If the LMP is August 5th, what is the expected date of delivery (EDD)?

Appeared in: AIIMS Rishikesh NO - 2019

Explanation

Naegele's rule is a standard method used to estimate the due date in pregnancy.
The formula involves adding 9 calendar months and 7 days to the first day of the Last Menstrual Period (LMP).
Starting with the LMP of August 5th, adding 9 months brings the date to May 5th.
Adding 7 days to May 5th results in the final Expected Date of Delivery (EDD) of May 12th.

Option A: This date is the result of an incorrect calculation and does not follow Naegele's rule.
Option C: This date is incorrect. It might be the result of miscalculating the number of months, for instance, adding 10 months instead of 9.
Option D: This represents an incomplete calculation. It is the date after adding 9 months to the LMP but before adding the required 7 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 crucial for scheduling prenatal care, monitoring fetal growth, and timing essential screenings and interventions.
The EDD helps clinicians classify the pregnancy as preterm, term, or post-term, which guides important decisions such as the induction of labor.
What if? If a patient has highly irregular menstrual cycles, Naegele's rule is considered unreliable. In such cases, an early first-trimester ultrasound is the most accurate method for determining the gestational age and EDD.

How to Approach the Question

Identify the key information provided in the question: the Last Menstrual Period (LMP) is August 5th.
Recall the standard formula for calculating the Expected Date of Delivery (EDD), which is Naegele's rule.
Apply the rule: Add 9 months and 7 days to the LMP.
First, add 9 months to August 5th. Counting forward: September (1), October (2), November (3), December (4), January (5), February (6), March (7), April (8), May (9). This brings the date to May 5th.
Next, add 7 days to May 5th. This gives the final EDD of May 12th.
Compare the calculated date with the given options to select the correct answer.

Concept Tested & Keywords

Concept Tested: Calculation of Expected Date of Delivery (EDD) using Naegele's rule.
Stem keywords: LMP, August 5th, expected date of delivery, EDD
Lead-in keywords: what is

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E6 Comprehensive Textbook of Community Health Nursing for BSc Nursing Students Part 2 — Subpart A (pp 1-275 of 550) p. 195-197

E6 Obstetrics Williams p. 19-35

Practise the full AIIMS Rishikesh NO - 2019

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