There are two different consequences spoken to the woman in Genesis 3:16:
And to the woman He said, "I will make most severe your pangs in childbearing; in pain shall yo bear children... (JPS)
אל-האשה אמר הרבה ארבה עצבונך והרנך בעצב תלדי בנים
The first is the obvious עצבונך והרנך, which is the physical pain of childbirth.
The second is בעצב תלדי בנים, which speaks more to the issues of raising a child. For example, after childbirth there will be the "terrible twos." Both are painful and yet the second type is different from the first.
בעצב is the less common word. A good example of the context in Genesis is found in Psalm 127:
1 Except the LORD build the house, they labour in vain that build it: except the LORD keep the city, the watchman waketh but in vain.
2 It is vain for you to rise up early, to sit up late, to eat the bread of sorrows: for so he giveth his beloved sleep.
3 Lo, children are an heritage of the LORD: and the fruit of the womb is his reward. (BRG)
Rising up early or staying up late to eat the bread of "sorrows" describes a condition a parent will experience while a child grows. This is intermittent and reoccurring pain and different from the pain of childbirth; it can be physical and/or mental. It could be considered "mental anguish."
For the first woman and man, their rebellion led to their expulsion from the garden. In essence HaShem gave them what they wanted, mastery over their life. Instead of eating fruit HaShem provided, the man now had to provide his own food; instead of bringing forth children in the Garden, the woman brought forth children outside. There she would experience both types of pain: the pain of childbirth and the pain of child rearing.
There is also a prophetic element to HaShem's words. When Cain killed Abel, the woman was not physically hurt by Cain's blow(s) on Abel. She experienced none of the physical pain as she did during childbirth. Yet we know she experienced an even greater pain as on one day she lost both of her sons, one to physical death, the other to banishment. Undoubtedly, this pain did not subside or ever become a "thing of the past" as the pains from childbirth had.