first follow-up 75-g oral glucose tolerance test (OGTT) at 6-9 weeks postpartum, repeating the test every 6-12 months. We defined the condition in which infants were fed by breastfeeding greater than 80% of the volume at 6 months postpartum as high-intensity breastfeeding (HIB), while other statuses, including partial and non- breastfeeding, were non-HIB. We investigated the effect of HIB on the prevalence of postpartum diabetes in prepregnancy obese (body mass index [BMI]25) and non-obese (BMI< 25) women sepa- rately via univariate and multivariate analyses to control for con- founding variables, including age, family history of diabetes, glucose values on OGTT and insulin therapy. RESULTS: We included 518 women with GDM (363 non-obese and 155 obese). During the mean follow-up of 76.6 (median 59.6; range 7.1-218) weeks, 39 women (7.6%) were diagnosed with diabetes. The prevalence of postpartum diabetes was significantly lower in the HIB women than in the non-HIB women (5.7% vs. 10.7%, p< 0.05). However, while the effect was significant in the obese group (odds ratio [OR] 0.26 [95% confidence interval {CI} 0.07-0.81], p< 0.05), it was not in the non-obese group (0.74 [95% CI 0.33-1.76]). After controlling for confounders, the association between HIB and a reduced incidence of diabetes remained significant in the obese group (adjusted OR 0.25 [95% CI 0.06-0.83], p< 0.05). CONCLUSION: The protective effect of breastfeeding against the postpartum development of diabetes in Japanese women with cur- rent GDM was evident only in obese women. 743 Maternal serum alpha-fetoprotein(MSAFP) levels & relationship to ventriculomegaly with cases of fetal neural tube defects Romain Corroenne 1 , Katherine Zhu 1 , Emily Johnson 1 , Aline Bitarelli 1 , Jimmy Espinoza 1 , Ahmed A. Nassr 1 , Michael A. Belfort 1 , Roopali Donepudi 2 , Alireza A. Shamshirsaz 1 , Kjersti M. Aagaard 3 , William Whitehead 4 , Magdalena Sanz Cortes 3 1 Department of Obstetrics and Gynecology, Baylor College of Medicine/Texas Children’ s Hospital, Houston, TX, 2 Texas Children’ s Pavilion for Women, Baylor College of Medicine, Houston, TX, 3 Baylor College of Medicine, Houston, TX, 4 Texas Children’ s Hospital/Baylor College of Medicine, Houston, TX OBJECTIVE: To estimate the significance of association of mid- trimester MSAFP levels with neuroanatomic findings in cases of fetal open neural tube defect (ONTD). STUDY DESIGN: Retrospective study of patients with MSAFP quanti- fication referred to a single institution for prenatal NTD repair be- tween 2012 and 2018. MSAFP levels expressed as Multiple of the Median (MoM), were obtained from each patient at 15-22 weeks. For the purposes of this study, cases were classified into two groups based on calculated upper quartile of the mean: 1) Higher MSAFP levels (>4.5MoM) and group 2) lower MSAFP (4.5MoM). MRI scans performed at the time of referral (< 26 weeks of GA) were used to assess the relationship between MSAFP and: A)Ven- triculomegaly (mean lateral ventricular width 10mm); B)Level of hind brain herniation ( or < C2 most caudal cerebellum mea- surement); C)Size of the ONTD lesion [(length/2)x(width/2)xp for ellipse’ s surface); D)Anatomical level of lesion (LOL) ( or < L2 based on the location of the NTD upper vertebral body). Compar- isons between cases from Groups 1) and 2) were performed. RESULTS: 68 patients were included [54 prenatal (42 fetoscopic, 12 open), 14 postnatal repair]. No differences were detected regarding the type of lesion between Groups 1 and 2 (59% vs 65% of cystic NTD, p¼0.66). Ventriculomegaly was more common in cases from Group 1 compared to Group 2 (100% vs 72%, p¼0.01). There was a non-significant trend for a higher proportion of cases with severe ventriculomegaly (15mm) in Group 1 compared to Group 2 (29% vs 12%, p¼0.08). There were no differences regarding the size of the lesion [Group 1: 125(44-1036) vs Group 2: 141(38-632) mm 2 , p¼0.52], the anatomical LOL (L2: 23% vs 31%; p¼0.54) and more severe hind brain herniation (33% vs 40% < C2, p¼0.66). CONCLUSION: We have demonstrated that an MSAFP > 4.5MoM, measured in the 2nd trimester in a baby with ONTD, is associated with ventriculomegaly at midgestation. This is the first report of such an association, and may serve as a ready screening tool to facilitate efficient and timely transfer to a fetal center for indicated fetal repair. 744 Dietary intervention program for women at risk for preeclampsia Moria Klar 1 , Carmit Shani Levi 2 , Geila S. Rozen 2 , Ido Solt 3 1 Faculty of Nutritional Sciences, Tel-Hai College, Jerusalem, Israel, 2 Department of Clinical Nutrition, Rambam Health Care Campus, Haifa, Israel, 3 Rambam Health Care Campus, Haifa, Israel OBJECTIVE: Preeclampsia (PE) is a multi-system placental vascular disorder that adversely affects the mother and fetus. In developing countries, 10-20% of maternal mortality is directly related to PE. Low dose aspirin is recommended for PE prevention in high risk women. Calcium supplementation is recommended by the WHO in low intake areas. We conducted an intervention study to evaluate the preventive potential of a complete nutritional program (CNP) for pregnancies with risk factors for PE. STUDY DESIGN: A RCT multicenter trial that examined the influence of CNP on women with risk factors for PE, implemented from the 8th gestational week to delivery was conducted during April 2015 - October 2017. Forty-six pregnant women with risk factors for PE were divided to two groups; the intervention group (N¼26) received 8 CNP sessions, nutritional supplementation of calcium and vitamin D, and dietary weight control counseling. The control group (N¼20) received 5 follow up sessions with no nutritional counseling. The collected data included anthropometric measurements, blood pres- sure, 24h dietary recall, and neonatal outcomes RESULTS: There was no significant differenced in demographic data between groups at inclusion. For the intervention group calcium, vitamin D and iron consumption were significantly higher during pregnancy (P< 0.05) (Figure 1). Satisfaction from followup was significantly higher in the intervention group. No significant dif- ferences between the study groups were observed regarding blood pressure, newborn weight or delivery mode. Two cases of hyper- tension and one of PE were observed in the control group, compared to none in the intervention group, with no statistical significance due to small group size. CONCLUSION: Our intervention program showed feasibility, motiva- tion and compliance of pregnant women with risk factors for PE to participate in a nutritional counseling intervention program aimed to improve nutritional status during pregnancy. Further research is needed to investigate the possible clinical influence of targeted nutritional counseling intervention programs on PE incidence and severity. Poster Session III ajog.org S470 American Journal of Obstetrics & Gynecology Supplement to JANUARY 2020