Can I accidentally make a phone call from my watch while I'm sleeping?

I've had my Watch for about 3 mos. now and I've not had any issues with sleeping with the watch on, as I do use the sleep tracker function. This morning at 1:50 AM, I received a frantic call from my mother saying that she had a missed call and a voice message from my number. The VM is about 5 minutes long and she can hear people talking, thought it was me... (Turns out my daughter and her friend were up at that time.) It wasn't me as I was sound asleep at the time. I looked at my phone's recent call activity and sure enough, there was an outgoing call to my mother's phone at 1:42 AM, lasting roughly 5 minutes. My question is, I sleep with my Watch on... Could I have pressed a button or combo of buttons while sleeping, causing my Watch to accidentally dial her number? Her phone number was the last one I had called before going to bed last night... Is there like a redial function on the Watch? I've been wearing my Watch for the past 3 mos. to bed and have never had this happen before. I tried this morning to make the Watch redial my mother's number by pressing the buttons in various ways and numerous times, but I can't get it to redial the last number on my phone. I want to make sure I know what happened here because I would hate to make an involuntary habit of dialing my friends and family at all hours of the night! Any help or suggestions is greatly appreciated!