Ok... Just sharing my knowledge on food supplement. My background? I used to work in a pharmaceutical company dealing with food supplement. Try to consider the points and try discussing with a Qualified Healhcare Professionals ya?

DHA = highly recommended for child's brain developement especially from baby till 5 years old. After that, not much use as the brains is well developed.

For pregnant mothers, depending on the source of the dha, if from milk formula, it should be safe if u follow the drinking dosage. But if from food supplement such as fish oil, then u might wanna consult your doctor as in fish oil, apart from having dha, it also consists EPA that might cause thinning of the blood which are very dangerous during labour as it might cause lose of blood.