It would have been interesting to also compare women pregnant with their second child. Is this phenomenon only seen in first time mothers?

I think kegamine is pointing to the grammatical oddity of using the singular "woman" in the title, rather than the plural "women":

  Pregnancy alters woman's brain

The article introduction phrases this in a little more concise a way:

  Pregnancy reduces grey matter in specific parts of a woman's brain

I can see how the introduction probably became contracted to form the title, but in the contracted version, the plural "Pregnancy alters women's brain" would seem a little more grammatically precise than "Pregnancy alters woman's brain".

> Stop trolling

Whoa. That's uncivil and a borderline personal attack, which isn't allowed on HN. Please assume good faith when commenting here.

On HN we frequently ask for titles to be altered for accuracy. I would expect a BBC journalist to understand the difference between singular and plural. "Woman's brain" and Women's brains" have different meanings, at least for this speaker of English.