579 Mid-trimester cervical shortening and its association with adverse neonatal outcomes in twin gestations

Abstract

A shortened mid-trimester transvaginal cervical length (TVCL) is the strongest predictor of premature birth in twin gestations. Our objective was to determine the relative frequencies of adverse neonatal outcomes associated with a range of mid-trimester TVCL measurements. Retrospective cohort study of 403 twin gestations (806 neonates) delivered between 2003 and 2010. TVCL measurements were routinely obtained between 18-24 weeks’ gestation and the shortest of 3 measurement acquired was used to categorize each woman into the following cohorts: 0-10mm (n=21), 11-20mm (n=32), 21-30mm (n=61), 31-40mm (n=126), and > 40mm (n=163; referent group). Rates of individual and composite adverse neonatal outcomes were compared between the TVCL categories. Poisson regression with robust error variance was used to calculate the adjusted relative risk (aRR) and 95% confidence interval (CI) for composite adverse neonatal outcomes controlling for confounders. Shortened mid-trimester TVCL was strongly associated (p<.001) with composite neonatal morbidity/mortality with 89.5% of women with a TVCL 0-10mm experiencing a serious adverse outcome in at least one twin or 77.8% in both twins (Table 1). Compared to women with a TVCL >40 mm, those with a TVCL 0-10 mm had a significantly greater risk of experiencing composite neonatal morbidity/mortality (aRR: 1.6, CI: 1.2-2.2). A shortened mid-trimester TVCL was also significantly associated (p<.001) with each individual primary neonatal morbidity except Grade III/IV IVH and every secondary neonatal outcome except hypoglycemia (Table 2). Every woman with a TVCL 0-10mm had at least one baby admitted to the NICU with a median LOS of 33 days. Shortening of the TVCL in twin pregnancies is significantly associated with both individual and composite neonatal morbidity/mortality, NICU admission, and neonatal LOS. These data should be useful in more precisely counseling women carrying twins regarding neonatal implications of a shortened TVCL in mid pregnancy.View Large Image Figure ViewerDownload Hi-res image Download (PPT)