HESI Maternity 55 Questions

Correct Answer: A

Rationale: The correct answer is A: monozygotic (MZ) twins. Monozygotic twins, also known as identical twins, occur when a single zygote splits into two embryos, leading to two genetically identical individuals. Choice B, fraternal twins, are twins that develop from two separate eggs fertilized by two different sperm cells, resulting in non-identical siblings. Choice C, non-identical twins, is not a common term used to describe this type of twinning. Choice D, dizygotic (DZ) twins, refer to twins that develop from two separate eggs fertilized by two different sperm cells, leading to non-identical twins.

Correct Answer: D

Rationale: The correct answer is D. The likelihood of having a child with Down's syndrome increases as the age of the parents increases, particularly the mother's age. Choice A is incorrect because Down's syndrome is caused by an extra copy of chromosome 21, not a defect in the sex chromosomes. Choice B is incorrect as the symptoms of Down's syndrome and sickle-cell anemia are different. Choice C is also incorrect as Down's syndrome is not caused by a sexually transmitted infection during conception.

Correct Answer: B

Rationale: Non-Hispanic White Americans have the lowest incidence of gestational diabetes mellitus (GDM) compared to other ethnicities. This is because GDM is more prevalent among certain ethnic groups, such as Asian, Hispanic, and African American populations. Asian individuals have an increased risk of developing GDM due to genetic factors, while Hispanic and African American populations have higher incidences of GDM due to lifestyle and genetic predispositions. Therefore, the correct answer is B, as Non-Hispanic White Americans generally have a lower risk of developing GDM.

Correct Answer: D

Rationale: Head and chest circumference measurements are within normal limits for a newborn, especially for those delivered by cesarean section, so no immediate action is required beyond documentation.

Correct Answer: B

Rationale: Women are born with approximately 300,000 to 400,000 ova, which gradually decrease in number as they age. Choice A ('close to 100,000 ova.') is incorrect as the actual number is much higher. Choice C ('around 100 to 200 ova.') is incorrect as it underestimates the quantity significantly. Choice D ('only 500 ova.') is incorrect as it greatly underestimates the number of ova present at birth.