Last month, the "How I Met Your Mother" actress, 38, was among the many Hollywood moms congratulating (via Twitter) Jessica Simpson on the birth of her daughter, Maxwell Drew. Joked Hannigan, "Does this mean I now have the biggest bump?" (The star also cracked that people assumed she was "ready to pop" as early as April.)
The "Buffy the Vampire Slayer" alumna wed Denisof, 46 (who starred on "Buffy" spin-off "Angel"), in October 2003.
"[Being a mother] has changed me in every way because my life is so much greater," Hannigan told Us in May 2010. "It filled a void I never knew was there -- it's the most amazing experience of my life. I just feel so blessed to get to be on this journey, to be a mommy. [Satyana] is just the greatest baby.
Keep clicking to see photos of Alyson and her family ...