Yolk Sac Diameter As a Predictor of Pregnancy Outcome

Yolk sac diameter as a predictor of pregnancy outcome Synopsis

Done by : Dr. Keerthana Anand . Guide: Dr. Shakila Shetty

RAJIV GANDHI UNIVERSITY OF HEALTH SCIENCES KARNATAKA, BANGALORE

Annexure-II

PROFORMA FOR REGISTRATION OF SUBJECTS FOR DISSERTATION

(To be submitted in duplicate)

1. Name of the candidate and

Address : Dr. Keerthana Anand

#245, 2nd main road, 7th block,

Jayanagar, Bangalore 560070

2. Residential address : C/o Mr.M.A.Somashekar

#245, 2nd main road, 7th block,

Jayanagar, Bangalore 560070

3. Name of the institution : M.S. Ramaiah Medical college

4. Course Of Study And Subject : M.S. Obstetrics and Gynaecology

5. Date Of Admission To The Course : 30th May 2011

6. Title Of The Topic : Yolk sac diameter as a

predictor of pregnancy outcome

7. Brief Resume Of The Intended Work

a. Need For the Study :

The secondary yolk sac is the first extraembryonic structure that can be detected with

transvaginal sonography (TVS) in the chorionic cavity and can be seen from the 5th to

the 12th week menstrual age, at the latest.

During organogenesis and before placental circulation is established, yolk sac is the primary source of exchange between the embryo and the mother. Yolk sac has nutritive, endocrine, metabolic, immunologic, secretory , excretory and hematopoietic functions.

Many studies on the prognostic significance of the Yolk sac for the pregnancy outcome have been performed with conventional sonography and more recently with TVS. The results are conflicting.

Thus further studies on the measurement of yolk sac size and its association with normal and abnormal pregnancy outcome, could help as an early predictor of pregnancy outcome. b. Review Of Literature:

In a study conducted by Daniel J et al at the health sciences center in Winnipeg, Canada it was found that a yolk sac diameter more than 2 SD above the mean when compared with the mean gestational sac diameter allowed prediction of an abnormal pregnancy outcome with sensitivity of 15.6 % and specificity of 97.4 % and positive predictive value of 60%.

Yolk sac diameter more than 2SD below the mean allowed prediction of an abnormal outcome with sensitivity of 15.5 % , specificity of 95.3% and a positive predictive value of 44.4% 1

In another study by C.Stampone et al, a Yolk sac with abnormal size ( above and below 2 standard errors of regression ) was statistically significant by Fisher’s exact test ( p< 0.001) in spontaneous abortion, with a sensitivity of 68.7%, a specificity of 99%, a positive predictive value of 91.6% and a negative value of 95.2%.2

It is recommended that patients at risk of poor pregnancy outcome should have a routine Trans vaginal scan before 12 weeks of gestation to assess their yolk sac and those with an abnormal yolk sac should be followed up closely to exclude fetal anomalies before 24 weeks gestation 3

It has also been proved in a study conducted by Duru NK et al in the department of OBG, Gulhane school of medicine, Ankara Turkey, that the secondary yolk sac evaluation is a valuable tool to predict pregnancy outcome.4

c. Aim

To evaluate the size of secondary yolk sac as a predictor of pregnancy outcome.

d. Objectives:  To study the biometry of yolk sac and its co relation with menstrual age, crown rump length and mean gestational sac diameter in early pregnancy ( less than 10 weeks )

 To assess the predictive value of abnormal yolk sac size at endovaginal ultrasound for abnormal pregnancy outcome

8. Materials and Methods:

a. Source Of Data :

Patients attending obstetric OPD at M.S Ramaiah Hospital

b. Method of collection Of data :

Sample size: 200

This was estimated based on the study titled YOLK SAC DIAMETER AND SHAPE AT ENDOVAGINAL ULTRASOUND : PREDICTORS OF PREGNANCY OUTCOME IN FIRST TRIMESTER by Daniel J. Lindsay et al in the Department of Radiology, Health sciences centre, Winnipeg, Canada1 In the above study it was revealed that out of 486 patients 159 (32.7 %) had abnormal outcome in 1st trimester. Sample size for this study has been estimated based on above findings with a relative precision of 20% and confidence level of 95%. The estimated sample size worked out to be 195. Thus, it is proposed to include 200 antenatal women who are registering before 10 wks of gestational age.

