Fetal umbilical vein varix is the dilatation of umbilical vein over 9 mm; its incidence rate has been found to be 1/2300, and it constitutes approximately 4% of umbilical cord malformations. In our case, in the detailed anatomy scan of a 26 year-old patient in the 23rd week of the pregnancy, varicose enlargements were detected in the umbilical vein of the fetus; the diameter of umbilical vein was measured as 10.2 mm. Varicose enlargement with a diameter of 18 mm was found under the connection point of umbilical vein to the abdomen in the fetus. It was observed in the postnatal ultrasound and Doppler ultrasonography examinations carried out in the 7th day that venous structures in the abdomen of the newborn were normal. The prognosis of FIUV is generally fine. In most cases, close sonographic monitoring is considered to be sufficient, and the termination of the pregnancy is not thought to be necessary.
Fetal umbilical vein varix is the aneurysmatic dilatation of umbilical vein, and it constitutes approximately 4% of umbilical cord malformations . FIUV varix is defined as a condition in which the diameter of umbilical vein is above 9 mm or more than 50% larger than the diameter of intrahepatic vein . For a long time, isolated FIUV cases could not be distinguished from other structural or chromosomal abnormalities . However, in the last three decades, approximately 150 isolated FIUV varix cases were defined . FIUV is generally diagnosed in the second and third trimesters. It is sonographically observed as an anechoic cystic dilatation between abdominal wall and inferior part of the liver. FIUV diagnosis can be easily confirmed with the observation of venous vascular enlargement in Color Doppler Ultrasonography. Although the clinical importance of this complication is not clearly determined, there are certain literatures indicating that the disease is related to various abnormalities . Some of the complications which are found to be related to FIUV in the literature are thrombosis, rupture and cardiac insufficiency as a result of increased cardiac preload. The risks of thrombosis and rupture related to the augmentation in fetal blood flow increase in 27th-30th weeks of pregnancy. Moreover, hydrops fetalis, diaphragmatic hernia, fetal anemia, oligohydramnios, hydrocephalus and growth retardation have been reported to be concomitant diseases. There are certain publications in which FIUV is asserted to have negative impacts on the prognosis of pregnancy  ; however, in the recent reports, it has been also stated that neonatal prognosis is much more better than indicated in previous studies , that the patients diagnosed with isolated FIUV varix have completed the pregnancy process without any complication, and that clinical outcomes are quite positive .
A 26 year-old patient, having second pregnancy, did not present any specific feature in her history apart from a prior cesarean delivery. She was referred to our clinic after the observation of a cystic mass in the abdomen of the fetus in the ultrasound examination. In the obstetric examination of the patient, it was found that she had single alive fetus of 23 weeks from her last menstrual period, and that biometric measurements complied with the pregnancy week. In the detailed anatomy scan, varicose enlargements were detected in the umbilical vein of the fetus (figüre 1); the diameter of umbilical vein was measured as 10.2 mm (figure 2). Varicose enlargement with a diameter of 18 mm was found under the connection point of umbilical vein to the abdomen in the fetus (figure 3). Moreover, varicose enlargements were observed in the parailiac veins. Rightward fusiform enlargement was also detected in the fetal cardiac interatrial septum. Other fetal cardiac structures were stated to be normal. Concomitant structural abnormalities were not found in the detailed ultrasound examination. The fetus was diagnosed with fetal umbilical vein varix (FUV) by means of the analysis of the findings. Any complication was not identified in the follow-ups until 32nd week of pregnancy. Fetal growth retardation was observed after 32nd week of the pregnancy. 5 week-intrauterine growth retardation was present in the 39th week of the pregnancy from her last menstrual period. The patient underwent cesarean operation. It was observed in the ultrasound and Doppler ultrasonography examinations carried out in the 7th day after the delivery that venous structures in the abdomen of the newborn were normal (figure 4). Cardiac interatrial septum was also found to be normal.
Fetal intra-abdominal umbilical vein varix (FIUV) is defined as the dilatation of the umbilical vein, and it is typically seen in the intra-abdominal section. The etiology of FIUV is not clearly known. FIUV is a rare complication whose incidence rate has been found to be 1/2300 in a study  ; it constitutes 4% of approximately all umbilical cord malformations. FIUV is diagnosed 27th gestational week in average; it is quite rare to see the disease before 22nd gestational week. Varicose enlargement is most commonly observed inside of the umbilical cord rather than intra-abdominal section of the umbilical vein. Extrahepatic settlement of intra-abdominal umbilical vein varix is much more common than intrahepatic settlements. Intra-abdominal extrahepatic part of the vein is the least fed section .
