Twin pregnancy with a coexisting hydatiform mole and liveborn infant: complicated by maternal hyperthyroidism and neonatal hypothyroidism

Delivery of Euthyroid Baby following Hyperthyroidism in Twin Gestation with Coexisting Complete Hydatidiform Mole

Context

Gestational trophoblastic disease (GTD) is a rare complication of pregnancy, ranging from molar pregnancy to choriocarcinoma. Twin pregnancies with GTD and coexisting normal fetus are extremely rare with an estimated incidence of 1 case per 22,000–100,000 pregnancies. Molecular mimicry between human chorionic gonadotrophin (hCG) and thyroid-stimulating hormone (TSH) leads to gestational trophoblastic hyperthyroidism (GTH) which is further associated with increased maternal and fetal complications. This is the first reported case in literature describing the delivery of a baby with biochemical euthyroid status following a twin pregnancy with hydatidiform mole (HM) associated with gestational trophoblastic hyperthyroidism (GTH).

Case Description

A 24-year-old G4 P3 Caucasian female with twin gestation was admitted to hospital for gestation trophoblastic hyperthyroidism. She was later diagnosed to have twin pregnancy with complete mole and coexisting normal fetus complicated by gestational trophoblastic hyperthyroidism (GTH). Despite the risk associated with the continuation of molar pregnancy, per patient request, pregnancy was continued till viability of the fetus. The patient underwent cesarean section due to worsening preeclampsia and delivered a euthyroid baby at the 24th week of gestation.

Conclusions

Twin pregnancy with gestational trophoblastic disease and coexisting normal fetus is associated with high risk of hyperthyroidism, and careful monitoring of the thyroid function test along with dose titration of thionamides is of utmost importance throughout the gestation. If normal thyroid hormone levels are maintained during the pregnancy, euthyroidism could be successfully achieved in the baby.

Management of a dichorionic twin pregnancy with a normal fetus and an androgenetic diploid complete hydatidiform mole

We describe a rare case of complete hydatidiform mole with twin live fetus (CHMTF) confirmed by histopathology, flow cytometry, and polymerase chain reaction techniques. No malformations were observed, fetal karyotype was normal and β-human chorionic gonadotropin levels were increased (>100,000 IU/ml). Once the patient had been informed of the risks, it was decided to continue the pregnancy, but termination of pregnancy was necessary at week 13 + 5 due to maternal complications consisting of hyperthyroidism, hypertension and vaginal bleeding, followed by persistent trophoblastic disease (PTD). Patients diagnosed with CHMTF should be informed of all known risks, including the considerable risk of PTD, which is similar to - or according to some reports - even higher than that associated with a singleton complete mole and is not increased by continuing pregnancy. Due to the low number of series published, evidence-based clinical management guidelines are lacking.