Singleton normal fetus with partial hydatidiform mole (PHM) pregnancy is a rare phenomenon. No previous reports have investigated the risk factors of gestational trophoblastic neoplasia (GTN) progression following this condition.

We retrospectively enrolled cases of singleton normal fetuses with PHM pregnancies at West China Second University Hospital, Sichuan University, from 2005 to 2017. Other cases were identified from PubMed databases during 1975 to 2021 for the cohort study. Cox proportional hazards models were applied to evaluate risk factors for GTN progression based on the patient's clinical characteristics.

Overall, 36 cases of singleton normal fetuses with PHM pregnancies were enrolled. After a median follow-up of 4.0 (0.8-12.0) months, nine (25.0%) patients progressed to GTN. Gestational age at pregnancy termination (hazard ratio [HR] 0.88; 95% confidence interval [CI] 0.78-0.99, p = 0.032), hyperthyroidism (HR 5.75; 95% CI, 1.16-28.50, p = 0.032), and reasons for pregnancy termination (medical indications vs. patients' choice; HR 0.25; 95% CI, 0.06-0.99, p = 0.049) were significantly correlated with GTN progression. Area under the receiver operating characteristic curve (AUC) of gestational age at pregnancy termination to predict non-progression to GTN was 0.784 (95% CI, 0.615-0.903, p < 0.001). A clinically significant cutoff value, that is, gestational age of 24 weeks, was determined by comprehensively considering the cutoff values of AUC and clinical significance of gestational age.

Compared to gestational age of pregnancy termination <24 weeks, ≥24 weeks was a protective factor for GTN. Therefore, there is enough evidence to continue pregnancy, except for uncontrolled severe complications, without increasing the risk of GTN progression.

Hydatidiform moles exhibit a distinctive gross appearance of multiple vesicles in the placenta. The advances in cytogenetic technologies have helped uncover novel entities of hydatidiform moles and enabled elaborate diagnoses. However, management of a vesicular placenta with a coexistent live fetus poses a bigger challenge beyond hydatidiform moles.

A 33-year-old woman was referred to our department for suspected hydatidiform mole coexistent with a live fetus at 24 weeks' gestation. The patient had conceived through double embryo transplantation, and first-trimester ultrasonography displayed a single sac. Mid-trimester imaging findings of normal placenta parenchyma admixed with multiple vesicles and a single amniotic cavity with a fetus led to suspicion of a singleton partial molar pregnancy. After confirmation of a normal diploid by amniocentesis and close surveillance, the patient delivered a healthy neonate. Preliminary microscopic examination of the placenta failed to clarify the diagnosis until fluorescence in situ hybridization showed a majority of XXY sex chromosomes. The patient developed suspected choriocarcinoma and achieved remission for 5 months after chemotherapy, but relapsed with suspected intermediate trophoblastic tumor.

We report a rare case of twin pregnancy comprising a partial mole and a normal fetus that resembled a singleton partial molar pregnancy. Individualized care is important in conditions where a vesicular placenta coexists with a fetus. We strongly recommend ancillary examinations in addition to traditional morphologic assessment in such cases.

To report the case of a partial molar pregnancy with live fetus and conduct a review of the literature regarding maternal and fetal complications associated to this condition.

Case report of a partial mole with a 33 weeks live fetus complicated by intrauterine growth restriction, oligohydramnios and severe preeclampsia. We report satisfactory maternal and neonatal outcomes and 1-year follow-up. A search was conducted in the Medline via Pubmed, Lilacs, Ovid, Uptodate and Google Scholar databases using the following MESH terms: hiditadiform mole, partial mole, live fetus, coexisting live fetus. Case series and case reports of pregnant women with coexisting partial mole and live fetus at the time of diagnosis were selected and information regarding maternal and fetal prognosis was extracted.

Initially, 129 related titles were identified. Of these, 29 met the inclusion criteria, and 4 articles were excluded due to failed access to the full text. Overall, 31 reported cases were included; 9 ended in miscarriage, 8 in fetal demise or perinatal death, and 14 (45 %) resulted in a live neonate. The most frequent maternal complication was preeclampsia in 6 (19.35 %) cases.

The coexistence of a partial mole with a live fetus poses a high risk of adverse perinatal outcomes and preeclampsia. The volume of information regarding this rare condition must be increased in order to better determine potential interventions in cases of euploid fetuses and to provide adequate counseling in clinical practice. Therefore, reporting these cases is important to build sufficient evidence about the natural course of this condition.

Diagnostic ultrasound has been in use in clinical obstetrics for close to half-a-century. However, in the literature, examination of the placenta appears to be treated with less attention than the fetus or the pregnant uterus. This is somewhat unexpected, given the obvious major functions this organ performs during the entire pregnancy. Examination of the placenta plays a foremost role in the assessment of normal and abnormal pregnancies. A methodical sonographic evaluation of the placenta should include: location, visual estimation of the size (and, if appearing abnormal, measurement of thickness and/or volume), implantation, morphology, anatomy, as well as a search for anomalies, such as additional lobes and tumors. Additional assessment for multiple gestations consists of examining the intervening membranes (if present). The current review considers the various placental characteristics, as they can be evaluated by ultrasound, and the clinical significance of abnormalities of these features. Numerous and varied pathologies of the placenta can be detected by routine ultrasound. It is incumbent on the clinician performing obstetrical ultrasound to examine the placenta in details and in a methodical fashion because of the far reaching clinical significance and potentially avoidable severe consequences of many of these abnormalities.

