A 40-year-old pregnant patient, currently hospitalized for preterm labor at 34 weeks’ gestation, is discussing potential delivery options with her provider based on the results of a fetal lung maturity test.

 Which prenatal test would the provider likely order to check for fetal lung maturity? 

Choice A rationale:

Incorrect. The Human Genome Project revealed that humans have approximately 20,000-25,000 genes, not 1,000. This finding significantly expanded our understanding of the complexity of the human genome.

Choice B rationale:

Incorrect. The concept of one gene producing three proteins is not a discovery from the Human Genome Project. While some genes can produce multiple protein isoforms through alternative splicing, this is not a universal feature of human genes.

Choice C rationale:

Correct. This is a major finding from the Human Genome Project. It highlights that despite our apparent differences, humans share a remarkably high degree of genetic similarity. This finding has implications for understanding human evolution, disease susceptibility, and pharmacogenomics.

Key points:

The vast majority of our DNA is shared among all humans.

The small percentage of genetic variation accounts for individual differences and diversity.

This finding challenges previous notions of race and ethnicity based on genetic differences.

It emphasizes the common origins and shared heritage of all humans.

Choice D rationale:

Incorrect. While single gene testing has become more common for certain genetic disorders, it is unlikely to become a standardized test for all patients in the future. This is due to the complexity of human genetics and the diverse factors that contribute to health and disease.

Choice A rationale:

Fetal position during the first trimester is not definitively determined through ultrasound. While the gestational sac and fetal pole can be visualized, the fetus is still quite small and has ample space to move within the amniotic sac. This makes it challenging to accurately ascertain its position.

Reliable assessment of fetal position typically occurs later in pregnancy, usually between 34 and 36 weeks gestation. At this point, the fetus is larger and less mobile, allowing for a clearer assessment of its position through ultrasound.

The early determination of fetal position in the first trimester is not a primary goal of ultrasound. It is more focused on establishing pregnancy viability, gestational age, and detecting any potential abnormalities.

Choice B rationale:

Ultrasound in the first trimester can reliably detect multiple gestations. It can visualize the presence of multiple gestational sacs or fetal poles, clearly indicating whether a woman is carrying twins, triplets, or more.

Early identification of multiple gestations is crucial for optimal pregnancy management. It allows healthcare providers to tailor prenatal care, monitor for potential complications associated with multiple pregnancies, and plan for appropriate delivery. Choice C rationale:

Ultrasound in the first trimester can assist in detecting certain maternal abnormalities that could impact pregnancy. These may include:

Uterine abnormalities, such as fibroids or structural defects

Ovarian cysts

Ectopic pregnancies (where the embryo implants outside the uterus)

Gestational trophoblastic disease (abnormal growth of tissue inside the uterus)

Early identification of these maternal abnormalities allows for timely intervention and management, ensuring the best possible outcomes for both mother and fetus.

Choice D rationale:

Confirming pregnancy is a primary reason for ultrasound in the first trimester. It can visualize the gestational sac, which contains the developing embryo and confirms the presence of a pregnancy.

Ultrasound can also detect the fetal heartbeat, which typically becomes visible between 6 and 8 weeks gestation. This provides further confirmation of a viable pregnancy.