My partner is European, and traditionally, in his culture, baby showers are held AFTER the baby is born as indicated in this article. This is great, as, when a baby is first born, sometimes you are not sure of the size (for clothing purchases), and for those who wish to wait to find out the sexe of their own baby, they won't have to concern themselves with the number of light greens, oranges and yellows they'd get for their bundle of joy, as most wish to buy clothes for baby but won't want to tempt fate by getting either blues or pinks. Not to mention that during the first few weeks of baby hood, your little ones needs are quite basic. As the time progresses, you'll be grateful for the much needed "stuff" party to help fill the gaps of things you haven't thought of just yet.
Always remember moms personality and wishes when hosting a shower...and always remember to get a little somthing-somthing for mom; luxry bath products, skin cream, sented candles a new night gown, just for her. She will appreciate it.