A woman LMP 21 May 2019 then calculate EDD?

Appeared in: NORCET-7 Mains-2024

Explanation

The standard method for calculating the Expected Date of Delivery (EDD) from the Last Menstrual Period (LMP) is Naegele's Rule.
The formula for Naegele's Rule is: First day of LMP + 9 months + 7 days.
Applying the formula to the given LMP of 21st May 2019: Adding 9 months to May 2019 results in February 2020.
Adding 7 days to the 21st results in the 28th.
Therefore, the calculated EDD is 28th February 2020.

Option A: This option results from an incorrect calculation, likely by adding 10 months to the LMP instead of the standard 9 months.
Option B: This option represents a significant miscalculation of the months and is not aligned with any standard method for EDD estimation.
Option D: This option correctly adds 9 months to the LMP but omits the step of adding 7 days to the date.

Visual 1: Infographic - A clear, step-by-step infographic illustrating how to apply Naegele's Rule (LMP + 9 months + 7 days) with a calendar visual to track the months and days.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Calculation of Expected Date of Delivery (EDD) using Naegele's Rule as background academic context rather than a clinical decision trigger.
Accurate EDD calculation is fundamental in antenatal care for scheduling prenatal visits, timing of crucial screening tests (like for aneuploidy), monitoring fetal growth, and making decisions about labor induction if the pregnancy goes post-term.
Nurses frequently perform or verify EDD calculations and must educate expectant mothers about their due date and the timeline of their pregnancy.
What if the woman had highly irregular menstrual cycles? In such cases, Naegele's rule is unreliable. The EDD would be more accurately determined by an early first-trimester ultrasound measuring the crown-rump length (CRL) of the fetus.

How to Approach the Question

First, identify that the question asks for the Expected Date of Delivery (EDD) based on a given Last Menstrual Period (LMP).
Recall the standard formula for this calculation, which is Naegele's Rule: EDD = LMP + 9 months + 7 days.
Break down the calculation into simple steps. Start with the date: 21st May 2019.
Add 7 days to the date: 21 + 7 = 28.
Add 9 months to the month: May is the 5th month. Adding 9 months takes you to the 14th month, which is February of the following year.
Combine the results: 28th February 2020. Check this against the given options.

Concept Tested & Keywords

Concept Tested: Calculation of Expected Date of Delivery (EDD) using Naegele's Rule.
Stem keywords: LMP, 21 May 2019, calculate EDD
Lead-in keywords: calculate
Clinical cues: LMP: 21 May 2019

Q6kXgHBO6Nbd9cSgA8PLrI

Practise the full NORCET-7 Mains-2024

Attempt every question from this paper in a timed mock, then review the full solution for each one.