Introduction/Background Complete hydatidiform mole with a coexisting viable foetus (CHM-CF) occurs in 1/22.000–100.000 pregnancies and, in these cases, the pregnancy is frequently terminated once diagnosis is made.

Given the lack of evidence regarding the effect of delivery mode on obstetric and oncologic outcomes, we performed a systematic review of the literature to evaluate the oncologic and obstetric outcomes of women with CHM-CF who delivered a viable foetus.

Methodology We systematically searched three databases (Pubmed, Embase, Cinahl) from 1982 to 2020 for articles published in English. We selected articles reporting at least two cases of CHM-CF with at least one alive neonatal birth occurring after 24 gestational weeks with histological confirmation of complete mole.

Results We included 22 articles: 6 case reports and 16 retrospective case series for a total of 97 CHM-CF pregnancies. Persistent trophoblastic disease (PTD) occurred in 34% (13/38), choriocarcinoma in 2% (1/38) and pulmonary metastasis in 10% (4/38) of cases. When treatment information was available, methotrexate was the only reported therapy. No cases of maternal deaths were observed.

The risk of PTD was not associated to either the gestational age at delivery or to the delivery mode (vaginal versus caesarean delivery) while advanced maternal age was associated with an increased risk of PTD.

The average gestational age of delivery was 33 weeks; 31% of women delivered at term (23/73) and 68% preterm (50/73), 61% after 32 weeks and 23% before 28 weeks. Obstetric complications were present in 67% of pregnancies and were the following: vaginal bleeding 53%, preeclampsia 18%, hyperthyroidism 17%. Preeclampsia was the most common indication for iatrogenic preterm delivery.

Conclusion CHM-CF pregnancy is an obstetric challenge; pregnancy can be continued if no complications occur which might lead to delivery, either spontaneous or iatrogenic. The mode of delivery is not associated with a higher rate of PTD.

Disclosures The authors declare that they have no conflict of interest.