length
Why are earlier-dating ultrasounds more accurate than later-dating ultrasounds?
, • Because all conceptuses begin at the same size, but fetal growth becomes more and
more variable as the pregnancy progresses
Imagine a patient is unhappy with the EDB you have set. How will you respond?
• Making a clinically erroneous due date change is not something that falls under shared
decision-making. Harm could result from using a less accurate EDB if complications
were to present later in pregnancy, necessitating interventions such as induction of
labor
Determine gestational age at <9 weeks
Measure CRL
change if there is more than 5 day difference
Determine gestational age at 9-13 weeks
Measure CRL
Change is more than 7 day difference
Determine GA at 14-15 weeks
Measure everything
Change is more than 7 day difference
Determine GA at 16-21 weeks
Measure everything
Change if more than 10 days difference
Determine GA at 22-27 weeks
Measure everything
Change is difference greater than 14 days
Determine GA at 28+ weeks
WITH DETAILED VERIFIED SOLUTIONS
How would you determine an EDB and current gestational age for a patient who
presents for initial prenatal care in the second trimester?
Use the same history-taking approach used in the first trimester
What if the person was sure of their LMP?
• Negeles rule for sure LMP. determine whether LMP or ultrasound dating is the right
choice
What if they had no idea about LMP?
• If they are unsure about the LMP, then ultrasound is crucial and confirm the dates with
various events:
◦ Onset of pregnancy symptoms
◦ Date of any positive home pregnancy tests
◦ Date of quickening (first fetal movement the patient felt)
◦ Fundal height
Which fetal structures are used for dating ultrasounds in the second trimester?
• CRL = crown-rump length
• BPD = biparietal diameter
• HC = head circumference
• AC = abdominal circumference
• FL = femur length
Why are earlier-dating ultrasounds more accurate than later-dating ultrasounds?
, • Because all conceptuses begin at the same size, but fetal growth becomes more and
more variable as the pregnancy progresses
Imagine a patient is unhappy with the EDB you have set. How will you respond?
• Making a clinically erroneous due date change is not something that falls under shared
decision-making. Harm could result from using a less accurate EDB if complications
were to present later in pregnancy, necessitating interventions such as induction of
labor
Determine gestational age at <9 weeks
Measure CRL
change if there is more than 5 day difference
Determine gestational age at 9-13 weeks
Measure CRL
Change is more than 7 day difference
Determine GA at 14-15 weeks
Measure everything
Change is more than 7 day difference
Determine GA at 16-21 weeks
Measure everything
Change if more than 10 days difference
Determine GA at 22-27 weeks
Measure everything
Change is difference greater than 14 days
Determine GA at 28+ weeks
