Dosing in pregnancy and lactation MCQs With Answer

Dosing in pregnancy and lactation MCQs With Answer

Introduction: Pregnancy and lactation substantially alter drug pharmacokinetics—absorption, distribution, metabolism and excretion—requiring careful dosing and monitoring. For M.Pharm students, understanding trimester-specific physiologic changes, placental transfer mechanisms, milk/plasma ratio, relative infant dose (RID) calculations, and safety profiles of commonly used therapeutic classes is essential. This quiz collection focuses on clinically relevant principles and examples, integrating therapeutic drug monitoring (TDM) considerations, maternal-fetal risks, and lactation safety to support evidence-based dosing decisions. Questions emphasize mechanisms, numeric concepts, and practical management strategies to prepare students for both academic evaluation and real-world patient care in obstetric and neonatal pharmacotherapy.

Q1. Which physiological change in pregnancy most directly increases the apparent volume of distribution for hydrophilic drugs?

• Increase in plasma albumin concentration
• Decrease in total body water
• Increase in total body water and extracellular fluid
• Decrease in cardiac output

Correct Answer: Increase in total body water and extracellular fluid

Q2. How does decreased maternal albumin concentration in late pregnancy primarily affect highly protein-bound drugs?

• Decrease in free (unbound) fraction and decreased clearance
• Increase in free (unbound) fraction leading to increased pharmacologic effect
• No change in free fraction but increased half-life
• Increased protein binding to alpha-1-acid glycoprotein compensates

Correct Answer: Increase in free (unbound) fraction leading to increased pharmacologic effect

Q3. Which placental transfer mechanism is most important for small lipophilic drugs with low ionization?

• Carrier-mediated active transport
• Facilitated diffusion
• Simple passive diffusion
• Endocytosis by placental trophoblasts

Correct Answer: Simple passive diffusion

Q4. Relative infant dose (RID) is best described as:

• The ratio of infant plasma concentration to maternal plasma concentration
• The percentage of the maternal weight-adjusted dose received by the infant via milk
• The ratio of milk concentration to infant serum concentration
• The absolute amount of drug secreted in milk per day

Correct Answer: The percentage of the maternal weight-adjusted dose received by the infant via milk

Q5. A drug has a milk/plasma ratio of 1.5 but a high protein binding in maternal plasma. What is the most reliable next step to estimate infant exposure?

• Assume high infant exposure because milk/plasma >1
• Calculate RID using maternal dose, milk concentration, and infant weight
• Rely solely on milk/plasma ratio without further calculation
• Discontinue breastfeeding immediately

Correct Answer: Calculate RID using maternal dose, milk concentration, and infant weight

Q6. Which of the following antihypertensive drugs is contraindicated in pregnancy due to teratogenicity?

• Labetalol
• Methyldopa
• Angiotensin-converting enzyme (ACE) inhibitors
• Nifedipine

Correct Answer: Angiotensin-converting enzyme (ACE) inhibitors

Q7. During pregnancy, renal plasma flow and glomerular filtration rate (GFR) typically change how, and how does this affect elimination of renally cleared drugs?

• GFR decreases, reducing elimination of renally cleared drugs
• GFR increases, increasing clearance of renally cleared drugs
• GFR is unchanged, so elimination is unaffected
• GFR fluctuates randomly with no predictable impact

Correct Answer: GFR increases, increasing clearance of renally cleared drugs

Q8. Why is therapeutic drug monitoring (TDM) particularly important for antiepileptic drugs during pregnancy?

• Pregnancy reduces seizure threshold so TDM is unnecessary
• Physiological changes alter drug clearance and protein binding leading to variable free concentrations
• Antiepileptics are not transferred across the placenta, so TDM focuses on toxicity only
• TDM is replaced by routine ultrasound monitoring

Correct Answer: Physiological changes alter drug clearance and protein binding leading to variable free concentrations

Q9. Which antiseizure medication has the highest teratogenic risk, notably neural tube defects, and often necessitates risk-benefit counseling?

• Lamotrigine
• Carbamazepine
• Valproate (valproic acid)
• Levetiracetam

Correct Answer: Valproate (valproic acid)

Q10. Which antibiotic class is generally considered safe in pregnancy and often recommended for many infections due to favorable pharmacokinetics and safety?

