Placental anomalies have been associated with a higher incidence of maternal and fetal morbidity and mortality. Succenturiate placenta is a rare morphological abnormality of the placenta in which there are one or more accessory lobes connected to the main placental mass by blood vessels. We report the case of a 23-year-old woman who was referred to the prenatal diagnosis center at 20 weeks of gestation due to early fetal growth restriction. This pregnancy was also complicated by preeclampsia and placental abruption. Postpartum, there was an incidental finding of succenturiate placental lobe. The diagnosis of succenturiate placenta in the prenatal period is essential in order to allow an adequate pregnancy follow-up, as well as to avoid pre- and postnatal complications.
Anomaliile placentei au fost asociate cu o incidenţă mai mare a morbidităţii şi mortalităţii materne şi fetale. Placenta cu lob placentar accesor este o anomalie morfologică rară a placentei în care există unul sau mai mulţi lobi accesorii legaţi de masa placentară principală prin vase de sânge. Raportăm cazul unei femei în vârstă de 23 de ani, care a fost trimisă la centrul de diagnostic prenatal la 20 de săptămâni de gestaţie din cauza restricţiei precoce a creşterii fetale. Această sarcină a fost complicată cu preeclampsie şi decolarea placentei. După naştere, a existat o descoperire incidentală a lobului accesor. Diagnosticul placentei cu lob accesor în perioada prenatală este esenţial pentru a permite o urmărire adecvată a sarcinii, precum şi pentru a evita complicaţiile pre- şi postnatale.
Pregnant women with placental anomalies have a higher incidence of perinatal death. Succenturiate placenta is a morphological anomaly in which one or more small accessory lobes develop in the membranes with vascular connections of fetal origin, on the periphery of the main placental bed(1). It has an incidence of approximately 0.16 to 4.3%. This rare obstetric complication may endanger both the mother’s and the fetus’ life(2).
The diagnosis of this anomaly usually occurs after childbirth, as there are only few cases in which prenatal diagnosis through ultrasound is performed(3).
A 23-year-old healthy primigravida Caucasian woman was referred to the prenatal diagnosis center at the University Hospital Center of Algarve – Faro, Portugal, due to early fetal growth restriction (FGR), diagnosed at 20 weeks of gestation. Additionally, a placental accessory cotyledon in the posterior wall was described, while the main placental bed was located in the anterior wall with marginal insertion of the cord.
Amniocentesis was proposed, and amniotic fluid was obtained for polymerase chain reaction (PCR), microarray and skeletal dysplasia panel. At 24 weeks of gestation, a fetal echocardiogram revealed a slight disproportion of the great vessels, with no other relevant changes. All other exams were normal.
Ultrasound reassessment at 25 weeks estimated the fetal weight at percentile (P) 1, middle cerebral artery flowmetry at P 1 and cerebroplacental quotient at P 0.2, which led to the weekly surveillance of pregnancy. Doppler study of the umbilical artery, as well as of the ductus venosus, was normal.
At 28 weeks of gestation, a new ultrasonography showed an absent diastolic flow in the umbilical artery, in addition to the flowmetric alterations previously described. Simultaneously, an increase in the blood pressure was noticed, with associated proteinuria (proteinuria in 24 hours urine – 472 mg), therefore the diagnosis of preeclampsia was assumed. She was admitted in the obstetrics service ward for maternal and fetal surveillance. Steroids for fetal lung maturation were instituted. At 31 weeks of gestation, a 5.2x4.3x6.2 cm measuring mass was identified on ultrasound assessment, originating from the posterior lobe of the placenta (Figure 1). Close monitoring was performed and, two days later, ultrasound reassessment allowed the visualization of anechogenic zones within the new placental mass described, suggesting a placental hematoma. Due to the suspicion of placental detachment, an emergent caesarean was performed. The surgical intervention was uneventful.
A 964 g newborn with an Apgar score of 4/6/6 at 1, 5 and 10 minutes was delivered. The neonatal period was complicated by respiratory distress syndrome, which led to the admission in the Neonatal Intensive Care Unit.
The anatomopathological study of the placenta revealed a succenturiate placenta, with a second accessory lobe (Figure 2), weighing 196.9 g and measuring 21.5 x 10.5 cm, with a variable thickness between 0.3 cm and 2.7 cm, and advanced maturation for gestational age. The umbilical cord was 34 cm long and 2 cm in diameter, with three vessels and a marginal insertion.
Placental anomalies are an uncommon finding in obstetrics, in particular the succenturiate placental lobe. Thus, the succenturiate placenta appears as a rare entity, more often found in pregnant women over 35 years of age or in pregnancies obtained through in vitro fertilization. It is not usually detected by ultrasound(2,4-6).
One of the main challenges in the diagnosis of this entity is the identification of the posterior lobes, as the ultrasound waves do not go beyond the fetal body(1,5). Several studies have established the relevance of color Doppler in the obstetric ultrasound examination, as it allows the study of the placenta, the insertion of the umbilical cord and the presence of abnormal vessels between placental lobes(1,7).
In this clinical case, despite the identification of a posterior accessory lobe in the ultrasound evaluations, the diagnosis of a succenturiate placenta was only possible after delivery, which is the most common timing for the diagnosis, according to the literature(3,7). The relevance of the ultrasound diagnosis of this entity arises from the potentially associated complications(7).
During pregnancy, Ma et al. reported that the succenturiate placenta is related to a higher incidence of preeclampsia, FGR, increased risk of prematurity, premature abruption of normally inserted placenta and caesarean delivery, all of which were verified in the clinical case described above(8). Other studies have described low birth weight, perinatal death, premature birth and emergency caesarean as the main complications associated with the succenturiate lobe(9-11).
Abnormal insertion of the umbilical cord is also characteristic of these pathologies. It is often associated with the existence of a succenturiate placenta, namely the velamentous insertion (50% of cases) or the marginal insertion of the umbilical cord, as found in the presented case(7).
Regarding placental detachment, despite its occurrence in the case presented, Kumari et al. reported that the risk is low in the case of a succenturiate placenta, and such complication is not commonly found in the literature(2).
Although an emergent caesarean section was performed in the present case, it is important to mention the potential complications of the placenta during labor, as there is an increased risk of rupture of the vessels connecting the main placental bed with the succenturiate lobe, which can lead to fetal death, especially if these vessels originate a vasa praevia(1,6-8). Therefore, the confirmation of the path of these vessels by ultrasound is essential, particularly when the existence of an accessory lobe is verified, and the presence of a vasa praevia should always be ruled out(6).
Regarding the complications of a succenturiate placenta during the third stage of labor and postpartum, placental retention may occur and, consequently, primary or secondary postpartum hemorrhage and sepsis, increasing maternal morbidity(1,7). A careful evaluation of the cotyledons after placental delivery is essential to prevent such complication and, at the same time, it will allow the diagnosis of succenturiate placenta in case it had not been done in the prenatal period(7).
In the clinical case presented, clinical and ultrasound surveillance throughout pregnancy played a key role in the diagnosis and follow-up of placental structural abnormalities and FGR, as it allowed the identification of the placental detachment and motivated the successful delivery at 31 weeks and 6 days.
Succenturiate placenta can be diagnosed antenatally by ultrasonography and can be a cause of antepartum or peripartum hemorrhage, leading to increased maternal and perinatal morbidity and mortality. The early diagnosis by ultrasound can change the course and prognosis of the patient who undergoes a pregnancy with this placental alteration.
Conflict of interests: The authors declare no conflict of interests.
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