Which among the following can be seen in a partial mole?

AIIMS Raipur - 2017 (shift-2)

Obstetrics & Gynaecology

Easy

Appeared in: AIIMS Raipur - 2017 (shift-2)

Explanation

Partial hydatidiform moles are a form of gestational trophoblastic disease resulting from abnormal fertilization.
They are genetically characterized by a triploid karyotype, meaning they have 69 chromosomes (e.g., 69,XXY or 69,XXX).
This triploidy typically arises from the fertilization of a normal haploid ovum (23,X) by two separate haploid sperm, an event known as dispermy.
The presence of both maternal and extra paternal genetic material leads to the development of an abnormal placenta, often with some fetal tissue present.

Option B: Haploidy refers to a single set of chromosomes (23), as found in normal gametes (sperm and egg). A zygote with only a haploid set of chromosomes is not viable and is not a feature of molar pregnancy.
Option C: While technically correct that triploidy is a form of polyploidy (having more than two complete sets of chromosomes), 'Triploidy' is the more specific and precise answer that describes the classic genetic makeup of a partial mole.
Option D: A diploid karyotype (46 chromosomes) is characteristic of a complete hydatidiform mole, not a partial mole. In a complete mole, all 46 chromosomes are of paternal origin (androgenesis).

Visual 1: Diagram - An infographic illustrating the different fertilization events leading to a normal pregnancy (one egg + one sperm = diploid), a partial mole (one egg + two sperm = triploid), and a complete mole (empty egg + one/two sperm = diploid, androgenetic).
Visual 2: Table - A comparative chart detailing the key differences between partial and complete hydatidiform moles, including karyotype, pathology, presence of fetal tissue, hCG levels, and risk of progression to gestational trophoblastic neoplasia (GTN).

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Genetics of Gestational Trophoblastic Disease (Hydatidiform Mole) as background academic context rather than a clinical decision trigger.
Differentiating between partial and complete moles is critical for patient management and counseling. Complete moles carry a significantly higher risk (15-20%) of developing into malignant gestational trophoblastic neoplasia (GTN), such as choriocarcinoma, compared to partial moles (1-5%).
Nursing care post-evacuation involves serial monitoring of serum β-hCG levels to ensure they return to normal. A plateau or rise in hCG levels may indicate persistent trophoblastic disease, requiring further evaluation and possibly chemotherapy.
Patients must be counseled to use reliable contraception during the entire surveillance period (typically 6-12 months) to avoid a new pregnancy, which would confuse the interpretation of hCG levels.

How to Approach the Question

This is a factual recall question testing knowledge of reproductive genetics and pathology.
First, identify the core concept being tested: the genetic makeup of a 'partial mole'.
Recall or deduce the definitions of the ploidy levels given in the options: Haploidy (n=23), Diploidy (2n=46), Triploidy (3n=69), and Polyploidy (a general term for more than two sets of chromosomes).
Remember the key pathogenic event for a partial mole: the fertilization of one normal egg by two sperm (dispermy). This results in a zygote with three sets of chromosomes (one maternal, two paternal).
This 3n state is called triploidy.
Select 'Triploidy' as the most specific and accurate answer.

Concept Tested & Keywords

Concept Tested: Genetics of Gestational Trophoblastic Disease (Hydatidiform Mole)
Stem keywords: partial mole
Lead-in keywords: can be seen in

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