Informed consent will be taken from the antenatal women for the performance of trans vaginal scan, which is being done routinely in the first trimester. Yolk sac diameter, crown rump length and gestational sac diameter will be measured.

They would be followed up till 24 wks of gestation and considered as normal pregnancy outcome if pregnancy continued beyond 24 wks and abnormal outcome if they have spontaneous abortion or demonstrable fetal anomalies. c. Statistical analysis

All the quantitative parameters such as yolk sac diameter, gestational age, CRL, Mean gestational sac diameter, age and parity of women etc will be described in terms of descriptive statistics such as mean and standard deviation. Upper and lower 95% confidence limits will also be estimated. Appropriate graphical presentation will be carried out to plot the yolk sac diameter with mean +/- 2SD based on women with normal pregnancy outcome. Bivariate co relation will be estimated between different factors such as Yolk sac diameter v/s Gestational age, Yolk sac diameter v/s Crown rump length, Yolk Sac diameter v/s Mean gestational sac diameter. To test for difference in Yolk sac diameter between abnormal and normal outcome t-test/non parametric tests of significance will be employed.

Inclusion Criteria:

Pregnant women at menstrual age less than 10 weeks

Exclusion Criteria:

1. Molar pregnancy 2. Women with structural anomalies of uterus and cervix 3. Women with known endocrine disorder causing abnormal pregnancy outcome

d. Does the study require any investigation or intervention to be conducted on patients or other humans or animals?

Yes, Trans vaginal ultrasound at first trimester. e. Has ethical clearance been obtained from your institution?

9. Duration of study : Oct 2011 to July 2013

10. List of references:

1. Lindsay .D.J , Lovett I.S, Lyons E.A, Levi .C.S., yolk sac diameter and shape at endovaginal US: predictors of pregnancy outcome in the first trimester, Radiology 1992; 183: 115-118

2. Stampone C, Nictoria M, Muttinelli C, Cosmi.E.V. Transvaginal sonography of the yolk sac in normal and abnormal pregnancy. J Clin Ultrasound 1996; 24: 3-9

3. Chama C.M.,Marupa J.Y., Obed J.Y, the value of the secondary yolk sac in predicting pregnancy outcome, J Obstet Gynecol 2005; 25(3):245-7

4. Kucuk T, Duru N.K., Yenen MC, Ergun A, Baser I, yolk sac size and shape as predictors of poor pregnancy outcome, J Perinat med, 1999:27(4)316-20.

5. Cepni I, bese T, Ocal P, Budak E, Idil M, Aksu M.F., significance of yolk sac ,measurement with vaginal sonography in the first trimester in the prediction of pregnancy outcome, Acta Obstet Gynecol Scand 1997; 76(10) : 969-72

6. Papaioannou G.I, Syngelaki A, Poon L.C.Y, Ross J.A , normal ranges of embryonic length, embryonic heart rate, gestational sac diameter and yolk sac diameter at 6 -1 0 weeks, fetal Diagn Ther 2010;28:207-219. 11. Signature of the candidate:

(Dr. Keerthana Anand)

12. Remarks of the guide:

The yolk sac has nutritive, endocrine, metabolic, immunologic, secretory, excretory and haemopoetic functions. The purpose of this study are to study the biometry of the yolk sac and its relation with menstrual age, crown rump length and mean gestational sac diameter in early pregnancy and to assess the predictive value of abnormal yolk sac size for abnormal pregnancy outcome.

13. Name and designations of guides and the Head of Department.

a. Guide :

Dr. S.Shakila Shetty

Senior Professor and Unit Head, dept Of O.B.G

b. Signature :

c. Head of Department :

Dr. Uma Devi K Senior Professor and H.O.D dept. of O.B.G

d. Signature:

14. Remarks Of the Chairman and principal

a. Signature :