ACOG Practice Bulletin 226 Verified Exam Questions and Answers
Latest update 2026/2027
Question:
True or False: Pretest and post- test counseling are essential and must be a part of any screening
program.
Answer:
True
Question:
What is aneuploidy?
Answer:
Having one or more extra or missing chromosomes
Question:
How common are chromosomal abnormalities in live births?
Answer:
1/150 live births are affected with a chromosome abnormality
Question:
Name three factors that increase the chance for a chromosome abnormality
Answer:
1. Maternal Age
Question:
2. Previous pregnancy affected with a chromosome abnormality
3. Ultrasound abnormalities
Do ACOG practice guidelines dictate an exclusive course of treatment?
Answer:
No The information is designed to aid practitioners in making decisions about appropriate obstetric
and gynecologic care. Variations in practice may be warranted based on the needs of the individual
patient, resources, and limitations unique to the institution or type of practice.
Question:
What is the most common autosomal trisomy?
Answer:
Trisomy 21 (Down syndrome)
,Question:
What is the most common sex chromosome abnormality?
Answer:
47, XXY Klinefelter syndrome
Question:
How common is Klinefelter syndrome?
Answer:
1/500 males are affected or 1/1,000 births
Question:
What is the only viable monosomy?
Answer:
Turner syndrome (45, X)
Question:
What percentage of cases of Down syndrome are caused by non-disjunction?
Answer:
95%
Question:
What is the median survival of individuals affected with Down syndrome in economically developed
countries?
Answer:
Approximately 60 years of age
Question:
What percentage of pregnancies affected with Down syndrome end in miscarriage or stillbirth?
Answer:
43%
Question:
Does ACOG discourage women who have a negative screening test for aneuploidy from having a
procedure such as amnio or CVS so that diagnostic testing such as microarray or chromosome analysis
can be performed
Answer:
No, even if a woman has had negative aneuploidy screening ACOG supports the option of diagnostic
testing should that patient want it
, Question:
Who does ACOG recommend should be offered the option of diagnostic testing as well as aneuploidy
screening and when?
Answer:
All women regardless of their age should be offered screening and diagnostic testing early in
pregnancy
Question:
What percentage of pregnancies affected with Down syndrome occur in women 35 or older at the time
of delivery?
Answer:
Approximately 22% (21.6%)
Question:
What is nondisjunction?
Answer:
Nondisjunction is the failure of homologous chromosomes or sister chromatids to separate subsequent
to metaphase in meiosis or mitosis so that one daughter cell has both and the other neither of the
chromosomes.
Question:
When a positive or abnormal screening test result occurs the patient should be counseled regarding the
adjusted likelihood or probability of carrying a fetus with the aneuploidy the pregnancy is at an
increased chance for.
Answer:
True
Question:
When a negative screening test result is obtained (low risk), the patient should simply be told that they
are at a low chance to have a fetus affected with a chromosome abnormality.
Answer:
False. It is recommended that patient's with both high and low risk results be given the probability for
aneuploidy if it can be estimated.
Question:
Name one thing that should be discussed regarding the limitations of aneuploidy screening.
Answer:
The potential for the fetus to be affected by a genetic disorder or abnormality that is not evaluated by
the screening or diagnostic tests being offered.
Latest update 2026/2027
Question:
True or False: Pretest and post- test counseling are essential and must be a part of any screening
program.
Answer:
True
Question:
What is aneuploidy?
Answer:
Having one or more extra or missing chromosomes
Question:
How common are chromosomal abnormalities in live births?
Answer:
1/150 live births are affected with a chromosome abnormality
Question:
Name three factors that increase the chance for a chromosome abnormality
Answer:
1. Maternal Age
Question:
2. Previous pregnancy affected with a chromosome abnormality
3. Ultrasound abnormalities
Do ACOG practice guidelines dictate an exclusive course of treatment?
Answer:
No The information is designed to aid practitioners in making decisions about appropriate obstetric
and gynecologic care. Variations in practice may be warranted based on the needs of the individual
patient, resources, and limitations unique to the institution or type of practice.
Question:
What is the most common autosomal trisomy?
Answer:
Trisomy 21 (Down syndrome)
,Question:
What is the most common sex chromosome abnormality?
Answer:
47, XXY Klinefelter syndrome
Question:
How common is Klinefelter syndrome?
Answer:
1/500 males are affected or 1/1,000 births
Question:
What is the only viable monosomy?
Answer:
Turner syndrome (45, X)
Question:
What percentage of cases of Down syndrome are caused by non-disjunction?
Answer:
95%
Question:
What is the median survival of individuals affected with Down syndrome in economically developed
countries?
Answer:
Approximately 60 years of age
Question:
What percentage of pregnancies affected with Down syndrome end in miscarriage or stillbirth?
Answer:
43%
Question:
Does ACOG discourage women who have a negative screening test for aneuploidy from having a
procedure such as amnio or CVS so that diagnostic testing such as microarray or chromosome analysis
can be performed
Answer:
No, even if a woman has had negative aneuploidy screening ACOG supports the option of diagnostic
testing should that patient want it
, Question:
Who does ACOG recommend should be offered the option of diagnostic testing as well as aneuploidy
screening and when?
Answer:
All women regardless of their age should be offered screening and diagnostic testing early in
pregnancy
Question:
What percentage of pregnancies affected with Down syndrome occur in women 35 or older at the time
of delivery?
Answer:
Approximately 22% (21.6%)
Question:
What is nondisjunction?
Answer:
Nondisjunction is the failure of homologous chromosomes or sister chromatids to separate subsequent
to metaphase in meiosis or mitosis so that one daughter cell has both and the other neither of the
chromosomes.
Question:
When a positive or abnormal screening test result occurs the patient should be counseled regarding the
adjusted likelihood or probability of carrying a fetus with the aneuploidy the pregnancy is at an
increased chance for.
Answer:
True
Question:
When a negative screening test result is obtained (low risk), the patient should simply be told that they
are at a low chance to have a fetus affected with a chromosome abnormality.
Answer:
False. It is recommended that patient's with both high and low risk results be given the probability for
aneuploidy if it can be estimated.
Question:
Name one thing that should be discussed regarding the limitations of aneuploidy screening.
Answer:
The potential for the fetus to be affected by a genetic disorder or abnormality that is not evaluated by
the screening or diagnostic tests being offered.
