Placenta is the organ that provides exchange of nutrients and waste products between mother and fetus. This develops by

Appeared in: OSSSC Nursing Officer-2021

Explanation

The placenta is a complex organ that begins its formation shortly after implantation.
It is formed from both fetal tissue (chorion frondosum) and maternal tissue (decidua basalis).
By the end of the third month of gestation (approximately 12 weeks), the placenta is structurally complete and fully functional.
After this point, it continues to grow in size and weight but its fundamental structure is established.

Option A: During the first month, placental development begins with the formation of primitive chorionic villi after implantation. However, it is not yet a fully formed or structurally complete organ.
Option C: By the fifth month, the placenta is already fully formed and functional. It continues to grow in size and mature to support the rapidly growing fetus, but its primary structural development is complete.
Option D: In the seventh month, the placenta is a mature organ. Its main activity is supporting the final stages of fetal growth. The fundamental structure was established much earlier in the pregnancy.

Clinical Relevance

Nursing practice connection: Knowing Timeline of placental development helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
A healthy, well-developed placenta is crucial for a healthy pregnancy outcome. Nurses monitor for signs of placental insufficiency, which can lead to fetal growth restriction.
Conditions like placenta previa (where the placenta covers the cervix) or placental abruption (premature separation) are serious obstetric emergencies requiring immediate nursing assessment and intervention.
Patient education on lifestyle factors that support placental health, such as good nutrition and avoiding smoking, is an important nursing role.

How to Approach the Question

First, identify the core question, which is about the completion of placental development.
Recall the key milestones in embryology and fetal development. The first trimester is the period of organogenesis (organ formation).
Differentiate between the initiation of a process and its completion. Placental formation starts in the first month.
Recognize that by the end of the first trimester (around 12 weeks or the third month), most major organ systems, including the placenta, are structurally complete.
Eliminate the later months (fifth and seventh) as these are periods of growth and maturation, not primary formation.
Select the third month as the time when the placenta becomes a complete and fully functional organ.

Concept Tested & Keywords

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E6 Midwifery Obstetrics and Gynecology Nursing Sandeep Kaur p. 50-61

E6 Anatomy Grays 43e Vol 1 Part 2 p. 5-7

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