well you should i mean like common courtesy but your not obligated to DO anything
usually yes
When someone gives you a baby shower a nice Thank You card is sufficient and you do not have to give them a gift.
TOTALLY
If you gave a baby shower gift earlier than the due date of the baby shower then you do not need to give a gift, but if you just gave the gift not knowing about the baby shower you could give the mother to be a small gift for the baby.
Baby jewelry is a great gift for a baby shower! Go to http://www.cornerstorkbabygifts.com/baby-jewelry.aspx to find a great gift for any baby shower.
When you go to a Wedding or Baby Shower and have no gift wrap you can buy decorative bags to put the give in and then cover it in tissue paper.
A baby shower gift that will stand out from the rest is books. Most people don't give books as baby shower gifts, and many new moms love books on parenting, teaching baby to read, and infant development the first year.
You are never required to give a gift. If you don't go, you MAY send something, but you don't have to. Many people wait and give a gift when the baby is born.
There are never enough diapers for a new baby, there are even cute diaper cakes that make good shower gifts. A personalized gift is always nice, something with the baby's name on it. Gift card for a restaurant is always nice because they may not have time to cook with a new baby.
A gift certificate to a popular shop where they sell baby clothes, etc., would be a better gift than giving money.
* If you are not invited to the shower then it is up to you whether you would like to give a gift or not, but you don't have to. If you were invited, but can't make the shower then yes, you should send the gift with someone else you know that is attending or stop by and give the gift AFTER the shower to the person the shower is for.
A unique gift for a baby shower is something personalized for the new baby. A monogram of the baby's initials or a wall hanging with the letters of their name is a fun, different choice.