Maci was 5 months pregnant and didn't know?

I'm on my 1st first rewatch, Season 6. Production zoomed in on Maci's belly a lot during the period of time before she made the announcement. Maci asking her family and friends if she is getting fat (smh) was the real tip off for me- it was pretty obvious she was pregnant. At 5 months shouldn't you feel the baby kick?

She told the Xray doc there was no movement but apparently you can see the outline of the baby kicking during the CT scan (a reddit user said so, so it must be true lol).

Which leads me to question, why did she wait so long? I understand waiting a period of time before announcing, but I don't understand why she pretended it was some big mystery. Was she pretending?

As someone raised by addicts/alcoholics, my mind actually goes to a pretty dark place here. It's no secret Maci loves drinking. Was she just putting off the announcement so she could further drink and party?