Currently, the only way to record and send a voicenote on WhatsApp is to either hold the microphone icon for the period you are speaking then release the icon when you are done speaking to send, or swipe up from the microphone icon to lock it while you speak and then hit the send button when your done speaking. For either of the methods mentioned there is no room to accommodate possible distractions, if you encounter any form of distraction you just need to cancel the entire voicenote and start recording all over again. WhatsApp is making plans towards bringing that to an end by adding a pause button to the voicenote feature. With this you can accommodate any distraction by pausing your recording and attending to whatever the distraction might be, then returning to your recording. This feature will be a very important addition to WhatsApp and will be welcomed by so many users out there. The pause button might find its way to WhatsApp via a future update. Source Source
