I know when I was pregnant there was this constant annoying thump that I dealt with throughout my pregnancy. I always thought it was the baby tapping her foot or something lol. Drove me nuts. Anyway, after she was born I was holding her one day, and she got the hiccups. Her body reacted with the same rhythm as when she was in my tummy. I had an aha moment and realized my little muchkin had the hiccups while I was pregnant. Made perfect sense after the fact. She'll be 1 next month and she still gets the hiccups and has that same movement. It's kind of comforting when I hold her and she gets the hiccups for some reason : ) Reminds me of when she was completely all mine before she was born.
So I'm not sure if 7 weeks is too early to get hiccups. Just wanted to throw that out there as a possibility.