COMPARISON OF INTRAUTERINE HEMATOLOGIC AND BIOCHEMICAL VALUES BETWEEN TWIN PAIRS WITH AND WITHOUT STUCK TWIN SYNDROME

OBJECTIVE: Our purpose was to compare hematologic and biochemical values in cordocentesis specimens from twin pairs with and without stuck twin syndrome. STUDY DESIGN: Cordocentesis was performed on 38 twin pairs. Assignment to the stuck twin syndrome group (n = 8) was based on ultrasonographic findings of discordant size and amniotic fluid volume, concordant gender, and a single placenta. A receiver-operator characteristic curve was constructed with the use of intertwin hemoglobin differences. For the stuck twin syndrome group regression analysis of gestational age and intertwin hemoglobin difference was done. RESULTS: We found significant Co = 0.03) intertwin differences in hemoglobin between the stuck twin syndrome group (mean 5.35 gm/dl, range 0.5 to 15.4 gm/dl) and the comparison group (mean 0.10 gm/dl, range 0.0 to 2.4 gm/dl). A nearly significant relationship between gestational age and intertwin hemoglobin difference was noted in the stuck twin syndrome group. When the hemoglobin difference was >2.4 gm/dl, all cases had stuck twin syndrome (sensitivity = 50%, specificity = 100%, positive predictive value = 100%, negative predictive value = 91%). In the stuck twin syndrome group there was a trend toward larger intertwin differences in albumin and total protein. Intertwin blood gas values between the groups did not differ, but the average Po-2 was lower when the smaller twins of the two groups were compared. CONCLUSION: An intertwin difference in hemoglobin >2.4 gm/dl is consistent with stuck twin syndrome. Large intertwin hemoglobin differences and imbalances in albumin and total protein may be seen in stuck twin syndrome.