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Molar Pregnancy and Gestational Trophoblastic Disease - NEET PG OBGYN

Feb 15, 2023

Molar Pregnancy and Gestational Trophoblastic Disease - NEET PG OBGYN

Molar pregnancy is an important topic for the NEET PG exam because it is a rare but serious type of gestational trophoblastic disease (GTD) that can have significant implications for the health of the mother and the developing fetus. 

In the NEET PG exam, questions related to molar pregnancy can be included in the obstetrics and gynecology section and can test a candidate's knowledge and ability to diagnose and manage gestational trophoblastic diseases. 

Read this blog further to get a quick overview of this important obstetrics and gynecology topic for NEET PG exam preparation.

Normal Reproduction

Normal Reproduction

Pathogenesis of molar pregnancy  

  • Formation of partial mole: If Oocyte is fertilized by 2 sperms  
Pathogenesis of molar pregnancy  
  • Partial Mole
    • Fetus that is partly degenerated by vesicles.
    • It causes Choriocarcinoma in only 2-3% cases (almost not seen)
    • Better prognosis than complete mole.
    • It can also be, 69XXX (mainly), 69XYY, 69 XXY and can never be 69 YYY
  • Complete mole
Pathogenesis of molar pregnancy  
  • It can be 46 XX (mainly), 46 XY and can never be 46 YY.
  • The degenerated villi formation occurs: Start imbibing fluid and numerous vesicles appear
  • There is 20% risk of choriocarcinoma.
  • Aborts by itself (12- 16 week) 
  • Difference between partial and complete mole

Complete mole

Partial mole


Fetal or embryonic tissue



Hydropic Swelling of villus



Trophoblastic hyperplasia



Implantation site trophoblast

Marked atypia

Mild atypia


46 XX (mainly), 46 XY

Triploid (69XXX)

Complete mole types

NEET PG Elite Plan

Presentation of complete mole 

  • M / C: Bleeding 
  • ↑↑ BP 
  • Hyperthyroidism as HCG acts similar to TSH
  • Rarely passage of grape like vesicles (rare) 
  • Uterine size > POG 
  • Hyperemesis (due to HCG ↑) 

Also Read: Endometriosis and Adenomyosis - NEET PG OBGYN

Mx of complete mole 

  • Any size: Suction / Evacuation, followed by check curettage (after 1 week) because there might be retained bits 
  • Chest X-ray because it is M / C site of Mets
  • HCG values: Should be followed for at least 6 months after it comes negative 
    • HCG comes negative in 9 weeks: Complete mole 
    • HCG comes negative in 7 weeks: Partial mole 
Important Information 

In the follow up period of 6 months, there should not be any pregnancy and we give contraception.


  • Persistence of Trophoblastic tissue is confirmed by 
    • Continuous bleeding occurs 
    • High HCG >100000 
    • Persistently ↑↑ HCG ± 10% of previous value 
    • Bulky / Enlarged uterus 
  • If there is confusion at HPE of Complete Mole or partial Mole: P57 KiP 2 immune staining is done; P57 in immune staining only seen with maternal contribution in the Karyotype, in partial mole
    • Complete mole will not show P57 KiP2 staining. 
  • High Risk of Choriocarcinoma is seen with 
    • HCG > 105
    • Very large uterus 
    • Theca Lutein cysts (high HCG) > 6cm size 
  • Invasive mole
    • Does not follow normal pregnancy 
    • Marker: HCG 
    • Surgery is mainstay of treatment 
  • Choriocarcinoma 
    • Marker: HCG 
    • Chemotherapy is treatment of choice 
    • For older women hysterectomy can be done
  • Placental site trophoblastic tumor 
    • Marker: HPL (from cytotrophoblast, and its derivative intermediate trophoblast)
    • Hysterectomy is best management


  • WHO classification for risk assessment/prognosis
Risk factor0124
Age= 39> 39
Antecedent pregnancyHydatidiform MoleAbortionTerm
Interval (months) from antecedent pregnancy<44 to 67 to 12> 12
Human chorionic gonadotropin (HCG) (IU/L)6<103-104-105>105
ABO blood group (female x male)0 x A
A x 0
Largest tumor mass, including uterine (cm)3-5>5
Site of Metastases
Number of metastases
GI tract
> 8
Prior chemotherapySingle drugTwo or more
  • WHO classification was used earlier, which includes blood groups also.
  • But now it has been replaced by FIGO classification, which says blood group is not considered as a risk factor 
  • FIGO Scoring
FIGO Scoring0124
Age (years)<40≥40--
Antecedent pregnancyMoleAbortionTerm
Interval months from end of index
pregnancy to treatment
<44 to <77 to <13≥13
Pretreatment serum hCG (IU/l)< 10 310 3 to <10 410 4 to <10 5≥ 105
Largest tumour size, including uterus (cm)< 33 to < 5≥5-
Site of metastasesLungSpleen, kidneyGastro intestinalLiver, brain
Number of
Previous failed chemotherapySingle drug2 or more drugs
  • Low Risk score <7
    • High Risk score ≥ 8
  • Staging of trophoblastic Disease (Choriocarcinoma)
StageSite of MetastasisPrognosisManagement
IUterusGoodSingle Agent Chemo
IIPelvisBased on scoringif Low score: Single agent chemoIf High score: Multi agent chemo
IIILung metastasisBased on scoringIf Low score: Single agent chemoIf High score: Multi agent chemo
IVDistant MetastasisPoorMulti agent chemo is used
  • MC site of metastasis is lungs 
  • 2nd MC site of metastasis: Vagina (sub urethral nodule): This appears as a bluish spot in the vaginal area and if you take biopsy of this area, severe hemorrhage can occur, which cannot be controlled by suturing & urgent Radiotherapy needs to be given to control it.

Also Read: Postpartum Hemorrhage: Causes, Types and Management - OBGYN

Previous Year Questions

Q. Patient with 10 weeks of amenorrhea, size of uterus 12 to 14 weeks, with severe nausea and vomiting, snow storm appearance on ultrasound, management? (AIIMS 2020)

A. Follow up with hCG levels

B. Continue pregnancy

C. Suction and Evacuation

D. Diagnostic Laparoscopy

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