Partial hydatidiform mole and coexistent live fetus with placenta previa: a case report

Introduction and importance:

Partial molar pregnancy with a coexistent live fetus is very rare. This type of mole mostly ends in the early termination of pregnancy due to an abnormally developed fetus.

Case presentation:

Here, we report a case of a 24-year-old Indonesian woman with an ultrasonographic appearance of partial hydatidiform mole with initial placenta covering the internal uterine ostium in the late first trimester which then became marginal placenta previa in the third trimester. The woman decided to continue the pregnancy after considering the risks and benefits. The normal anatomy of the premature infant was vaginally delivered alive with a large and hydropic placenta.

Clinical discussion:

Proper diagnosis, management, and monitoring remain challenging as this case is still rarely reported. Although embryos from partial mole forms generally do not survive since the first trimester, our case reported the singleton pregnancy with the coexistent normal fetus and the partial mole characteristic of the placenta. Diploid karyotype, few and focal extent of hydatidiform tissue of placenta, low rate of molar degeneration, and the absence of fetal anemia hypothesized as the factors that influenced survival of the fetus. There were two maternal complications such as hyperthyroidism and frequent vaginal bleeding without subsequent anemia in this patient.

Conclusions:

A rare case of partial hydatidiform mole coexistent with a live fetus with placenta previa was reported in this study. There were also maternal complications. Thus, prompt and regular monitoring of maternal and fetal condition holds an important role.

Introduction

Highlights

• Partial molar pregnancy with a coexistent live fetus is very rare.

• There were many factors that affected the maternal-fetal survival.

• Prompt and regular monitoring of maternal-fetal condition holds an important role.

Hydatidiform mole is one of the categories of gestational trophoblast disease. Although classified as a benign tumor, this disease is premalignant because it has the potential to become malignant and invasive. The term ‘hydatidiform mole’ was taken from the Greek ‘Hydatis,’ meaning water drop, and the Latin ’molar,’ meaning mass1. WHO reports the incidence of hydatidiform mole around one per 1500 pregnancies and one per 600 therapeutic abortions in the USA. The highest prevalence is found in Southeast Asian and Japanese women, with rates ranging from one per 500 pregnancies2,3.

This molar pregnancy is classified into complete hydatidiform mole (CHM) and partial hydatidiform mole (PHM). PHM includes the presence of several fetal tissue elements and chorionic villous changes that undergo hydropic degeneration. These changes are usually focal. Cytogenetically, PHM pregnancies are usually triploid as a result of the fertilization of one normal ovum and two sperm (dyspermia). The karyotypes of the products of conception are 69,XXX; 69,XXY; or 69,XYY. Case reports regarding PHM pregnancies with a living fetus such in this case are very rare because the fetus is generally malformed. In addition, triploid fetuses tend not to survive since the first trimester4.

Several studies report the case of PHM with surviving fetuses but they are still very rare. Fetuses that survive usually have a diploid karyotype. To date, only 20 cases have reported PHM pregnancies with a single fetus with a diploid karyotype. Six of these cases successfully delivered babies with diploid karyotypes. Five cases were born by cesarean section, while the other one was delivered vaginally5,6.

This case report presents a very rare case, namely a PHM in which the fetus survived 32–33 weeks’ gestation without any abnormalities in its anatomical structure accompanied by placenta previa.

Case report

This following case is described according to the SCARE guideline7. A 24-year-old Indonesian woman, in her first pregnancy, nullipara, presented with vaginal bleeding without uterine contractions at 13 weeks of gestation in the Department of Obstetrics and Gynecology of Slamet General District Hospital. This complaint was more severe than the previous complaint, with spotting vaginal bleeding since 8 weeks of gestation. The patient had never undergone a pregnancy program. The patient’s older sister had a history of abortion at the age of gestation of 8 weeks. The patient’s mother-in-law had a history of abortion twice and one of them was a twin pregnancy. The patient denied taking sex hormone drugs.

Physical examination revealed a normal result. External obstetric examination showed gestation age based on fundal height was over than gestational age based on the last menstrual period. Fluxus was found flowing from the external os of the uterus during the inspection.

Ultrasonography (US) demonstrated a fetus with normal anatomy and an appropriate amniotic fluid volume. An abnormally thickened, single, Swiss cheese–like appearance of the placenta implanted in the internal os of the uterus was also observed (Fig. 1).

Figure 1.

Ultrasonography revealed abnormally thickened, single, Swiss cheese appearance with placenta previa.

