Abstract:A very large yolk sac may exist in normal pregnancy. When embryonic heartbeats exist, the poor quality and early regression of a yolk sac are more specific than the large size of a yolk sac in predicting pregnancy loss. When an embryo is undetectable, a relatively large yolk sac, even of normal shape, may be an indicator of miscarriage.
“…Sequential appearance of a yolk sac, embryonic heartbeat, and an amniotic cavity is essential for normal pregnancy [5]. The yolk sac is seen in all pregnancies from 5 weeks' gestation onwards, when the gestational sac exceeds 11 mm in diameter [13].…”
Section: Discussionmentioning
confidence: 99%
“…The diameter of a yolk sac is usually 3-4 mm and increases in size up to the 10 th or 11 th week of gestation [3]. It has been hypothesized that abnormal sonographic findings related to the size, shape and internal structure of a yolk sac can be used to predict gestational outcome [3][4][5][6][7]. It has been well established that an abnormally large yolk sac correlates with early pregnancy failure [4,6,7].…”
Section: Introductionmentioning
confidence: 99%
“…On the other hand, studies focusing on the shape or internal structure of the yolk sac have yielded conflicting results. Some studies suggest that irregular yolk sac shape and echogenic yolk sac can be associated with fetal death or abnormalities [5,[8][9][10]. In contrast, some authors claimed that a pregnancy could have a completely Fig 2. a-d.…”
Aims: The present study aimed to determine whether yolk sacs with abnormal sonographic appearance are associated with adverse perinatal outcomes in both early and late gestation. Matherial and methods: A total of 305 viable singleton pregnancies with gestational age of 6 to 9 weeks were prospectively evaluated with respect to perinatal outcomes and sonographic characteristics of the yolk sacs. Results: An abnormal yolk sac was found in 66 pregnancies. In pregnancies with enlarged yolk sacs a miscarriage occurred in 37.5% of cases (3/8). The pregnancies with a yolk sac diameter ≥ 5 mm had a significantly higher risk of miscarriage (p = 0.005). The risk of miscarriage was statistically similar between the pregnancies with regular and those with irregular yolk sacs (p = 0.73). Miscarriage occurred in 3.8% of pregnancies with irregular yolk sacs (2/52) and none of pregnancies with echogenic yolk sacs (0/6). Adverse perinatal outcomes were not associated with either irregular or echogenic yolk sacs. Conclusions: An enlarged yolk sac visualized before the 7th week of gestation is strongly associated with a significantly increased risk for spontaneous miscarriage. The presence of an echogenic or irregular yolk sac appears to be unrelated to adverse perinatal outcome.
“…Sequential appearance of a yolk sac, embryonic heartbeat, and an amniotic cavity is essential for normal pregnancy [5]. The yolk sac is seen in all pregnancies from 5 weeks' gestation onwards, when the gestational sac exceeds 11 mm in diameter [13].…”
Section: Discussionmentioning
confidence: 99%
“…The diameter of a yolk sac is usually 3-4 mm and increases in size up to the 10 th or 11 th week of gestation [3]. It has been hypothesized that abnormal sonographic findings related to the size, shape and internal structure of a yolk sac can be used to predict gestational outcome [3][4][5][6][7]. It has been well established that an abnormally large yolk sac correlates with early pregnancy failure [4,6,7].…”
Section: Introductionmentioning
confidence: 99%
“…On the other hand, studies focusing on the shape or internal structure of the yolk sac have yielded conflicting results. Some studies suggest that irregular yolk sac shape and echogenic yolk sac can be associated with fetal death or abnormalities [5,[8][9][10]. In contrast, some authors claimed that a pregnancy could have a completely Fig 2. a-d.…”
Aims: The present study aimed to determine whether yolk sacs with abnormal sonographic appearance are associated with adverse perinatal outcomes in both early and late gestation. Matherial and methods: A total of 305 viable singleton pregnancies with gestational age of 6 to 9 weeks were prospectively evaluated with respect to perinatal outcomes and sonographic characteristics of the yolk sacs. Results: An abnormal yolk sac was found in 66 pregnancies. In pregnancies with enlarged yolk sacs a miscarriage occurred in 37.5% of cases (3/8). The pregnancies with a yolk sac diameter ≥ 5 mm had a significantly higher risk of miscarriage (p = 0.005). The risk of miscarriage was statistically similar between the pregnancies with regular and those with irregular yolk sacs (p = 0.73). Miscarriage occurred in 3.8% of pregnancies with irregular yolk sacs (2/52) and none of pregnancies with echogenic yolk sacs (0/6). Adverse perinatal outcomes were not associated with either irregular or echogenic yolk sacs. Conclusions: An enlarged yolk sac visualized before the 7th week of gestation is strongly associated with a significantly increased risk for spontaneous miscarriage. The presence of an echogenic or irregular yolk sac appears to be unrelated to adverse perinatal outcome.
“…Cho et al (4) have reported that, in the presence of a heart beating embryo, with irregular or hydropic YS, or even an early disappearance of the YS, the gestation could result in miscarriage.…”
Section: Inmentioning
confidence: 99%
“…During the first gestational trimester, some parameters, such as small diameter of the gestational sac (3) and absence, or even YS deformity (4) , were observed at 2DUS and associated with a poor gestational prognosis. Additionally 2DUS images have demonstrated that the YS diameter exponentially increases in the period between the 5th and the 11th weeks (5) , and then presents a significant decrease, as the embryo develops.…”
). Mean, median, standard deviation, maximum and minimum values for yolk sac volume were calculated for each gestational age. RESULTS: A poor correlation was observed between yolk sac volume (YSV) and gestational age (GA).
AbstractResumo
At the point of early miscarriage diagnosis, a yolk sac larger than 5 mm suggests an abnormal fetal karyotype, whereas an absent embryo indicates a normal fetal karyotype.
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