• Tetracyclines
• Fluoroquinolones
• Beta-lactams (penicillins and cephalosporins)
• Aminoglycosides

Correct Answer: Beta-lactams (penicillins and cephalosporins)

Q11. What is the principal reason warfarin is avoided in pregnancy while low molecular weight heparin (LMWH) is preferred?

• Warfarin increases maternal blood pressure significantly
• Warfarin crosses the placenta and is teratogenic; LMWH does not cross placenta appreciably
• LMWH is less effective for anticoagulation in pregnancy
• Warfarin causes hyperglycemia in the fetus

Correct Answer: Warfarin crosses the placenta and is teratogenic; LMWH does not cross placenta appreciably

Q12. Which statement about CYP enzyme activity during pregnancy is most accurate?

• CYP3A4 activity generally decreases in pregnancy
• CYP1A2 activity is increased leading to lower concentrations of substrates
• CYP2D6 activity is inducible and often increases during pregnancy
• All CYP enzymes are uniformly suppressed during pregnancy

Correct Answer: CYP2D6 activity is inducible and often increases during pregnancy

Q13. A breastfeeding mother is on codeine. What genetic factor can increase risk of opioid toxicity in the infant?

• Poor CYP3A4 metabolizer phenotype
• Ultrarapid CYP2D6 metabolizer phenotype in the mother leading to high morphine levels in milk
• High UGT1A1 activity in the infant
• Maternal slow renal clearance of glucuronides

Correct Answer: Ultrarapid CYP2D6 metabolizer phenotype in the mother leading to high morphine levels in milk

Q14. When calculating Relative Infant Dose (RID), which RID percentage is generally considered acceptable/safe for most drugs during breastfeeding?

• RID < 10%
• RID > 50%
• RID between 30–40%
• Any RID is acceptable if milk/plasma ratio <1

Correct Answer: RID < 10%

Q15. Which class of drugs is associated with premature closure of the ductus arteriosus if used in the third trimester?

• Selective serotonin reuptake inhibitors (SSRIs)
• Nonsteroidal anti-inflammatory drugs (NSAIDs)
• Beta-lactams
• Insulins

Correct Answer: Nonsteroidal anti-inflammatory drugs (NSAIDs)

Q16. For a drug primarily eliminated by renal excretion, how should dosing typically be adjusted in the second trimester of pregnancy?

• Decrease dose because clearance is reduced
• Increase dose or frequency because renal clearance often increases
• No change because pregnancy does not affect renal elimination
• Abolish TDM because it is unreliable in pregnancy

Correct Answer: Increase dose or frequency because renal clearance often increases

Q17. Which oral hypoglycemic agent is generally preferred over sulfonylureas in pregnancy due to less placental transfer and better fetal outcomes when needed?

• Glyburide (glibenclamide)
• Metformin
• Pioglitazone
• Repaglinide

Correct Answer: Metformin

Q18. Which monitoring approach is recommended for lithium therapy in a pregnant patient?

• Stop monitoring because pregnancy stabilizes lithium levels
• Reduce dose empirically without measuring levels
• Monitor serum lithium levels more frequently and adjust dose due to GFR changes
• Switch to valproate without monitoring because it’s safer

Correct Answer: Monitor serum lithium levels more frequently and adjust dose due to GFR changes

Q19. Which statement best describes active transporters such as P-glycoprotein (P-gp) at the placenta and mammary gland?

• P-gp uniformly increases fetal exposure to all drugs
• P-gp can limit fetal exposure by effluxing substrates back to maternal circulation and also affect drug levels in milk
• P-gp only functions in the liver and has no role in placenta or lactation
• P-gp degrades drugs enzymatically in the milk

Correct Answer: P-gp can limit fetal exposure by effluxing substrates back to maternal circulation and also affect drug levels in milk

Q20. Which breastfeeding strategy can reduce infant exposure to a short-acting maternal medication that is considered necessary for the mother?

• Take the medication immediately before breastfeeding to maximize infant exposure
• Time dosing immediately after breastfeeding and avoid multiple daily doses around feeding times
• Double the maternal dose to reduce milk concentrations
• Interrupt breastfeeding permanently whenever the drug is taken

Correct Answer: Time dosing immediately after breastfeeding and avoid multiple daily doses around feeding times

Download