1. Cuningham FG, Leveno KJ, Bloom SI, Hauth JC, Gilstrap III L, Weastrom KD. Williams obstetrics. 22nd ed.
                                                                                                                New York:McGraw-Hill;2005.
                                                                                                                2. Khosrowbeygi A, Lorzadeh N, Ahmadvand H, Shiravand Y. Homocysteine and its association with lipid
                                                                                                                peroxidation and leptin in preeclampsia. Int J Biol Chem 2011;5(3):184-92..
                                                                                                                3. Guven MA, Coskun A, Ertas IE, Aral M, Zencirci B, Oksuz H. Association of maternal serum CRP, IL-6, TNFalpha,
                                                                                                                homocysteine, folic acid and vitamin B12 levels with the severity of preeclampsia and fetal birth weight.
                                                                                                                Hypertens Pregnancy 2009 May;28(2):190-200.
                                                                                                                4. Nadafi M, Mohammad Hosseini S, Afrasiabyfar A, Momeni E, Malekzadeh GM. [Association of homocysteine,
                                                                                                                vitamin and blood factors with preeclampsia in pregnant women] [Article in Persian]. J Armaghane Danesh
                                                                                                                2010 Summer;15(2):171-80.
                                                                                                                5. Makedos G, Papanicolaou A, Hitoglou A, Kalogiannidis I, Makedos A, Vrazioti V, et al. Homocysteine, folic
                                                                                                                acid and B12 serum levels in pregnancy complicated with preeclampsia. Arch Gynecol Obstet 2007
                                                                                                                Feb;275(2):121-4.
                                                                                                                6. Wen SW, Chen XK, Rodger M, White RR, Yang Q, Smith GN, et al. Folic acid supplementation in early second
                                                                                                                trimester and the risk of preeclampsia. Am J Obstet Gynecol 2008 Jan;198(1):45.e1-7.
                                                                                                                7. Manizheh SM, Mandana S, Hassan A, Amir GH, Mahlisha KS, Morteza G. Comparison study on the effect of
                                                                                                                prenatal administration of high dose and low dose folic acid. Saudi Med J 2009 Jan;30(1):88-97.
                                                                                                                 
                                                                                                                8. Rahimi G, Tazakori Z, Shateri N. [Relation between homocysteine serum levels and pregnancy complicated
                                                                                                                with preeclampsia occurrence] [Article in Persian]. J Ardebil Med Univ Sci 2010 Summer;10(2):121-7.
                                                                                                                9. Braekke K, Ueland PM, Harsem NK, Karlsen A, Blomhoff R, Staff AC. Homocysteine, cysteine, and related
                                                                                                                metabolites in maternal and fetal plasma in preeclampsia. Pediatr Res 2007 Sep; 62(3):319-24.
                                                                                                                10. Vollset SE, Refsum H, Irgens LM, Emblem BM, Tverdal A, Gjessing HK, Monsen AL, et al. Plasma total
                                                                                                                homocysteine, pregnancy complications, and adverse pregnancy outcomes: the Hordaland Homocysteine study.
                                                                                                                Am J Clin Nutr 2000 Apr;71(4):962-8.
                                                                                                                11. Mislanova C, Martsenyuk O, Huppertz B, Obolenskaya MY. Placental markers of folate-related metabolism in
                                                                                                                preeclampsia. Reproduction 2011 Sep;142(3);467-76.
                                                                                                                12. Katre P, Bhat D, Lubree H, Otiv S, Joshi S, Joglekar C, et al. Vitamin B12 and folic acid supplementation and
                                                                                                                plasma total homocysteine concentrations in pregnant Indian women with low B12 and high folate status. Asia
                                                                                                                Pac J Clin Nutr 2010;19(3):335-43.
                                                                                                                13. Acilmis YG, Dikensoy E, Kutlar AI, Balat O, Cebesoy FB, Ozturk E, et al. Homocysteine, folic acid and
                                                                                                                vitamin B12 levels in maternal and umbilical cord plasma and homocysteine levels in placenta in pregnant
                                                                                                                women with pre-eclampsia. J Obstet Gynaecol Res 2011 Jan;37(1):45-50.
