Headache during pregnancy is very common it can be due to various reasons.most common one is not eating on time,acidity is the most common cause.if you give very big gap between meals you can start experiencing headaches.generally after lunch there will be big gap between lunch and dinner.this can cause headache.please take something in between.second reason can be hormones .most people experience headaches in first trimester.first thing is to try eating something .you can also use balms .if headache is still there you can take paracetamol which is considered safest medicine during pregnancy. towards 2nd and 3rd trimesters headaches start coming down.Sleeping helps in keeping your stress levels low.exercise and not putting too much weight all these things helps to prevent headaches.If headache still persists we can not always think this due to pregnancy only.This can be neurological cause also.in that case you mus see a physician.Sinus also another cause in Bangalore because of changing weather people have this allergic cold or allergic rhinitis which can lead to headaches.