To evaluate cases of partial hydatidiform mole coexisting with a live fetus, including an observation of our own, and to discuss the proper antenatal management of women wishing to continue with a partial molar pregnancy.

A PubMed search was then undertaken, extending over the time period from 1975 to 2006, using the keywords 'partial hydratidiform mole', 'hydatidiform mole' and 'coexisting fetus'.

At 16 weeks of gestation, an ultrasonographic examination revealed a normal fetus with an extremely large, multicystic placenta. The woman was informed of future risks but wished to continue with the pregnancy. The pregnancy progressed until 28 weeks without any complication but ended spontaneously with a vaginal delivery; the fetus had died in utero. Pathologic examination of the placenta revealed areas of hydropic degeneration and necrosis. Including our own observation, 17 cases of partial hydatidiform mole associated with a fetus of normal karyotype have been documented.

Although the rate of adverse perinatal outcome is high, we still believe that if amniocentesis or fetal blood sampling reveals a normal karyotype, then continuing the affected pregnancy with close follow-up in tertiary centers is a feasible choice.

A 16 year review of persistent gestational trophoblastic tumour when the antecedent pregnancy was a partial hydatidiform mole.

Cases of persistent gestational trophoblastic tumour with partial hydatidiform mole as the antecedent pregnancy were reviewed for the period 1976 to 1992. DNA ploidy was analysed by flow cytometry.

A University Hospital which is a reference centre for gestational trophoblastic tumour.

The case notes of 207 women with persistent gestational trophoblastic tumour were reviewed.

A rise (or failure to fall) of beta hCG titre, or sign of metastasis.

Six (2.9%) women had partial hydatidiform mole as the antecedent pregnancy and all were initially judged to be low risk. However, two developed pulmonary metastasis; one woman developed persistent gestational trophoblastic tumour shortly after a hysterotomy, and none developed choriocarcinoma. The geometric mean of serum beta hCG concentrations at the initiation of chemotherapy was 868 mIU/ml (95% CI 114-1524). Of the six women, one achieved remission after total abdominal hysterectomy, and five after chemotherapy. The mean interval from starting treatment to remission was 68 days (95% CI 27.9-108.0). The initial beta hCG titre and interval were not statistically different from those found in cases of persistent gestational trophoblastic tumour when the antecedent pregnancy was not partial hydatidiform mole. Of the six, the DNA content was triploid in three and diploid in two. One of the two diploid cases required multiple courses of chemotherapy to achieve remission.

Partial hydatidiform mole can have malignant sequelae and can develop very soon after treatment. Its DNA content can be either diploid or triploid, the lungs being the most common site of metastasis. After evacuation of partial hydatidiform mole, immediate chest X-ray and regular follow up of the serum beta hCG level is necessary.

Current ultrasonographic techniques offer a novel approach for the identification of a wide variety of placental abnormalities usually described postnatally by the pathologist. Placental vascular lesions, placental tumors, and abnormal placentation are potentially associated with perinatal complications and their diagnosis in utero may influence the pregnancy management. An ultrasonographic classification of placental lesions that is based on their location, size, echogenicity, and number is proposed. Repeated ultrasonographic examination, together with biologic investigations, is important for the prenatal differential diagnosis of most these lesions and for full understanding of their pathophysiologic characteristics and significance.

Molar pregnancy with a coexisting live fetus is a rare occurrence. We present morphologic and cytogenetic analysis of a recent case. Cytogenetic studies revealed a 46, XX karyotype for the fetus, the normal placenta, and the abnormal placenta. Chromosome banding studies confirmed the presence of maternal and paternal chromosomes in all three tissues. These studies favored the possibility that both tumor and fetus arose from a single gestation. Subsequently, the patient required chemotherapy for low-risk, metastatic trophoblastic disease.

A hydatidiform mole associated with a fetus proved to be the result of twin gestation. On microscopic examination of the placenta the case was classified as a partial hydatidiform mole. Chromosomal markers were, however, consistent with a normal conception and a mole of diploid androgenetic origin. Chromosome analysis of a morphologic complete molar specimen yielded two cell lines, one consistent with a normal conception and one with diploid androgenesis. Twinning in molar specimens must therefore be considered, regardless of macroscopic appearance. The prenatal diagnosis of a coexisting fetus and molar placenta poses a real clinical problem; analyses must distinguish between a partial mole plus a triploid fetus and a normal fetus occurring with a partial or a complete mole. The distinction is important for decisions made during pregnancy and may be of prognostic significance after termination. The usefulness of chromosome marker analysis in distinguishing between the various origins is pointed out, and it is suggested that twin pregnancy with hydatidiform mole is more frequent than its description in the literature would suggest.

A review of 24 patients with a molar placenta and coexisting live fetus, including 2 new cases from the Queensland Trophoblastic Disease Registry, was made. The rate of fetal abnormalities was 33%; all 8 abnormal fetuses were female and in 5 of them in whom cultures were performed the chromosomal karyotype was triploidy 69XXX. There were 3 patients in whom malignant sequelae were detected (12%). After a confident ultrasound diagnosis of a molar placenta and a coexisting live fetus, the decision on whether the pregnancy should be terminated or allowed to continue should be based on the likelihood of the fetus being abnormal. It is recommended that the chromosomal karyotype and amniotic fluid alpha-fetoprotein level be determined by amniocentesis at about 16-18 weeks. This should allow those pregnancies in whom the fetus is potentially normal to be selected for conservative management.