**8. Conclusion**

The brain has a limited capacity to excrete NPs [111]. Therefore, NPs that bypass the blood brain barrier and reach the fetal brain during embryonic development result in neurodevelopmental toxicity in growing fetus and psychiatric disorders in offspring. Compelling evidence from animal studies on nanotoxicity during pregnancy shows that cautions must be taken by pregnant women when using NP-based products or medicine. Deeper understanding of interaction of NPS with the biological system and the underlying mechanism on neurotoxicity will help in the development of safety guidelines on the use of engineered NPs in medicine and commercial products without health hazard. However, there is a need to study the effects of long-term exposure to NP with realistic routes and levels of exposure to identify the chronic effects of NP to fetal nervous system.
