Endocrinology of Pregnancy Practice Questions

Q: Up to what gestational age is the corpus luteum essential for pregnancy maintenance, such that its surgical excision would result in miscarriage?

8-10 weeks. ***8-10 weeks*** - The corpus luteum produces **progesterone** that is essential for maintaining early pregnancy until the **luteal-placental shift** occurs. - This shift, where the **placenta takes over progesterone production**, typically completes between **7-9 weeks** of gestation. - However, to ensure safety and account for individual variation, the corpus luteum should be considered essential **up to 10 weeks**. - Surgical excision of the corpus luteum **before 10 weeks** carries significant risk of miscarriage, while removal **after 10 weeks** is generally safe as the placenta has established autonomous progesterone production. *Before 6 weeks* - While removal before 6 weeks would certainly cause miscarriage, this is not the **maximum gestational age** at which the corpus luteum remains essential. - The critical dependency extends well beyond 6 weeks. *6-8 weeks* - During this period, the corpus luteum is still **absolutely essential** for progesterone production. - The luteal-placental shift is typically **incomplete** during this timeframe. - Removal would result in miscarriage, but this is still not the maximum safe window. *10-12 weeks* - By 10-12 weeks, the **placenta has fully taken over** progesterone production. - At this stage, the corpus luteum is no longer functionally necessary, and its removal does **not increase miscarriage risk**.

Q: Beta HCG is detected earliest by which day of conception?

8 days. ***Correct Option: 8 days*** - **Beta-hCG** is produced by the **syncytiotrophoblast** cells of the developing embryo immediately after implantation - Detectable in **maternal serum** as early as **8 days post-conception** (approximately 6-8 days post-implantation) - This corresponds to approximately 22-23 days after the last menstrual period (assuming a 28-day cycle with ovulation on day 14) - **Serum beta-hCG assays** are more sensitive than urine tests and allow for the earliest detection of pregnancy, even before a missed period - This early detection is clinically important for confirming early pregnancy, ectopic pregnancy diagnosis, and monitoring *Incorrect Option: 15 days* - While beta-hCG levels would be significantly higher and more reliably detected by 15 days post-conception, it is not the *earliest* day of detection - At this point, both serum and urine pregnancy tests would yield positive results - This timing is well past the point of initial detectability *Incorrect Option: 21 days* - By 21 days post-conception, beta-hCG levels are very high and pregnancy would be firmly established - This is much later than the earliest possible detection - This timing corresponds to approximately week 5 of gestation (calculated from LMP) *Incorrect Option: 30 days* - Detection at 30 days post-conception is very late for the initial detection of beta-hCG - By this point, pregnancy would be well-established with beta-hCG levels in thousands of mIU/mL - Other clinical signs and symptoms of pregnancy would likely be present

Q: Which acid-base derangement is seen in pregnancy?

Respiratory alkalosis. ***Respiratory alkalosis*** - During pregnancy, **progesterone** stimulates the respiratory drive, leading to an **increase in tidal volume and respiratory rate**. - This hyperventilation causes an excessive exhalation of **carbon dioxide (CO2)**, leading to a decrease in the partial pressure of CO2 (PaCO2) and a compensatory **respiratory alkalosis**. *Metabolic acidosis* - This condition occurs when there is an **excess of acid** or a **loss of bicarbonate** in the body. - It is not a typical physiological change in healthy pregnancies, although it can occur in conditions like **diabetic ketoacidosis** or **lactic acidosis**, which are not normal pregnancy states. *Metabolic alkalosis* - Metabolic alkalosis is characterized by an **increase in bicarbonate** or a **loss of hydrogen ions**. - This is not a normal physiological adaptation during pregnancy; instead, bicarbonate levels are often slightly decreased as a compensation for respiratory alkalosis. *Respiratory acidosis* - This state is caused by **hypoventilation**, leading to an **accumulation of CO2** in the blood. - Pregnancy typically involves **hyperventilation**, making respiratory acidosis an unlikely physiological occurrence.

Q: Overt diabetes in pregnancy is defined as fasting blood glucose greater than or equal to which of the following thresholds?