During admission, the hemoglobin was 11 mg/dl. The serum β-human chorionic gonadotropin (β-hCG) was over 300 000 mIU/mL at 20 weeks of gestational age. Thyroid profile revealed low thyroid-stimulating hormone (<0.05 mIU/ml; normal range: 0.27–4.7 mIU/ml) and high T3 (3.6 ng/ml; normal range: 0.61–1.81 ng/ml) and free T4 (1.66 ng/ml; normal range: 0.81–1.51 ng/ml). This laboratory result was corresponding to hyperthyroidism. However, no significant symptoms and signs was consistent with hyperthyroidism in the woman. The remaining laboratory workup (liver enzyme, blood platelets, creatinine, urinalysis) and chest x-ray examination were within normal limit. Due to limited resources, amniocentesis could not be conducted.

The patient was informed of the risk of preterm birth and trophoblastic disease. The patient decided to continue the pregnancy as the fetal structure was still normal. The patient was advised to take a daily multivitamin (folic acid, ferrous sulfate, and calcium), progesterone pill, and isoxsuprine HCl. The woman decided to continue the pregnancy after considering the risks and benefits.

During 32–33 weeks of gestation, the patient experienced increased vaginal bleeding without abdominal pain and was admitted to the hospital. The US revealed a normal fetus and marginal placenta previa. The single and large multicystic placenta persisted, however, it ‘migrated’ superiorly. The distance between the edge of placenta and internal ostium was ∼1.5–2.0 cm. The baseline fetal heart rate was 150 bpm. The hemoglobin was 13.7 mg/dl.

Four days after the last admission, the patient experienced similar vaginal bleeding and abdominal pain. The patient had been in active phase of labor. One hour after arriving at the hospital, the patient vaginally delivered a 42-cm long live male baby with birthweight of 1850 g. The 1-, 5-, and 10-min Apgar scores were 7, 8, and 8, respectively. The uncomplicated delivery was predicted due to the small birthweight. The estimated blood loss was ∼150 ml.

The placenta, which was large, size of 14×14×4 cm, and hydropic and was recovered manually (Fig. 2). The discoid placenta’s weight was 900 g. The ‘grape-like areas’ were observed, which occupied ∼10% of the peripheral surface. Histopathological examination of the placenta revealed a large-sized and medium-sized irregular chorionic villi with numerous gross nodular swellings. Variable trophoblastic hyperplasia was focal in the villous surfaces.

Figure 2.

The placenta was large and hydropic.

The postpartum neonatal karyotype analysis was diploid (46,XY). β-hCG concentration was 1000 mIU/ml after delivery and by the 4 weeks after delivery, it was negative (<5 mIU/ml). The mother had a negative result on 11 consecutive months and no metastases were found.

Discussion

The present study reports a case of a 24-year-old Indonesian woman with a partial molar pregnancy and live birth of an infant.

Hydatidiform mole is the subcategory of gestational trophoblastic disease, originating from the gestational tissue and can metastasize. CHM forms after the fertilization of two sperms, 23,X and 23,Y (dyspermia), and an ovum, resulting 46,XX or 46,XY with poor fetal anatomy. This karyotype is a heterozygote, however, still androgenetic. Although very rare, dizygotic twins consisting of one normal baby and one CHM may occur4. CHM has a higher incidence of malignant sequelae compared with partial moles. In most studies, 15–20% of complete moles show signs of persistent trophoblastic disease. Early evacuation of the mole does not reduce this risk8.

Partial mole forms as slowly progressive swelling within the stroma of the chorionic villi which is usually avascular, while the vascular villus perfused by functioning fetal placental circulation is not affected. Cytogenetically, PHM is usually triploid as a result of the fertilization of one normal ovum and dyspermia (diandrogenetic). The products of conception can be 69,XXX; 69,XXY; or 69,XYY. Embryos generally do not survive in the first trimester4. However, there are several cases that reported a diploid karyotype and the fetus can survive. However, cases like this are still rarely reported5. The risk of persistent trophoblastic disease after a partial mole is much lower than after a complete mole. Study reported that only three out of 3000 partial moles became choriocarcinoma9.

Hydatidiform mole accompanied by the presence of a fetus is not always categorized as a partial mole. There are three categories for this condition: (1) twin pregnancy with one normal fetus (normal placenta) and another complete mole (the most common), (2) twin pregnancy with one normal fetus (normal placenta) and another partial mole, (3) singleton pregnancy with one normal fetus and partial mole of the placenta (the rarest)10. Our case reported the singleton pregnancy with coexistent normal fetus and the partial mole characteristic of the placenta.

