Hair care during pregnancy
Hair care products such as shampoo, conditioner, or hairdye don't appear to be harmful during pregnancy. This applies to the DIY packages as well as the hairdresser's professional products. There is also no evidence that cosmetics are harmful during pregnancy. Nevertheless specialists usually advise not to use hair dye or related products in the first trimester.
If you're going to color your hair, the hair tone may look different from the color you expected. This is because the proteins in your hair change during pregnancy. Do not try to use oil-based dye. Water-based products in a ventilated area will be okay.
What the hairdressers say
Most hairdressers say that pregnancy can hamper, or even change your hair's reaction to dye and other hair products. The hair can be straight rather than curly, curly instead of straight, orange instead of brown. It is best to choose a hair style that you can easily take care of without having to use chemicals.
Under the influence of hormones your hair may fall out after childbirth. That is perfectly normal and it will grow back.
From angelababy In Q&A