                                                                                                                14. Bibi S, Qureshi M, Ahmad M, Qureshi PM, Memon A, Qazi RA. Hyperhomocysteinaemia, vascular related
                                                                                                                pregnancy complications and the response to vitamin supplementation in pregnant women of Pakistan. J Pak
                                                                                                                Med Assoc 2010 Sep;60(9):741-5.
                                                                                                                15. Wen SW, Chen XK, Rodger M, White RR, Yang Q, Smith GN, et al. Folic acid supplementation in early
                                                                                                                second trimester and the risk of preeclampsia. Am J Obstet Gynecol 2008 Jan;198(1):45.e1-7.
                                                                                                                16. Acilmis YG, Dikensoy E, Kutlar AI, Balat O, Cebesoy FB, Ozturk E, et al. Homocysteine, folic acid and
                                                                                                                vitamin B12 levels in maternal and umbilical cord plasma and homocysteine levels in placenta in pregnant
                                                                                                                women with pre-eclampsia 2011 Jan;37(1):45-50.
                                                                                                                17. Bánhidy F, Dakhlaoui A, Dudás I, and Czeizel AE. Birth outcomes of newborns after folic acid
                                                                                                                supplementation in pregnant women with early and late pre-eclampsia: a population-based study. Adv Prev Med
                                                                                                                2011;2011:127369.
                                                                                                                18. Ueland PM, Vollset SE. Homocysteine and folate in pregnancy. Clin Chem 2004;Aug;50(8):1293-5.
                                                                                                                19. Murphy MM, Fernandez-Ballart JD. Homocysteine in pregnancy. Adv Clin Chem 2011;53:105-37. Review.
                                                                                                                20. Viskova H, Vesela K, Janosikova B, Krijtj J, Visek JA, Calda P. Plasma cysteine concentrations in
                                                                                                                uncomplicated pregnancies. Fetal Dragn Ther 2007;22(4):254-8,
                                                                                                                21. Onalan R, Onalan G, Gunenc Z, Karabulut E. Combining 2nd-trimester maternal serum homocystein levels and
                                                                                                                uterine artery Doppler for prediction of preeclampsia and isolated intrauterine growth restriction. Gynecol
                                                                                                                Obstet Invet 2006;61(3):142-8.
                                                                                                                22. Begum JA, Chowdhury TA, Biswas KB, Ali L. Vitamin B12 and folate status in preeclamptic women in
                                                                                                                Bangladesh. BJMS 2009; 15(2):83-86.
                                                                                                                23. Kawai K, Spiegelman D, Shankar AH, Fawzi WW. Maternal multiple micronutrient supplementation and
                                                                                                                pregnancy outcomes in developing countries: meta-analysis and meta-regression. Bull World Health Organ 2011
                                                                                                                Jun 1;89(6):402-411B.
                                                                                                                24. Mignini LE, Latthe PM, Villar J, Kilby MD, Carrolin G, Khan KS. Mapping the theories of preeclampsia: the
                                                                                                                role of homocysteine. Obstet Gynecol 2005 Feb;105(2):411-25.
                                                                                                                25. Fernández M, Fernández G, Diez-Ewald M, Torres E, Vizcaíno G, Fernández N, et al. [Plasma homocysteine
                                                                                                                concentration and its relationship with the development of preeclampsia. Effect of prenatal administration of
                                                                                                                folic acid] [Article in Spanish]. Invest Clin 2005 Jun;46(2):187-95.
                                                                                                                26. Karpit P, Balla J, Szoke G, Bereczky Z, Pall D, Ben T, et al. [Frequency of hyperhomocysteinemia in
                                                                                                                hemodialysis patients with folic acid supplementation] [Article in Hungarian]. Orv Hetil 2002 Jul
                                                                                                                7;143(27):1635-40.
                                                                                                                27. Powers RW, Dunbar MS, Laivuori HM, Harger GF, Lykins dl, Roberts JM. Maternal plasma homocysteine
                                                                                                                concentrations are not increased in twin pregnancies. Hypertens Pregnancy 2005;24(1):49-58.
                                                                                                                28. Acılmıs YG1, Dikensoy E, Kutlar AI, Balat O, Cebesoy FB, Ozturk E, et al. Homocysteine, folic acid and
                                                                                                                vitamin B12 levels in maternal and umbilical cord plasma and homocysteine levels in placenta in pregnant
                                                                                                                women with pre-eclampsia. J Obstet Gynaecol Res 2011 Jan;37 (1):45–50..