Molar pregnancy (Complete) Flashcards
(31 cards)
Define molar pregnancy
Spectrum of gestational trophoblastic disease caused due to imbalance between maternal and paternal chromosomes during conception
How common is molar pregnancy?
1 in 1000-2000 (rare)
Molar pregnancy is alternatively known as?
Hydatidiform mole
What are the two main types of molar pregnancies?
Complete mole
Partial mole
What is the aetiology of a complete mole
Formed by conception between a single sperm and an egg containing no genetic information
Sperm replicates to form a normal number of chromosomes all paternal in origin.
No foetal tissue present only proliferation of swollen chorionic villi
What histological findings are seen with complete mole?
No foetal tissue
Proliferated swollen chorionic villi
What is the aetiology of a partial mole?
Formed from two sperm and a normal egg.
Both paternal and maternal genetic material are present
There is variable evidence of foetal parts.
What are the key differences between a complete mole and partial mole?
Genetic material:
- Complete mole: 1 sperm and 1 non-genetic containing egg
- Partial mole: 2 sperm and 1 egg
Tissue:
- Complete molar: no foetal tissue and proliferated swollen chorionic villi
- Partial molar: Contains some foetal tissue
What are the main risk factors for molar pregnancy?
Extremities of age (>35)
Previous molar pregnancy
What are the main clinical features of molar pregnancy?
Timeframe: First trimester of pregnancy
Bleeding:
Vaginal bleeding
- Usually heavy and prolonged but may vary
- Passage of hydropic villi (in some cases)
Anaemia
Hormonal:
Thyrotoxicosis
Severe nausea and vomitting (due to very high hCG levels)
Uterine/obsteric:
Uterine enlargement
- Beyond gestational age
- Due to trophoblastic proliferation and retention of blood
Early-onset pre-eclampsia
Cardiopulmonary complications:
SoB
Respiratory distress
Why does thyrotoxicosis occur in molar pregnancies?
hCG closely resembles TSH and is hence able to activate its receptors
Why does uterine enlargement occur in molar pregnancy?
Due to excessive growth of trophoblasts and retained blood
Why can SoB and respiratory distress occur in patients with molar pregnancy?
Diaphragmatic compression due to enlarged uterus
High cardiac ouput failure (due to thyrotoxicosis)
Severe clampsia
Anaemia
What differentials should be considered alongside molar pregnancy?
Ectopic pregnancy
Miscarriage
Normal pregnancy
What investigations should be considered in patients with suspected molar pregnancy?
Bedside:
Basic obs: Check for pre-eclampsia
Examination of pregnant abdomen: Enlarged uterus
Speculum examination: Check for miscarriage
Bloods:
B-hCG levels
- Significantly higher than normal pregnancy
FBC: Check for anaemia
Group and save: If blood transfusion needed
Imaging:
Trans-vaginal ultrasound
- Snowstorm appearance
- Absence of foetal tissue
- Low resistance of blood vessel flow
Pregnancy tissue sampling and histology: Definitive diagnosis and differentiation for partial and complete
What investigation can provide a definitive diagnosis for GTN?
Histological testing
(Also needed to differentiate between complete and partial)
N.B. Can still diagnosed GTN without histological testing however wont be definitive
What findings on transvaginal ultrasound are suggestive of molar pregnancy?
Snowstorm appearance
Absence of foetal tissue
Low resistance of blood vessel flow
What B-hCG findings are typically seen in molar pregnancy?
Very elevated (>100,000)
What is the management plan for molar pregnancy?
Immediate referral to specialist centre
Surgical:
Suction curettage: First-line if fertilisation preservation
Hysterectomy: Can be used if fertilisation preservation not required
Medicine:
Anti-D immunoglobulin: If rhesus D-negative
Chemotherapy: If malignancy detected (choriocarcinoma) or prophylaxis if high-risk
Surveillance:
Complete mole:
- Follow-up > 6 months if hCG returns to normal within 56 days
- Follow-up < 6 months if hCG fails to return to normal within 56 days
Partial mole:
Follow-up complete once the hCG has returned to normal on two samples, at least 4 weeks apart.
Advised not to conceive until follow-up complete
What is first-line definitive management for molar pregnancy?
Surgical curettage
What surgical option may be considered in patients who dont have intention of concieve?
Hysterectomy
What must always be given for patients who are rhesus D-negative?
Anti-D immunoglobulins
When is chemotherapy considered in management of molar pregnancy?
If confirmed malignancy (e.g. choriocarcinoma)
If at high-risk (prophylaxis)
Follow-up should be planned within which timeframe in patients with complete moles?
> 6 months (if hCG normal within 56 days)
< 6 months (if hCG not normal within 56 days)