>126 mg/dl. **>126 mg/dl** - **Overt diabetes in pregnancy** (pre-existing diabetes detected during pregnancy) is diagnosed when fasting plasma glucose levels are **≥126 mg/dL**, or when HbA1c is **≥6.5%**, or when random plasma glucose is **≥200 mg/dL** with symptoms of hyperglycemia. - This threshold identifies individuals with pre-existing diabetes or severe hyperglycemia during pregnancy, requiring immediate management and distinction from gestational diabetes mellitus (GDM). *>200 mg/dl* - A random plasma glucose of **≥200 mg/dL** with symptoms is indicative of overt diabetes in pregnancy. - However, for a *fasting* blood glucose threshold for overt diabetes in pregnancy, **126 mg/dL** is the specific cutoff, not 200 mg/dL. *>100 mg/dl* - A fasting glucose of **100-125 mg/dL** in pregnancy falls in the impaired fasting glucose range. - For gestational diabetes mellitus (GDM), the fasting threshold is **≥92 mg/dL**, while for overt diabetes in pregnancy, it is **≥126 mg/dL**. *>180 mg/dl* - While **180 mg/dL** is a significant glucose level and represents the 1-hour OGTT cutoff for GDM, it doesn't align with the specific diagnostic criteria for *fasting* blood glucose in overt diabetes in pregnancy. - The fasting threshold for overt diabetes in pregnancy is **126 mg/dL**.

Q: Which of the following statements is correct regarding the functions of the placenta?

The placenta produces several hormones including estrogen.. ***The placenta produces several hormones including estrogen.*** - The placenta acts as a temporary **endocrine organ**, producing various hormones essential for maintaining pregnancy, including **estrogen**, **progesterone**, and **human chorionic gonadotropin (hCG)**. - **Estrogen** contributes to uterine growth, increased blood flow, breast development, and preparation for lactation. - Other placental hormones include **human placental lactogen (hPL)** and **relaxin**. *The placenta secretes insulin for fetal glucose regulation.* - This is **incorrect**. The placenta does NOT produce insulin. - **Insulin** is produced by the **fetal pancreas** (and maternal pancreas for the mother), not by the placenta. - The placenta facilitates glucose transfer but does not regulate it through insulin secretion. *The umbilical cord contains 2 arteries and 1 vein.* - While this statement is anatomically **correct** about umbilical cord structure, it describes the **umbilical cord anatomy**, not the **functions of the placenta**. - The question specifically asks about placental functions, not anatomical structures of associated components. *The placenta directly transfers maternal blood to the fetus.* - This is **incorrect**. Maternal and fetal blood do NOT mix directly. - The placenta maintains **separate circulatory systems** with exchange occurring across the **placental membrane** (barrier). - Nutrients, oxygen, and waste products are exchanged via **diffusion, active transport, and facilitated diffusion** across this barrier, not through direct blood transfer.

Q: Which hormone is primarily responsible for insulin resistance during pregnancy?

HPL. ***HPL*** - **Human placental lactogen (HPL)**, also known as **chorionic somatomammotropin**, directly induces maternal insulin resistance to ensure a continuous supply of glucose to the fetus. - HPL levels rise throughout pregnancy, peaking in the third trimester, correlating with increasing insulin resistance. *Estrogen* - While **estrogen** levels are high in pregnancy, its primary role is in supporting uterine growth and maintaining the pregnancy, not directly causing significant insulin resistance. - High estrogen levels can enhance insulin sensitivity in some contexts, contrasting with the overall insulin resistance of pregnancy. *Progesterone* - **Progesterone** is crucial for maintaining pregnancy and relaxing smooth muscle but does not directly cause the marked insulin resistance seen in gestation. - It works synergistically with other hormones but is not the primary driver of glucose intolerance in pregnancy. *GH* - **Growth hormone (GH)** does contribute to insulin resistance in non-pregnant individuals and at high levels can cause insulin resistance, but it is not the primary hormone responsible for the unique physiological insulin resistance of pregnancy. - While GH is present, **HPL** is the dominant somatotropic hormone of pregnancy directly impacting glucose metabolism.

Q: What is the primary maternal cause of fetal macrosomia (large birth weight) in newborns?

