Due to fluctuating hormone levels a pregnant client may find their tolerance for everyday products diminishes and they are much more likely to experience irritation. If they do react to the procedure they will be unable to take antihistamines to calm it. Laying on their back for prolonged periods of time is also not recommended for pregnant women and they would probably find the treatment uncomfortable. Reassure your client that they can continue with lash extension after they have had their little one and explain that it's purely because their changing body may react to the chemical composition of the adhesive and you have their best interests at heart.

This is my personal opinion, if you feel your client will be fine then require a doctor’s note.