A while ago there was a thread where where the OP stated that they disliked the use of 'pregnancy/ baby brain' as an excuse.
Frankly I was already noticing new and really bizarre things happening since getting pregnant but could not be arsed to defend my right to say that pregnancy brain is a very real thing IMO.
After the last couple of weeks (now 24 weeks), I fully reserve my right to use it as an excuse for funny behaviour or forgetfulness etc...
Yesterday I went out and took my digital house phone with me. I didn't realise I had done it till I was out and then promptly forgot about it for the whole day until DH heard it ringing in my coat pocket.
I keep forgetting at least one thing at home when going out and having to go back for it, or putting items in the fridge or airing cupboard that definitely don't belong there (such as tins of sardines or my keys) 
I forget what I am going to say while I am mid sentence and end up having to explain that I just instantly forgot while talking (very annoying)
So bollocks to you if you haven't experienced 'pregnancy/ baby brain' and think it is just an excuse, because it can actually be very tedious. Especially when you end up spending a crap load of time looking for something because you can't remember where you put it, very regularly.