Objective:To investigate the diagnosis and management of partial or complete hydatidiform mole with coexistent intrauterine pregnancy.Methods:Clinical data of 10 cases of hydatidiform mole with coexistent intrauterine pregnancy admitted to the Third Affiliated Hospital of Guangzhou Medical University, from September 2009 to May 2019 were retrospectively described.Results:(1) During the same period, 65 960 women were delivered at our hospital, and hydatidiform mole with coexistent intrauterine pregnancy was accounted for 1/6 596, among which complete hydatidiform mole and coexisting fetus (CHMCF) and partial hydatidiform mole and coexistent fetus (PHMCF) were found in four and six cases, respectively. The mean age of the ten patients were (30.9±4.1) years old, ranging from 26 to 35 years old, with 2.5 (1-4) times of pregnancies. Nine cases were identified at 22 +3 (12 +3-32 +3) gestational weeks and one at 9 + weeks. (2) Recurrent vaginal bleeding during pregnancy occurred in six cases, nausea and vomiting in three cases, and hyperthyroidism in mid- and late pregnancy in two cases. One patient developed preeclampsia and one case of severe mitral regurgitation with mild pulmonary hypertension. (3) In the 10 patients, the summit serum β -hCG level was 139 935 (16 990-546 033) U/L, and CHMCF and PHMCF patients were 212 500 (200 000-546 033) U/L and 60 768 (16 990-225 000) U/L, respectively. (4) The ultrasound results revealed a dark honeycomb area of the placenta in five cases, placental thickening in two cases, and vesicular placenta in one case. One case was found with bilateral giant luteinized ovarian cyst by ultrasound, multiple metastases in the left lower lobe of the lung by chest CT, multiple nodules in the pleural wall of the left lung by lung MRI, and CHMCF by pelvic MRI. In one case, ultrasound at 14 weeks of gestation showed interrupted fetal abdominal wall, visible mass, gastric bubble, liver, part of the intestinal echoes, and omphalocele. One case was found with embryo arrest. (5) The karyotype analysis of one case through amniocentesis was 46,XX with no anomalies, and chromosome microarray analysis was arr[hg19](1-22)×2. Prenatal diagnosis was refused in the remaining cases. (6) Among the ten patients, three were terminated by rivanol intra-amniotic injection, two received drug abortion, and uterine evacuation, and two with spontaneous abortion followed by curettage with a visible fetus and hydatidiform tissue. Total hysterectomy was performed in one patient due to partial invasion of the uterus by hydatidiform mole. One patient underwent a cesarean section on account of the left lower lung metastasis. One case developed preeclampsia at 33 +4 weeks of gestation and delivered two premature infants by cesarean section. Pathology examination found a complete and partial vesicular fetal mass in four and six cases, with P57 (－) and P57 (+), respectively. (7) During the follow-up, two women developed the persistent trophoblastic disease and received chemotherapy, while the remaining eight cases did not. Conclusions:When hydatidiform mole with coexistent intrauterine pregnancy is found, a timely differential diagnosis between CHMCF and PHMCF is needed. CHMCF is at a higher risk of abortion, intrauterine death, premature delivery, preeclampsia, and other maternal complications. Therefore, termination of CHMCF should be individualized. Most PHMCF patients have fetal malformation or fetal loss; thereby, timely termination is recommended.