NCLEX Pharmacology: Therapeutic Drug Levels & Antidotes Study Guide
Medications with a narrow therapeutic index (NTI) and life-saving antidotes represent high-frequency test items on the Next Generation NCLEX (NGN).
Table of Contents
When it comes to OB/Maternity nursing, distinguishing between the different signs of pregnancy is a guaranteed topic on the NCLEX. You must know the difference between what a patient feels, what a provider observes, and what provides absolute proof of a fetus.
Use our comprehensive cheat sheet below to master the 3 P’s (Presumptive, Probable, and Positive signs) and learn exactly how to calculate a due date using Naegele’s Rule!
1. The 3 P’s: Signs of Pregnancy
Pregnancy signs are broken down into three categories based on how definitive they are. Note: Presumptive and Probable signs are NOT definitive diagnoses, as these symptoms can be caused by other underlying conditions!
| Category | Type of Sign | Clinical Examples |
|---|---|---|
| Presumptive (Possible Signs) |
Subjective Reported by the patient |
|
| Probable (Likely Signs) |
Objective Observed by the provider |
|
| Positive (Conclusive Signs) |
Definitive Can ONLY be attributed to pregnancy |
|
2. Calculating EDD (Naegele’s Rule)
Once pregnancy is confirmed, you need to calculate the Estimated Delivery Date (EDD). The standard tool for this is Naegele’s Rule, which bases the calculation on the woman’s Last Menstrual Period (LMP).
This formula assumes a standard 28-day menstrual cycle and a gestation lasting 280 days (40 weeks), with no leap years.
The Formula
First Day of LMP – 3 Months + 7 Days + 1 Year
Let’s Look at an Example:
Scenario: A patient states the first day of her last menstrual period was May 4th, 2022.
- Step 1 (Minus 3 Months): May 4th ➔ February 4th, 2022
- Step 2 (Plus 7 Days): February 4th ➔ February 11th, 2022
- Step 3 (Plus 1 Year): February 11th, 2022 ➔ February 11th, 2023
Recommended Test Banks for this Topic:
Ready to crush your exams?
Get instant access to thousands of practice questions and detailed rationales.
Browse All Maternity Test BanksRelated Study Guides
Pharmacology Prefixes and Suffixes: The Ultimate NCLEX Cheat Sheet
Memorising hundreds of individual generic and brand-name medications for nursing school and the Next Generation NCLEX (NGN) can feel overwhelming.
NCLEX Study Guide: Cranial Nerves Made Easy (Mnemonics & Assessment)
Cranial nerves are a set of twelve pairs of nerves that emerge directly from the brain. They primarily innervate structures