Molar pregnancy (aka hytadiform mole) is an abnormal pregnancy, where a non-viable fertilized egg implants in the uterus, and will fail to come to term.

• Heavy irregular vaginal bleeding in the 4th-5th month of pregnancy, that is painless
• Anemia → due to bleeding
• Hyperemesis (more vomiting than expected)
• HTN
• Proteinuria
• Sx of hyperthyroidism → extremely high hCG produced by the syncytiotrophoblast, mimics TSH because alpha-hCG is also found in TSH

• Characterized by presence of a hydatidiform mole (from Greek “hydatisia” meaning “a drop of water”, and Latin “mola” meaning “false conception&rdquo, where a mole is used to denote a clump of growing tissue, or a growth. It can be either:
  • Complete mole (most common, constituting 90%), where a single (incidence is 90%) or 2 (10%) sperm combines with an egg without a nucleus [thus without DNA], the sperm therefore reduplicating to form a "complete" 46 chromosome set. Because the egg has no maternal DNA, it has no function. Thus, it does not produce fetal tissue. It involves uncontrollable proliferation of cells in the syncytiotrophoblast (i.e. outer layer of the to-be-placental tissue, that connects more so with the uterine wall itself). The genotype is typicaly 46,XX (diploid) due to subsequent mitosis of the fertilizing sperm, but can also be 46,XY (diploid). 46,YY (diploid) is not observed. It has a higher risk of developing into a choriocarcinoma, a magliantn tumor of trophoblast cells [than do p artial moles]
  • Partial mole (10%), where a normal egg [with a nucleus] is fertilized by multiple sperm, causing an over-complete chromosome set, including triploid (69,XXY, 69 chromosomes, the most common), or tetraploid (92,XXXY, 92 chromosomes). Thus, it does produce fetal tissue, but because it has 3 chromosome sets rather than 2, it will be spontaneously aborted in late 1st trimester to early 2nd trimester. It involves uncontrolable proliferation of cells in the cytotrophoblast (i.e. inner layer of the to-be-placental tissue)

• A molar pregnancy is a gestational trophoblastic disease, which grows into a mass in the uterus that has swollen chorionic villi. Thus, it is a pregnancy related tumor
• These villi grow in clusters that resemble grapes
•  

• Extremities of age (<20yo, or >35yo)
• Hx of GTD → risk is 30% following Hx of 2 molar pregnancies
• Diets low in protein, folic acid, and beta carotene
• Use of oral contraceptive
• Cigarette use

• No fetal heart sound on Doppler auscultation
• On abdo palpation;
  • Uterus that is large for dates
  • Ovaries may be enlarged → ovarian/luteum cyst → hCG mimics FSH/LH which can cause luteum cysts
• FBC → anemia
• Coag studies → anemia
• Maternal Rh status → anti-D for Rh -ve mother
• Type and screen → high potential for bleeding, and need for transfusion

• hCG levels, in:
  • Complete mole, dramatically high, >100,000 → hCG is produced by the syncytiotrophoblast [in complete molar pregnancies]
  • Partial mole, mildly elevated → hCG is produced by the syncytiotrophoblast, and partial moles involve proliferation of the cytotrophoblast
• U/S, with a:
  • Complete mole, resembling a bunch of grapes ("snow storm appearance" instead of seeing a fetus)
  • Partial mole, with multiple defects (e.g. hydrocephalus, IUGR)
• Definitive Dx requires D&C, biopsy, and send for histology

• Tx ASAP to avoid risks of choriocarcinoma, including:
  • Baseline hCG, so you can compare before-and-after
  • Evacuate the uterus by:
    • Surgical D&C, preferred
    • Uterine suction
    • Carboprost (PGF2alpha, i.e. an oxytocic), to contract the uterus
  • Syntocin, to reduce PPH
  • Follow up with weekly serum hCG levels, until it has fallen to an undetectable level, usually 14 weeks for a complete mole, and 8 weeks for a partial mole
• Give prophylactic anti-D for Rh -ve mother, even though there isn't really a fetus present
• Cancer (i.e. invasive/metastatic moles) may require chemotherapy, and often respond well to methotrexate, due to the presence of paternal antigens
• Advised not to conceive for 1 year after a molar pregnancy, as the chances of having another molar pregnancy in this time is approximately 1%. This also allows to check hCG level has gone down consistently, indicating the molar has been completely eradicated

• More than 80% of hydatidiform moles are benign
• 12.5% of hydatidiform moles develop into invasive moles, called persistent trophoblastic disease (PTD)
• 2.5% of hydatidiform moles develop into choriocarcinoma (i.e. malignant, rapidly growing, metastatic form of cancer)
• Occurs in 0.1% of pregnancies, although geographically differs, with especially higher rates in Japan

• Ectopic pregnancy
• Miscarriage
• Gestational trophoblastic disease (category)