www.AJOG.org Prematurity, Physiology Poster Session V

first trimester miscarriage, and 1 who had an elective termination ofpregnancy. Of the remaining 443 patients, 8.8% (39) delivered priorto 37 weeks. Among the first trimester cohort, 48% (10/21) ofwomen who delivered prematurely had fetal adrenal gland mea-surements that were larger than the average. Among the secondtrimester cohort, 44% (8/18) of women who delivered prematurelyhad fetal adrenal gland measurements that were larger than theaverage (see graph).CONCLUSION: Fetal adrenal gland measurements in the first andsecond trimester do not appear to be predictive of future pretermbirth. Changes in fetal adrenal gland size associated with pretermdelivery in the third trimester are more likely an acute part of theprocess associated with preterm delivery.

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Development and validation of a prediction tool toidentify women with a multiple pregnancy who could benefitfrom cervical pessariesParvin Tajik1, Sophie Liem2, Ewoud Schuit2, Kitty Bloemenkamp3,Hans Duvekot4, Bas Nij Bijvank12, Maureen Franssen5,Martijn Oudijk6, Martina Porath7, Liesbeth Scheepers11,Marko Sikkema8, Mallory Woiski9, Ben Willem Mol2,Dick Bekedam10, Patrick Bossuyt1, Mohammad Hadi Zafarmand21Academic Medical Centre, Amsterdam, Epidemiology, Biostatistics &Bioinformatics - Obstetrics & Gynaecology, Amsterdam, Netherlands,2Academic Medical Centre, Amsterdam, Obstetrics and Gynecology,Amsterdam, Netherlands, 3Leiden University Medical Centre, Obstetrics &Gynaecology, Leiden, Netherlands, 4Erasmus Medical Centre, Obstetrics &Gynaecology, Rotterdam, Netherlands, 5University Medical CentreGroningen, Obstetrics & Gynaecology, Groningen, Netherlands, 6UniversityMedical Centre Utrecht, Obstetrics & Gynaecology, Utrecht, Netherlands,7Máxima Medical Centre, Obstetrics & Gynaecology, Veldhoven,Netherlands, 8ZGT, Almelo, Obstetrics & Gynaecology, Almelo, Netherlands,9Radboud University Nijmegen, Obstetrics & Gynaecology, Nijmegen,Netherlands, 10Onze Lieve Vrouwe Gasthuis, Obstetrics & Gynaecology,Amsterdam, Netherlands, 11Academic Hospital Maastricht, Obstetrics &Gynaecology, Maastricht, Netherlands, 12Isala Clinics, Zwolle, Obstetrics &Gynaecology, Zwolle, Netherlands

OBJECTIVE: The ProTWIN trial showed that in unselected womenwith a multiple pregnancy, prophylactic use of a cervical pessary didnot reduce poor perinatal outcome. The pre-specified subgroupanalysis identified women with short cervix as a subgroup whobenefits form the pessaries. We aim to develop and validate a multi-marker treatment selection model to help us with identifying thosewho could benefit from pessary.

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STUDY DESIGN: We used data of ProTWIN trial in which 808 womenwith a multiple pregnancy were randomly assigned to cervical pes-sary or control. We randomly selected 2/3 of participants (n¼525)for model development and1/3 for validation. We developed twomodels for predicting the outcome, one in pessary and one in no-pessary group. For each woman in the validation set (n¼266) theexpected benefit from pessary was calculated as the difference in therisk with and without pessary. We tested if the predicted benefit isassociated with the observed benefit.RESULTS: Factors predicting the risk of poor outcome without pes-sary were short cervix, monochorionicity, nulliparity and previouspreterm. Risk factors of poor outcome with pessary were tripletpregnancy, nulliparity and previous preterm. In the validation set,women with higher predicted benefit from pessary had betteroutcome on pessary while those with predicted benefit from no-pessary had better outcome on no-pessary (p for interaction ¼0.013). 43% of women were predicted to benefit from pessary. Theobserved average benefit from pessary in those predicted to benefitwas 9%(95%CI 2-24%) and the average benefit of no-pessary inwomen who predicted to no-benefit was 5%(95%CI 2-13%).CONCLUSION: We developed a tool for identifying women withmultiple pregnancy who could benefit from cervical pessary. Ourvalidation analysis showed that the use of the tool could potentiallyimprove selection of patients for pessary insertion and consequentlyreduce the poor neonatal outcomes in multiple pregnancy.

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Oxidative stress in pregnancies affected by IUGR andmacrosomiaMargarida Y. Y. Lei1, Suvajit Sen1, Gautam Chaudhuri1,Carla Janzen11David Geffen School of Medicine at UCLA, Department of Obstetrics andGynecology, Los Angeles, CA

OBJECTIVE: This research seeks to measure markers of oxidative stressin the placenta of pregnancies affected by IUGR and macrosomia.Free radicals such as superoxide and nitric oxide increase duringpregnancy and result in oxidative stress. The body compensates forthe free radicals by producing antioxidant enzymes. Previous studieshave shown a link between oxidative stress and low birth weight(IUGR). IUGR and excessive birth weight (macrosomia) each occurin up to 10% of all births. This study seeks to link the expression andactivity of specific antioxidants and antioxidant enzymes with IUGRand macrosomia. In this study, we looked at GPx1, SOD, Catalase,NADP/NADPH, concentration of Free Fatty Acid, and Acetyl-CoA.STUDY DESIGN: Placentas of volunteer subjects were separated intomaternal and fetal parts and analyzed via Western Blot, ELISA, RT-PCR, and immunohistochemistry for enzyme expression and ac-tivity. The results were correlated to macrosomia (n¼11), IUGR(n¼14) and normal (n¼12).RESULTS: The maternal aspects of the placenta from pregnancyaffected by macrosomia showed no change in Catalase activity,significantly higher GPx activity and GPx1 mRNA expression, andtrends in all other antioxidants and antioxidant enzymes. The fetalaspect of the placenta from macrosomia births showed no change inCatalase activity, significantly higher GPx activity, and trends in allother antioxidants and antioxidant enzymes. The maternal aspect ofthe placenta from IUGR births showed no difference in Catalaseactivity and trends in all other antioxidants and antioxidant en-zymes. The fetal aspect of the placenta from IUGR births showed nochange in Catalase activity or SOD activity and trends in all otherantioxidants and antioxidant enzymes.

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