The diameter of umbilical vein (UV) shows a linear increase during pregnancy, and it reaches 8 mm at term while it has been 3 mm in the 15th week . FIUV varix is defined as a condition in which the diameter of umbilical vein is above 9 mm or more than 50% larger than the diameter of intrahepatic vein . The pathological finding detected in most of the cases is the weakening and dilatation of umbilical vein wall situated in a closer section to the frontal wall of the abdomen. Typical sonographic image of FIUV is seen as non-echoic cystic dilatation between abdominal wall and inferior section of the liver. The diagnosis is confirmed by the identification of the existence of venous flow in the lumen via Color Duppler ultrasonography  . In our case, the diameter of umbilical vein was measured as 10.2 mm and cystic dilatation with a diameter of 18 mm was found under the connection point of umbilical cord to the abdomen in the fetus.
The disease is generally diagnosed in second or third trimesters, mostly between 21st and 34th weeks. Moreover, other cystic abdominal structures such as fetal gallbladder, choledochal cyst, mesenteric cyst, urachal cyst, ovarian cyst, dilated intestine and genitourinary structures should also be taken into consideration in the diagnosis .
Although pregnancy prognosis is stated to be generally good in those patients , it is also indicated that FIUV findings may be used as an indicator for abnormality scan because of the risk of concomitant fetal abnormalities. FIUV has been associated to 44% of fetal death and 12% of karyotype abnormalities (trisomy 21, 18, 9 and triploidy 69 XXX). Structural malformations and hydrops fetalis were also observed in more than 35% of the cases . Associated anomaly of 31% and chromosomal anomaly of 9.9% were found in the case series analyzed by Fung and his colleagues. Perinatal loss occurred in 13% of those cases while normal obstetric outcomes were obtained in 59% of the cases .
Complication development incidence increases significantly in case FIUV is diagnosed before 26th week of pregnancy . In the literature, most common complications in the patients diagnosed with FIUV may be listed as varix rupture, thrombosis, cardiac insufficiency, compression of the umbilical artery and other veins . Our patient was monitored until the 39th week of pregnancy, and no another complication apart from intrauterine growth retardation was observed, similar to the cases in the literature .
In the study carried out by Mankuta et al , FIUV was detected in 28 pregnant women out of 65 000; fetal death and abnormality was observed in none of the cases monitored. In the last similar literature series, it has been indicated that isolated FIUV does not increase fetal mortality rate   while certain cases in which fetal deaths have been observed due to varix rupture and thrombosis have also been reported   . Fetal mortality rates related to the varix rupture and thrombosis have been reported as 50% and 80% respectively. Since there is an increase in fetal blood flow in 27th and 30th weeks of pregnancy, fetal losses related to rupture and thrombosis in UVA are most commonly seen in those weeks . In the literature searches, approximately 150 isolated FIUV varix cases have been identified; intrauterine death was observed in 7 cases . In a different study, unexplained intrauterine deaths were reported in 8.1% of 62 isolated UVA cases between 29th and 38th weeks of pregnancy .
Two mechanisms which explain intrauterine fetal deaths related to FIUV have been defined: in the first mechanism, thrombosis occurs in the dilated section of umbilical cord; it permeates in fetal circulation and results in sudden infant death. In the second mechanism, deaths arise from pericardial effusion, edema and hydrops, which are the signs of decompensation after cardiac insufficiency resulted from volume surplus   .
According to the data in the literature, since FIUV is accompanied by increased associated fetal anomaly risk, detailed ultrasonographic scan should be primarily advised subsequent to the diagnosis of FIUV . In addition, fetal echocardiography is also recommended in the cases of isolated FIUV varix . Consultation should be recommended for the mothers having isolated FIUV varix in terms of possible obstetric and genetic outcomes; in case of other concomitant abnormalities, amniocentesis should also be suggested .
In the cases of isolated FIUV, it is sufficient to monitor fetal growth by means of serial ultrasonographic follow-ups during pregnancy . It is recommended that color Doppler USG follow-ups are implemented at intervals of 2 weeks in fetal monitoring, and that the sizes of varicose vein, the clot formation and the development of hydrops are monitored. Close follow-ups of the fetus are advised after 32nd week of pregnancy in the cases in which intrauterine growth retardation and turbulent flow are observed. On the other hand, delivery is recommended in case of the development of hydrops findings or the clot formation in varicose vein .
In conclusion, the prognosis of FIUV is generally good unless associated fetal anomalies are observed in spite of diagnosis in early pregnancy week. In most of the cases, close sonographic monitoring is sufficient until the term, and the termination of pregnancy is not required. In fetal follow-up process, the physicians should be careful about certain situations which may occur as a result of FIUV such as hydrops, oligohydroamniosis, and intrauterine growth retardation. The timing of delivery may vary according to the progressing complications.
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