Live‐born diploid fetus complicated with partial molar pregnancy presenting with pre‐eclampsia, maternal anemia, and seemingly huge placenta: A rare case of confined placental mosaicism and literature review

Abstract

A partial molar pregnancy almost always ends in miscarriage due to a triploid fetus. We describe a rare case of a singleton, partial molar pregnancy with a seemingly huge placenta, which continued to delivery of a live-born diploid baby. A 27-year-old primigravida suffered from severe pre-eclampsia and progressive anemia. The uterus was enormously enlarged for the gestational age. A cesarean section was performed because of deterioration of maternal status at 25 weeks' gestation, when more than 3000 mL blood spouted concurrently with the delivery of the placenta. The histological examination showed congestion in the decidua, which indicated disturbance of maternal venous return from the intervillous space. The chromosome complement of the placenta and the neonate were 69,XXX and 46,XX, respectively. We also reviewed all published cases of a singleton, partial molar pregnancy. A literature search yielded 18 cases of a singleton, diploid fetus with partial molar pregnancy. The mean gestational age at delivery was 24.5 ± 6.2 weeks, and fetuses survived outside the uterus in only four cases (22.2%). Intriguingly, previous reports numbered 10 cases with diploid placenta as well as five cases with no karyotyping of the placenta, indicating that they may have included a complete mole in a twin pregnancy or placental mesenchymal dysplasia. In conclusion, this was the first case of placentomegaly that presented manifestations of excessive abdominal distension and maternal severe anemia, and the second case of a singleton, partial molar pregnancy confirmed by chromosome analysis resulting in a diploid living baby.

A partial molar pregnancy associated with a fetus with intrauterine growth restriction delivered at 31 weeks: a case report

“…An increased incidence could be explained by the greater use of assistive reproductive techniques [8]. There are three types of molar pregnancy with coexisting normal live fetus: the most frequent case is a twin pregnancy with one normal fetus having a normal placenta and another complete mole; the second type is a twin pregnancy with regular fetus and placenta and another partial mole [9]; the third and most uncommon occurrence reported only 19 times in the literature is a singleton normal fetus with partial molar placenta, which is similar to our case [5]. The diagnosis of molar pregnancy with coexisting fetus is difficult.…”

“…Interruption of pregnancy is common owing to congenital anomalies like triploidy of the fetuses and severe intrauterine fetal growth restriction due to limited normal functional placental circulation. If the pregnancy does not stop, management of molar pregnancies with an apparently normal fetus remains challenging [5, 14]. The woman must be counseled regarding the maternal and fetal complications: late abortion, vaginal bleeding, mal presentations, preterm labor, persistent gestational trophoblastic disease, severe anemia in the fetus, hyperthyroidism, hypertensive disorders of pregnancy, pulmonary edema, and thromboembolic phenomena [15, 16].…”

“…However, partial moles are often misdiagnosed as an incomplete or missed abortion of the first trimester. In less than 25% of cases, pregnancy with a partial mole and a single normal fetus evolves to a viable fetus: in such cases the diagnosis can be suspected or misunderstood [5] and the management is a challenge for potential maternal and fetal complications. Here we report a rare case of misdiagnosed partial molar pregnancy in which a normal-appearing male fetus with diploid karyotype was delivered at 31 weeks of gestation.…”

Conservative Management, Follow-up and Perinatal Outcomes After Gestational Trophoblastic Disease with Coexistent Normal Fetus: Case Report

“…In such cases, there is usually a clear distinction, both sonographically and pathologically, between the molar and non-molar regions of the placenta [18]. A PubMed research about the third type of molar pregnancy has been reported a few times during the period between 1975 to 2018 finding 7 to 13 cases in the medical literature [8,14], and it has been documented to be more in female fetuses with female:male of approximately 3.5:1 [12]. In this case, a preterm baby girl was delivered with no physical malformations during ultrasound examinations, and a normal karyotype 46XX.…”

“…Kawasaki and cols reported a literature search, which yielded 18 cases of a singleton, diploid fetus with partial molar pregnancy. The mean gestational age at delivery was 24.5 +/-6.2 weeks, and fetuses survived outside the uterus in only four cases (22.2%) [12]. Management of molar changes associated with normal appearing fetus still remains challenging, with a high risk for both mother and fetus [5].…”