505: Prediction of preterm birth in triplet pregnancy

Abstract

Lidewij van de Mheen, Anita Ravelli, Maria van Pampus, Christianne de Groot, Eva Pajkrt, Ben Willem Mol Onze Lieve Vrouwe Gasthuis Amsterdam, Obestetrics and Gynaecology, Amterdam, Netherlands, Academic Medical Center, Medical Informatics, Amsterdam, Netherlands, Onze Lieve Vrouwe Gasthuis, Obestetrics and Gynaecology, Amsterdam, Netherlands, VU Medical Centre, Obstetrics and Gynaecology, Amsterdam, Netherlands, Academic Medical Center, Department of Obstetrics and Gynaecology, Amsterdam, Netherlands, Dutch consortium AMPHIA trial, ., ., Netherlands OBJECTIVE: Some clinicians advise prophylactic administration of antenatal steroids for fetal lung ripening in women with a triplet pregnancy, irrespective of the development of signs and symptoms that announce preterm delivery. The aim of this study was to assess the natural course of triplet pregnancies by calculating the risk of delivery in a particular time frame during gestation. STUDY DESIGN: We collected data on all triplet pregnancies in the Netherlands from 1999-2007 from the Dutch Perinatal Registration (PRN). From these data, we constructed a Kaplan Meier curve for time to delivery, and calculated the risk of delivery within two weeks for different gestational ages. RESULTS: Between 1999 and 2007, there were 575 triplet pregnancies in the Netherlands, of which 367 after artificial reproductive techniques and 208 after spontaneous conception. The mean gestational age at delivery was 32.8 weeks (SD 3.8 weeks) (figure 1), Artificially conceived triplets were on average 0.4 weeks longer pregnant (data not shown). There were 22 pregnancies (4%) that ended before 24 weeks. At a gestational age of 24 weeks, the change to deliver within the next two weeks was 2%. For 26, 28, 30 and 32 weeks these risks were 5%, 6%,13% and 31%, respectively (table 1). The probability to continue the pregnancy until a gestational age of 37 weeks was approximately 7%. CONCLUSION: Mean gestational age for triplet pregnancies in The Netherlands was 32.8 weeks. Before 32 weeks of gestation, prophylactic administration of steroids is not indicated. At a gestational age of 32 weeks, prophylactic antenatal corticosteroids could be considered in a triplet pregnancy. 506 Midtrimester Vitamin D status is not associated with spontaneous preterm birth prior to 35 weeks Luisa Wetta, Joseph Biggio, Suzanne Cliver, Adi Abramovici, Stephen Barnes, Alan Tita University of Alabama at Birmingham, Obstetrics & Gynecology, Birmingham, AL, University of Alabama at Birmingham, Department of Pharmacology and Toxicology, Birmingham, AL OBJECTIVE: Preterm birth (PTB) has been associated with deficient maternal vitamin D status in some studies. Measurement methodologies, patient populations, and seasonal variation may all affect results. We evaluated whether midtrimester serum vitamin D levels are associated with spontaneous(S) PTB prior to 35 weeks gestation. STUDY DESIGN: We conducted a nested case-control study of 100 women with SPTB prior to 35 weeks gestation (cases) and 200 healthy women who delivered at 39-40 weeks (controls). Stored remnant serum specimens from a midtrimester sample drawn between 15-21 weeks gestation for multiple marker screening were tested for total 25-hydroxy vitamin D levels (25-OH D) using a validated liquid chromatography-tandem mass spectrometry method considered the gold standard for 25-OH D quantitation. We compared mean 25-OH D levels as well as prevalence of vitamin D insufficiency (25-OH D level 30 ng/mL) and vitamin D deficiency (25-OH D 15 ng/mL). Logistic regression was used for multivariable adjustments. RESULTS: A total of 90 SPTB cases and 177 controls had remnant specimens with valid measurements. Data are provided in the Table. African Americans were more likely to be vitamin D deficient than other races (24.5% versus 3.7%, p 0.0001) as were women with specimens drawn between Oct and Apr (20.9% versus 9.2%, p 0.011). Mean midtrimester 25-OH D levels were similar between cases and controls. After adjusting for age, race, parity, weight, and season of specimen collection, neither vitamin D insufficiency (Adjusted OR: 0.8; 0.4-1.4) www.AJOG.org Doppler Assessment, Fetus, Prematurity Poster Session III