Abstract: Background and Objectives: The secondary yolk sac is the extraembryonic structure, translucent, cyst like within the gestational sac (1).
It is seen the chorionic cavity from 5th week to 11 week 6days of menstrual age at the latest(2). It acts as primary source of exchange between embryo and mother before the establishment of placental circulation during organogenesis (3). Yolk sac functions like, nutritive, endocrine, metabolic, secretory, excretory functions (4).our study is conducted to evaluate the size of yolk sac for predicting early pregnancy outcome.
Methods: In this study 100 women attending their first trimester antenatal visit were included. Women with 5 week and 10 weeks of gestation were evaluated for YSD, MSD, CRL by transvaginal ultrasound. Their regular follow up done, routine investigations done, Nuchal translulescency scan done between 11 week to 13 week 6 days, and TIFFA scan for fetal anomaly done between 18 weeks to 24 weeks. Pregnancy without any complications labelled normal and those with abortion, increased NT and fetal anomaly were labelled as abnormal
Results: There was a significant positive correlation between Yolk Sac Diameter, Crown Rump Length, Gestational Sac and Gestational Age A Normal range of YSD Is established based on normal outcome of each Gestational week YSD >2SD above or below the mean were considered as abnormal YSD(5). With Sensitivity of 90.9% Specificity 96.48% PPV- 55.56%. And NPV -90.96%
Conclusion: We Can Conclude from the present study that measurement of secondary yolk sac diameter between 6th to 10th week of gestation can be used as a valuable tool to predict early pregnancy outcome, even before the detection of embryo. This in turn helps in counseling the parents regarding the risk of miscarriage and need for follow up ultrasound examinations.
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