Aim:
Background: This study focusing on report the LD50 for all compound and effect of different types of normal saline on development stage in chick embryo cardiovascular system, specially this model similar to human protein coding gene as well as more ethics and can be determined the suitable dose for injection. Aim is to estimate the effect of normal saline on early development stage of embryo during pregnancy after LD50 dose determination and to record of heart Electrocardiogram ECG for chick embryo and make histopathological sections for the heart to find if it suitable for pregnant women.

Material and methods:
Materials and methods: Novel data- acquisition record for embryo ECG, vision findings as well as histopathological study for 42h of development can support the exact harm and sudden death causes for embryo during first months of pregnancy.

Results:
Results: LD50 results show significant variation (p<0.05) between dose 2µl and other lethal doses and ECG show same variation according to recording in amplitude, QRS, and heart rate on the other hand the histopathological slides show clear teratology signs of veins malformation specially in dose 6, 8, and 10 µl and heart muscle rupture with sign of edema and pathological apoptosis.

Conclusions:
Conclusions: Due to harmful effect of normal saline on chick embryo development especially heart and veins which lead to sudden death, they must not use for pregnant women during first 4 months or before pregnancy.