Fax +41 61 306 12 34 E-Mail karger@karger.ch www.karger.com Original Article Gynecol Obstet Invest 2006;61:80–86 DOI: 10.1159/000088933 Ultrasonic Morphological Characteristics of Yolk Sac in Pregnancy Complicated with Type-1 Diabetes mellitus Marina Ivaniševic ´ Josip Djelmiš Dubravko Jalsovec Danko Bljajic Department of Obstetrics and Gynecology, State Referral Center for Diabetes in Pregnancy, School of Medicine, Zagreb, Croatia DM women was statistically significantly larger after 6 weeks of gestation and the HbA1c levels were 1 6% when compared to the YS dimensions in the group with HbA1c concentrations of ! 6%. Conclusion: A gross change in YS size may indicate or reflect significant dysfunction of the maternofetal transport system in early pregnancy which is complicated with type-1 DM. Copyright © 2006 S. Karger AG, Basel Introduction In normal pregnancy, the secondary yolk sac (YS) is the first embryonic structure visualized ultrasonically within the gestational sac. In relation to its morphological development, the secondary YS can be visualized be- tween 5 and 12 weeks of gestational age (GA). It appears as a circular anechoic sac that lies between the inner am- niotic sac and the surrounding chorionic membrane. Along with crown-rump length (CRL), the size (diameter) of the embryonic structure such as gestational sac and secondary YS may have prognostic value for embryonic development. It is important to know that using ultra- sound it is not possible to visualize the primary YS which is formed at approximately 23 days of gestation. With formation of the extraembryonic celom, the primary YS is pinched off and the secondary YS is formed at approx- Key Words Yolk sac  Early pregnancy  Ultrasound  Diabetes mellitus, type-1 Abstract Background/Aims: In pregnancy complicated with type- 1 diabetes mellitus (DM), information on the predictive value of yolk sac (YS) measurement and YS morphology on outcome has been scant. The aim of this study was to compare the size and shape of the YS using transvag- inal sonography (TVS) in normal pregnancies and those complicated with well-regulated type-1 DM. Methods: Sixty healthy pregnant women and 60 pregnant women with type-1 DM underwent TVS. The correlation coeffi- cients between YS and gestational age (GA), YS and crown-rump length (CRL), and YS and human chorionic gonadotropin (HCG) were calculated. Statistical analysis showed that the difference between the YS diameters for each gestational week among the groups studied was highly statistically significant. Statistical analysis of the results was performed with SPSS 10 software. Results: A highly statistically positive correlation was found be- tween YS diameter and GA, CRL and HCG levels for both groups studied. The YS diameter in type-1 DM pregnan- cies was statistically significantly larger for GA than that of healthy pregnant women. The YS diameter in type-1 Received: January 17, 2005 Accepted: March 20, 2005 Published online: October 13, 2005 Marina Ivaniševic ´ Department of Obstetrics and Gynecology State Referral Center for Diabetes in Pregnancy, School of Medicine Petrova 13, HR–10000 Zagreb (Croatia) Tel./Fax +385 1 4606740, E-Mail josip.djelmis@zg.hinet.hr © 2006 S. Karger AG, Basel 0378–7346/06/0612–0080$23.50/0 Accessible online at: www.karger.com/goi