What specifically causes distinct texture changes at the root during pregnancy? & tips for managing

Any insights or papers on causation and management of this hormone-driven texture change at the root would be appreciated.

I am a biochemist and hairstylist. I have a client is due in May and has high density, thick, straight hair. We texturize the layers to lighten it for her, but it is very prone to buildup and feeling heavy.

She saw me November 17th and we did a charcoal detox because she complained of it being oily but still feeling dry, and tangles. The oily but dry nature told me the excess sebum is probably caused by (various compounding factors hut mostly) her sebum trying to rid buildup but hydrate the ends. I also educated her on oiling the ends, scalp oiling before shampoos, and deep moisturizing treatments. Sent her with a quality sebum balancing shampoo, a good conditioner, and an oil. This is typically my first line for girls like her.

She comes in today with her roots looking lighter in color (pregnancy band. seen it). She complained that it is unmanageable again (but she only tried scalp oiling and deep conditioning once. classic lol but love her).

What was interesting was that to the naked eye I couldn't see much texture difference, but when I ran my hands through I could definitely feel her roots were rougher, drier, almost curly feeling and made the mids extremely tangly. Her ends feel silky and straight (but a lil dry).

I pulled out my 200x microscope and her roots showed clear roughness with the cuticle when compared to even a few inches down where the cuticle was clean and sealed.

When I washed it, the water almost beaded up. Fascinating.

She isn't sleeping on it wet. isn't experiencing any dandruff. Isn't using excess heat that would affect the structure.

An interesting aside: She did mention she started taking collagen again, which I am sure has benefits but my instinct tells me the more protein in the hair=the more textured the structure tends to be.

Can taking collagen orally worsen the problem? (my instinct says the impact would be negligible)