Table. Cerclage and Sonographic Cervical Characteristics Sludge Present (n66) No Sludge Present (n39) P Value Prophylactic Cerclage 43/66 (65%) 27/39 (69%) p=0.668 (NS) .......................................................................................................................................................................................... Emergent Cerclage* 23/66 (35%) 12/39 (31%) p=0.668 (NS) .......................................................................................................................................................................................... Gestational Age at Cerclage Placement (weeks) 16.9 +- 3.2 15.7 +-2.9 p=0.043 (S) .......................................................................................................................................................................................... Funnel Present 60 (90%) 4 (10%) p0.0001 (S) .......................................................................................................................................................................................... Mean Total Cervical Length(cm) 1 2.81+-1.01 3.94+-0.60 p0.0001 (S) .......................................................................................................................................................................................... Mean Proximal Cerclage Length 1 (cm) 1.22 +-0.88 2.01 +-0.61 p0.0001 (S) .......................................................................................................................................................................................... Proximal CL:Total CL Ratio 0.503+-0.123 0.377+-0.024 p=0.0006 (S) .......................................................................................................................................................................................... Mean Distal Cerclage Length 1 (cm) 1.6+-0.39 1.94 +-0.46 p=0.0001 (S) .......................................................................................................................................................................................... Distal CL:Total CL 1 Ratio 0.406 +-0.095 0.461+-0.12 p=0.0097 (S) .......................................................................................................................................................................................... McDonald Technique (%) 97 95 p=0.627(NS) .......................................................................................................................................................................................... Mean Sonographic Cervical Evaluation post cerclage (days) 19.6 18.6 P=0.766(NS) .......................................................................................................................................................................................... Shirodkar Technique (%) 3 5 p=0.627(NS) .......................................................................................................................................................................................... Suture used: Ethibond (%) 33 51 p=0.07 (NS) .......................................................................................................................................................................................... Suture used: Mersilene (%) 67 49 p=0.07 (NS) .......................................................................................................................................................................................... 1 All Cervical Length measurements taken after placement of Cervical Cerclage. * Defined as membranes visible at external cervical os. 178 Time from elective removal of ultrasound-indicated cerclage to birth Vincenzo Berghella 1 , Jeff Szychowski 2 , for the Vaginal Ultrasound Trial Consortium 3 1 Thomas Jefferson University, Philadelphia, PA, 2 University of Alabama at Birmingham, Birmingham, AL, 3 Multicenter OBJECTIVE: To estimate if degree of cervical shortening in second tri- mester, prior birth outcomes, and suture type affect the time from cerclage removal to birth. STUDY DESIGN: Time from elective removal of cerclage (at around 36- 37weeks) until birth was evaluated in a secondary analysis of the Vag- inal Ultrasound Cerclage Trial. Singleton gestations, with prior spon- taneous preterm birth (PTB) 16-33 6/7weeks, had ultrasound- indicated cerclage performed for short cervical length (CL) 25mm at 16-23 6/7weeks. Cases of non-elective cerclage removal (for labor, rupture of membranes, or other fetal or maternal indications) were excluded. Women with short CL 15.9mm were compared to those with CL 16-24.9mm. Earliest prior PTB gestational age (GA), most recent birth GA, CL at randomization, and type of suture were also analyzed as variables having possible effects on outcomes. Primary outcome was time between removal of cerclage and birth. Secondary outcomes were incidence of birth 48hours and 7days from cer- clage removal. RESULTS: 70 women were analyzed. The mean GA at cerclage removal was 36.7 0.8weeks. 10 (14%) women delivered within 48hours, and 16 (23%) delivered within 7days of cerclage removal (mean 13.8 8.7). No significant relationship was observed between randomiza- tion CL class and days until birth (Table). No significant relationship was observed in univariate linear regression analyses modeling days to delivery as a function of earliest prior PTB GA (p=0.79), most recent birth GA (p=0.83), or CL at randomization (p=0.14). Type of suture were mersilene tape (n=27), mersilene braided suture (n=25), and monofilament suture (e.g. Prolene; n=18). There was no significant difference in days between cerclage removal and birth (p=0.17), birth within 48hours (p=0.44), or birth within 7days (p=0.34) among su- ture types. CONCLUSIONS: CL at randomization, prior birth outcomes, and suture type do not affect time from elective removal of cerclage to birth. The mean time to birth after cerclage removal is about 14 days, and only 14% of these women deliver within 48 hours of cerclage removal. Total (n70) CL <15.9 mm (n17) CL 16-24.9 mm (n53) p value Time cerclage removal - birth (days) 13.8 8.7 15.9 7.1 13.2 9.1 0.27 .......................................................................................................................................................................................... Birth 48hrs after removal 10 (14%) 1 (6%) 9 (17%) 0.43 .......................................................................................................................................................................................... Birth 7days after removal 16 (23%) 2 (12%) 14 (26%) 0.32 .......................................................................................................................................................................................... 179 Maternal vitamin D status and twin pregnancy outcome William Goodnight 1 , Sina Haeri 1 , Arthur Baker 1 , Carlos Camargo 2 1 University of North Carolina at Chapel Hill, Chapel Hill, NC, 2 Massachusetts General Hospital, Boston, MA OBJECTIVE: Determine the incidence of vitamin D insufficiency, and determine the association of vitamin D status and length of gestation and birth weight (BW) in twin pregnancy. STUDY DESIGN: Retrospective analysis of all twin pregnancies delivered at UNCH between 2000-10 with midtrimester maternal serum aneu- ploidy screening was performed. Aneuploid/anomalous fetuses ex- cluded. Maternal vitamin D status was measured from maternal se- rum obtained at aneuploidy screening by LC-MS. Pregnancy outcome data (BW, z-score BW, gestational age at delivery, preeclampisa, dis- cordant BW  20%) were compared to maternal vitamin D status. Vitamin D sufficiency was defined as  75 nmol/L, deficiency  37.5 nmol/L. Deliveries less than 24 weeks EGA were excluded from BW analysis. Chisq/Fisher and Wilcoxon rank-sum analysis was per- Poster Session I Clinical Obstetrics, Neonatology, Physiology-Endocrinology www.AJOG.org S82 American Journal of Obstetrics & Gynecology Supplement to JANUARY 2011