Timing of the onset of weight discordance in pathologic monochorionic twin pregnancies.

Abstract

PURPOSE: Monochorionic twins (MC) have twofold higher mortality than dichorionic twins (DC) and fourfold higher when compared to singletons. We analyzed the development of weight discordance and the average time of diagnosis/morbidity in MC.METHODS: Retrospective analysis of the intertwin weight discordance during pregnancy in Twin-Twin Transfusion Syndrome (TTTS) and Selective Intrauterine Growth Retardation (sIUGR), using a linear mixed model and single-factor analysis of variance in a cohort of MC at our institution. RESULTS: In a cohort of 143 MC the development of the intertwin weight difference varies significantly between uncomplicated and pathologic MC (P<0,001). An intertwin weight difference is detectable starting with the 16th weeks’ of gestation, however, the first diagnosis is routinely made in the 21 weeks’ gestation (20.6 ± 3.9 TTTS, 19.6 ± 3.4 sIUGR). Compared to concordant MC, both TTTS and sIUGR had increased mortality with higher rates of intrauterine fetal demise (18.2% vs. 7.7%; P=0.243) and antenatal corticosteroids (85,7% vs. 65,2%). Delivered 2-3 weeks earlier, pathologic twins had a lower birth weight, lower APGAR and pH values, and a higher demand for neonatal intensive care for longer periods. Artificial reproduction techniques resulted in a 3.6-fold increased risk of developing TTTS (38.4% vs. 21.9%, P = 0.061) and sIUGR (30.8% vs. 21.9%, P=0.061).CONCLUSIONS: The mortality and morbidity in MC highly correlates with the stage and time of the initial diagnosis. Expediting diagnosis and treatment, starting with the 16th week of gestation could arguably decrease intrauterine fetal demise, neurological morbidity, and prematurity.