News Donald Trump Jr. Expecting Baby # 4 By Krista Wick 6:21 PM PDT, May 2, 2012 Getty Images Just six months after giving birth to son Tristan Milos, Donald Trump Jr.'s wife Vanessa is pregnant again with the couple's fourth child.RELATED: 'Celebrity Apprentice' Goes Medieval "Well, Vanessa & I have some good news," Trump Jr. wrote to his Twitter account this afternoon. "We are expecting baby num 4 in the fall!!!"The new bundle of joy will make a little brother or sister to six-month-old Tristan Milos, Kai, 4, and Donald III, 3. Vanessa and Donald tied the knot in 2005 at Trump Sr.'s Mar-a-Lago estate in Palm Beach, Florida.