(reference) and trace, with and without cervico-isthmic complex (CIC). We evaluated the predictive value of the different measure- ments for spontaneous delivery before 37 weeks using ROC curves. RESULTS: Our final study population comprised 508 women. The overall spontaneous preterm birth rate was 7.3%. The mean gesta- tional age at measurement was 19+5 weeks. Median cervical length ranged from 40.0 mm to 49.0 mm for the different techniques (p¼<0.001; Table 1). The area under the curve was 0.66 (95% CI 0.56-0.75) in the two-line without CIC, 0.63 (95% CI 0.52-0.73) in one-line without CIC and 0.65 (95% CI 0.56-0.75) in trace without CIC respectively. Using the measurement with CIC, the area under the curve was 0.66 (95% CI 0.54-0.78), 0.64 (95% CI 0.52-0.76) and 0.67 (95% CI 0.56-0.78) in two-line, one-line and trace respectively. CONCLUSION: While different measurement methods resulted in statistically significant differences in measured cervical length, this did not translate into clinically relevant better prediction of spon- taneous preterm birth. 435 Characteristics of cervical loop electrosurgical excision procedure (LEEP) and association with cervical length and subsequent pregnancy outcome Rachel L. Wood 1 , Danielle Panelli 1 , Whitfield Growdon 2 , Kevin Elias 2 , Anjuli Kaimal 2 , Sarah Feldman 1 , Thomas McElrath 1 1 Brigham and Women’ s Hospital, Boston, MA, 2 Massachusetts General Hospital, Boston, MA OBJECTIVE: To establish median cervical length in the pregnancy after LEEP and to identify any characteristics of LEEP or resultant pa- thology associated with adverse pregnancy outcome. STUDY DESIGN: This is a retrospective analysis of a cohort of women who underwent one cervical LEEP and had subsequent prenatal care and delivery at the same institution between July 1, 1994 and July 1, 2015. Women with multiple gestations, multiple LEEPs, or incom- plete records were excluded. The size of the specimen excised and pathology were abstracted from pathology reports. Cervical lengths were taken from the radiologic record. Obstetric outcomes were abstracted from the delivery record. RESULTS: A total of 92 women met inclusion criteria. The median gestational age at delivery was 39.0 weeks (interquartile range (IQR) 37.9-39.9) and 11 (12%) women had a preterm delivery (<37 weeks gestation). The median depth of LEEP specimen was 0.70cm (IQR 0.5-1.0). The median cervical length on first measurement was 3.6cm (IQR 3.3-4.0cm). Depth of excision of LEEP or calculated volume of tissue removed did not affect the risk for preterm delivery (p¼0.16 and p¼0.28, respectively). The most common pathological diagnosis was CINII/III (67.4%). When stratified by low grade (benign or CIN I) pathology versus high grade dysplasia (CIN II/III or ACIS), there was no difference in cervical length at 16-20 week survey (3.6cm vs 3.6cm respectively, p¼0.8), preterm delivery (13.8% vs 11.1%, p¼0.70), spontaneous labor (55% vs 57%, p¼0.77) or spontaneous rupture of membranes (43.8% vs 50.0%, p¼ 0.68, Table 1). CONCLUSION: In this cohort of 92 women who underwent one LEEP prior to pregnancy, the median second trimester cervical length was normal and the preterm birth rate was within the expected range among the general population. Midtrimester cervical length, LEEP characteristics, and pathologic diagnosis were not associated with increased risk of preterm birth. This adds to the body of literature questioning the association of LEEP with preterm birth. 436 Teleultrasound: A validation study Nader Rabie 1 , Adam Sandlin 2 , Song Ounpraseuth 2 , Wendy Nembhard 3 , Curtis Lowery 2 , Kelly San Miguel 2 , Everett Magann 2 1 Tripler Army Medical Center, Tripler, HI, 2 University of Arkansas for Medical Sciences, Little Rock, AR, 3 Arkansas Children’ s Hospital, Little Rock, AR OBJECTIVE: Ultrasound is a significant part of prenatal care, and teleultrasound is gaining popularity. It is associated with increased patient satisfaction and cost savings. However, there are no large studies validating teleultrasound. We hypothesize that the sensitivity and accuracy of teleultrasound are not inferior to on-site ultrasound. STUDY DESIGN: This is an IRB approved retrospective case control study conducted at a tertiary level care center. All targeted ultra- sounds performed within the study period were considered. Studies were excluded if performed less than 16 weeks’ gestation, multiple gestations and for reasons other than anatomy. Postnatal diagnoses were obtained from a mandatory birth defects surveillance program that records all birth defects in the entire state, from deliveries > 20 weeks’ gestation through infants up to 2 years of age. RESULTS: The teleultrasound and on-site ultrasound groups con- sisted of 2,368 and 3,145 studies respectively. The sensitivity of tel- eultrasound and on-site ultrasound were 57.46% and 76.57%, and the accuracy was 95.9% and 90.97% respectively. The observed sensitivity difference was -0.1911, therefore the sensitivity of tele- ultrasound is inferior to on-site ultrasound. The accuracy, positive and negative predictive values of teleultrasound are greater than on- site ultrasound. Poster Session II ajog.org S264 American Journal of Obstetrics & Gynecology Supplement to JANUARY 2018