I had the opposite problem to you, OP, in that my extended family just didn't bother visiting after I had dd2 in 2012. Dd2 was born by ELCS and as I hadn't previously had one, I asked to be left alone for the first few days as I didn't know how I'd feel. They said okay, but we didn't have any cards, flowers, the usual stuff.
I actually felt fine after the birth and about one week later, invited them all over to our house (an aunt, four cousins and their children). No-one came: one cousin who I had been closest to promised to visit but let me down at the last minute 3 times over the subsequent weeks. She didn't meet dd2 until she was 12wo; it had to be at a cafe because I was so pissed off at her letting us down. My DM demanded that another cousin visit. She did, made lots of empty promises, then left.
We had been close before - my extended family are very arrogant, boastful, entitled people but they were my family. But this treatment sparked a lot of changes for me. I would have been assassinated if I'd treated any of them like this after the birth of a child of theirs. Then I came to realise that, actually, they are toxic people. As long as our relationships were on their terms, it would work. The minute I or another member of my immediate family shouts back, it's game over.
Everything came to an ugly head at the start of 2014 and I've been NC with them every since. I feel that the birth of dd2 and my showing hurt and disappointment was the spark that started the beginning of the end. Although I miss the feeling of a large family group, I don't miss them.
I hope it all works out for you 