Transvaginal ultrasound scan is the mainstay of diagnosis of miscarriage. Evidence based criteria should be fulfilled in all cases, with interval scans as needed to avoid inadvertent interventions when the pregnancy may be viable. Incomplete, inevitable and complete miscarriages have specific ultrasound findings. Several ultrasound factors, including slow embryonic heart rate, small embryo or gestation sac size and an enlarged yolk sac, alone or in combination, help predict impending pregnancy loss. Uterine factors such as fibroids, adenomyosis and adhesions after previous caesarean birth may make ultrasound assessment for early pregnancy more challenging.

Molar pregnancies, characterized by abnormal placental tissue growth, are rare but clinically significant conditions. Advancements in ultrasound and hCG assays have transformed the diagnosis of molar pregnancies. Maintaining a high index of suspicion is important for proper diagnosis, especially in cases of first-trimester vaginal bleeding. Certain clinical and laboratory features help distinguish between complete and partial molar pregnancies, including subtle sonographic findings and hCG levels. Histologic confirmation remains essential. The primary therapeutic approach for molar pregnancies is suction dilation and curettage, often with ultrasound guidance. Rhogam administration is important for Rhesus-negative patients, and uterotonics and blood products should be made immediately available during evacuation procedures. Hysterectomy is considered for presumed complete molar pregnancies in patients who have completed childbearing. Postoperative surveillance of serum hCG levels is critical for detecting postmolar gestational trophoblastic neoplasia. This case outlines diagnostic criteria for postmolar GTN, including hCG trends and potential complications. It also emphasizes the importance of contraception for accurate postoperative monitoring. Despite an increased risk of recurrence with a history of molar pregnancy, subsequent normal pregnancies are common following treatment. Early first-trimester ultrasounds and post-pregnancy hCG assessments are recommended for favorable outcomes in future pregnancies.

Gestational trophoblastic disease (GTD) incorporates a spectrum of placental related disorders, with both benign and malignant (Gestational trophoblastic neoplasia (GTN)) subtypes. Upon initial presentation, one should establish diagnosis (GTD versus GTN), the requirement for chemotherapy and whether monitoring has been concluded by a specialist trophoblastic centre. Women with a prior history of GTD or GTN that have completed monitoring, or early pregnant GTD patients, do not require specialist pregnancy management. Dissimilarly, early pregnant GTN patients, particularly those treated for high-risk disease, or women with a twin pregnancy involving a complete hydatidiform mole and viable co-existent foetus should receive detailed antenatal counselling and be managed under consultant-led care. Patients with a twin mole and viable co-existent foetus have a high risk of antenatal, intrapartum and post-partum complications. Fortunately, in women with a prior history of trophoblastic disease, live birth rates equal the general population, with no increased risk of disease relapse.