Hyperglycemia. ***Hyperglycemia*** - Maternal **hyperglycemia**, often due to **gestational diabetes**, leads to increased glucose transfer across the placenta to the fetus. - This excess glucose stimulates increased fetal insulin production, which acts as a growth hormone causing macrosomia. *Hyperinsulinemia* - While fetal **hyperinsulinemia** directly causes macrosomia by increasing fetal growth, it is a **consequence** of maternal hyperglycemia, not the primary cause itself. - Fetal insulin acts as an anabolic hormone, promoting fat and protein synthesis and overall growth. *Multiparity* - **Multiparity** (having given birth to multiple children) is generally associated with moderately higher birth weights, but it is not the primary cause of macrosomia. - The effect is far less significant and consistent than that of maternal hyperglycemia. *Post maturity* - **Post-term pregnancy** (post maturity) can sometimes be associated with a larger birth weight, but this is less common and less pronounced than macrosomia caused by hyperglycemia. - Fetal growth often slows or even declines in prolonged pregnancies due to placental insufficiency.

Q: The "cutoff" value of plasma glucose in a 50-g glucose challenge test is

140 mg/dL. ***140 mg/dL*** - A plasma glucose level of **140 mg/dL** (7.8 mmol/L) or higher one hour after a **50-g glucose challenge** is considered abnormal and warrants further investigation with a 3-hour oral glucose tolerance test (OGTT). - This cutoff helps identify individuals at risk for **gestational diabetes mellitus (GDM)**. *120 mg/dL* - This value is below the established cutoff for an abnormal 50-g glucose challenge test. - A plasma glucose level of 120 mg/dL one hour after glucose intake is generally considered within the **normal range** for this screening test. *160 mg/dL* - While 160 mg/dL is an elevated value, the standard cutoff used to indicate a positive screen is 140 mg/dL. - Using a higher cutoff like 160 mg/dL would **decrease the sensitivity** of the screening test, potentially missing cases of gestational diabetes. *180 mg/dL* - A plasma glucose level of 180 mg/dL is significantly elevated and would certainly lead to further testing. - However, the American College of Obstetricians and Gynecologists (ACOG) and other major organizations recommend the **140 mg/dL cutoff** for initial screening to maximize sensitivity.

Question 1

Up to what gestational age is the corpus luteum essential for pregnancy maintenance, such that its surgical excision would result in miscarriage?

Accepted Answer

8-10 weeks

Answer

Before 6 weeks

Answer

6-8 weeks

Answer

10-12 weeks

Question 2

Beta HCG is detected earliest by which day of conception?

Accepted Answer

8 days

Answer

15 days

Answer

21 days

Answer

30 days

Question 3

Which acid-base derangement is seen in pregnancy?

Accepted Answer

Respiratory alkalosis

Answer

Metabolic acidosis

Answer

Metabolic alkalosis

Answer

Respiratory acidosis

Question 4

Overt diabetes in pregnancy is defined as fasting blood glucose greater than or equal to which of the following thresholds?

Accepted Answer

>126 mg/dl

Answer

>200 mg/dl

Answer

>100 mg/dl

Answer

>180 mg/dl

Question 5

Which of the following statements is correct regarding the functions of the placenta?

Accepted Answer

The placenta produces several hormones including estrogen.

Answer

The placenta secretes insulin for fetal glucose regulation.

Answer

The umbilical cord contains 2 arteries and 1 vein.

Answer

The placenta directly transfers maternal blood to the fetus.

Question 6

Which hormone is primarily responsible for insulin resistance during pregnancy?

Accepted Answer

HPL

Answer

Estrogen

Answer

Progesterone

Answer

GH

Question 7

What is the most common fetal complication associated with gestational diabetes?

Accepted Answer

There is a risk of macrosomia in babies born to mothers with gestational diabetes.

Answer

Only a small percentage of women with gestational diabetes develop overt diabetes.

Answer

Gestational diabetes is usually diagnosed in the second or third trimester.

Answer

Gestational diabetes can increase the risk of congenital malformations.

Question 8

Which of the following statements about gestational diabetes mellitus (GDM) is true?

Accepted Answer

Gestational diabetes mellitus is first recognized during pregnancy.

Answer

It is always associated with a previous history of IUGR.

Answer

There is no recurrence of GDM in future pregnancies.

Answer

There is no risk of developing overt diabetes in the future.

Question 9

What is the primary maternal cause of fetal macrosomia (large birth weight) in newborns?

Accepted Answer

Hyperglycemia

Answer

Hyperinsulinemia

Answer

Multiparity

Answer

Post maturity

Question 10

The "cutoff" value of plasma glucose in a 50-g glucose challenge test is

Accepted Answer

140 mg/dL

Answer

120 mg/dL

Answer

160 mg/dL

Answer

180 mg/dL

Endocrinology of Pregnancy — MCQs

Endocrinology of Pregnancy — MCQs

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