The role of folic acid in prevention of neural tube defects caused by high dose progesterone.

AIM To describe the effect of high dose progesterone (HDP) alone, or in combination with folic acid (FA), on occurrence of neural tube defects (NTDs) in chick embryo. MATERIAL AND METHODS 60 Fertile, specific eggs of Fyoumi species of chick were selected at zero hr of incubation. They were incubated at 37.5 °C and 75% relative humidity until the embryos reached stage eight of development. At this stage the eggs were divided into four groups consisting of 15 eggs/group. The 1st group was incubated without any operation. The 2nd group was injected with physiological saline. The 3rd and 4th groups were injected with HDP (20x physiologic dose of progesterone) and HDP with supplement of 5 micrograms/embryo of FA, respectively. After 48 hrs of incubation, all embryos were reviewed for the presence of NTDs under light microscopy. RESULTS None of the eggs in the control, and saline injection groups showed NTDs, whereas 75 % (9/12) of the embryos in the 3rd group, and 58.3 % (7/12) of the chick embryos in 4th group showed NTDs. CONCLUSION Exogenous progesterone at levels twenty times above its physiologic range in chick embryos causes NTDs. FA supplementation decreases the frequency of NTDs but does not abolish them.