US is the main modality to diagnose hydatidiform mole4. The US usually showed the Swiss cheese–like appearance or honeycomb-like echo in the placenta11. The border between the honeycomb echo and the normal placental tissue is not clear, and most fetuses are malformed. Few ultrasonographic prenatal findings are structurally normal4. The present case reported Swiss cheese–like appearance in the part of the placenta with coexisting normal structures of fetus at 20 weeks of gestation.

CHM mostly reported significantly higher hCG level than that in PHM. Less than 10% of PHM cases were greater than 100 000 mIU/ml1. However, a high hCG level was found in the present case, which might be related to the large proportion of hydropic tissue in the placenta.

Most of the fetal chromosome karyotypes are triploid (90%) and most pregnancies end in abortion and fetal death6. This case revealed diploid karyotyping analysis and the normal male baby was delivered. The placental microscopic finding was consistent with a partial mole.

Termination of pregnancy is usually done after diagnosis of hydatidiform mole. Continuation of pregnancy can be other choice if the fetus develop normally. However, it is necessary to ask for informed consent to the pregnant woman of possible maternal and fetal complications, such as vaginal bleeding, preeclampsia, hyperthyroidism, and theca lutein ovarian cysts. After diagnosis of PHM, we first considered to terminate the pregnancy. However, the prediction of further development of normal fetus and live birth under proper management overweighed the prediction of complications in the present case. We had confirmed that the pregnant woman chose to continue her pregnancy.

Some factors may influence survival of fetus in PHM: (1) normal karyotype of fetus, (2) smaller size of grape tissue of placenta, (3) the rate of molar degeneration, (4) nonanemia state of fetus, and (5) the absence of maternal complications such as preeclampsia, thyrotoxicosis, and profuse vaginal bleeding12. Our case described some of these factors, such as diploid karyotype, few and focal extent of hydatidiform tissue of placenta, low rate of molar degeneration, and the absence of fetal anemia. However, there were two maternal complications such as hyperthyroidism and frequent vaginal bleeding without subsequent anemia after integrated examination. Hence, monitoring of both maternal and fetal conditions were done strictly.

Method of termination of molar pregnancy depends on the gestational age and its following comorbid. It is terminated by complete curettage of the uterine cavity in early gestational age. In the second trimester, intra-amniotic injection of rivanol and intravenous oxytocin or cesarean section are still controversial13. Cesarean section is recommended as repeated contraction of uterus may increase the probability of squeezing of the hydatidiform tissue into abdominal cavity, leading to increased risk of pulmonary embolism. Due to the patient’s admission to the hospital had been in active phase of labor and marginal placenta previa, the patient delivered vaginally. Oxytocin was administered following rapid removal of the grape tissue. The uterus contracted well with little bleeding and no obstacle.

Villous vesicular changes in PHM is only few and focal, not as extensive as complete moles. The probability of postpartum persistent trophoblastic disease in PHM is predicted to be 4%, which is much lower than that in CHM. Therefore, chemotherapy is rarely necessitated6. In our case, the pregnant woman was followed up closely in accordance with the principle molar pregnancy follow-up.

Conclusions

A rare case of PHM coexistent with a live fetus with placenta previa was reported in this study. This case was complicated with frequent vaginal bleeding and hyperthyroidism. Under appropriate management, the patient vaginally and prematurely delivered a live fetus. Prompt and regular monitoring of maternal and fetal condition holds an important role.

Ethical approval

This study does not require ethical approval as determined by the institutional and departmental review board.

Consent

Written informed consent was obtained from the patient for the publication of this case report and accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal on request.

Sources of funding

The study did not receive external funding.

Author contribution

D.P.J.S., A.A., and A.D.N. were responsible for the conception and design of the study, interpretation of data, drafting, and revising the article to the final form as submitted. They were also involved in the patient’s care during hospitalization follow-up. A.P. and A.K. was involved in the conception of the design of the study, data interpretation, and editing of the manuscript.

Conflicts of interest disclosure

The authors declare that they have no conflict of interest.

Research registration unique identifying number (UIN)

Registration of research is not applicable in our case.

Guarantors

Dhanny P.J. Santoso, Annisa D. Nugrahani, and Anton Anton.

Provenance and peer review

Not commissioned, externally peer reviewers.