Gestational trophoblastic disease encompasses a group of conditions arising from the placental trophoblast. Among these, hydatidiform mole is the most common benign presentation, though it carries potential for malignant transformation into gestational trophoblastic neoplasia. In Nigeria and across sub-Saharan Africa, hospital-based studies often report higher baseline incidences compared to Western populations, making early recognition vital for midwifery practice. When a fertilisation error occurs, the placental tissue proliferates abnormally instead of forming a normal fetus.
Molar pregnancies are broadly categorised into two distinct genetic and morphological types. A complete mole develops when an anucleate egg is fertilised by a single sperm that subsequently duplicates its own chromosomes, meaning all genetic material is paternal. There is no embryonic or fetal tissue present. A partial mole occurs when a normal egg is fertilised by two sperm (or a single diploid sperm), resulting in triploidy. In partial moles, fetal parts or an abnormal fetus may be identified alongside hydropic placental villi.
Patients with a molar pregnancy often present with symptoms more exaggerated than a normal first-trimester gestation. Key clinical features include:
Confirmation of a molar pregnancy relies heavily on two primary investigations: pelvic ultrasonography and serum human chorionic gonadotropin quantification.
| Investigation | Complete Mole Finding | Partial Mole Finding | |
|---|---|---|---|
| --- | --- | --- | > |
| Ultrasound | Snowstorm appearance, absence of fetus | Thickened placenta with cystic spaces, fetal parts | |
| Serum hCG | Markedly elevated, often >100,000 mIU/mL | Moderately elevated for gestational age |
Doppler ultrasound may also show low-resistance, high-velocity blood flow within the uterine myometrium.
Once a molar pregnancy is diagnosed, prompt uterine evacuation is required to prevent maternal complications like severe haemorrhage, coagulopathy, or trophoblastic embolisation. Suction curettage (vacuum aspiration) is the preferred method regardless of uterine size, as it preserves the myometrium better than sharp curettage. Oxytocin infusion should be withheld until the cervix is dilated and suction begins, because premature oxytocution can push trophoblastic tissue into the maternal circulation. Midwives must prepare for heavy blood loss by securing intravenous access and having cross-matched blood ready.
Following uterine evacuation, meticulous follow-up is mandatory to detect persistent or malignant gestational trophoblastic neoplasia early. Serum hCG levels must be monitored weekly until they become undetectable for three consecutive weeks, then monthly for at least six months. Effective barrier or hormonal contraception must be enforced throughout this surveillance period. Conceiving too soon makes it impossible to distinguish between a new normal pregnancy and a rising hCG level caused by persistent trophoblastic disease.