Wrists take a lot of stress in American yoga. The wrist anatomy doesn’t exactly allow for stress all the time. Lots of down dog, plank, and chatarangas while collapsing into your shoulders and wrists from being overstressed and under stretched will do that. If you don’t do some at home wrist stretches with your vinyasa practice, you could be collapsing rather than lifting and strengthening your wrists. Counter-stretching is particularly important for the hands, since they are so sensitive and are used heavily in modern society (typing, handshakes, etc.). You know that rule the more you use something, the faster it wears out? Well, the wrists contain some of the most intricate neural-muscular connections because they allow for incredibly fast interaction between the fingers and the object(s). Arthritis often occurs first in the wrists and carpal tunnel is not uncommon.
That being said, yoga can be extraordinarily beneficial for your wrists if you are mindful and take breaks when you need to. Standing on your wrists and hands is generally very good for them, as it released the pressure in the small bones that you can see here:

There are 7 bones in the middle of the wrist, connected by the ulna and radius on one side and the metacarpals and fingers on the other. Two major nerves flow from the thoracic (middle) spine into the hands, the radial and ulnar nerves. The radial nerve flows into each finger except the pinky and is the main source of nervous energy for the thumb and gripping. The ulnar nerve flows mostly into the pinky and ring finger, but also slightly into the middle finger. Check it out:
The ligament arrangement of the wrist might be the most complex part of the joint, creating extraordinary flexibility and mobility at the same time as strength, and durability. It is mostly a web of connections that need to be stretched every so often, or they will start to harden and erode with overuse. Too much typing without stretching will leave the ligaments tense and the muscles shorter.

Pressing into the L of the radial nerve to lift can help to ensure that you are creating strength and space between the ligaments, rather than compressing them and eroding them. Its pretty easy to overuse the wrists, so find some ways to decompress and stretch them; standing on the hands, pressing the tops of the wrists into the floor while flexing the wrist, or even pulling the fingers back towards the arm then curling them into a fist always with the thumb untucked.
Happy wrists mean a happy yoga practice. Keep stretching those wrists in the few minutes before class, bring mindfulness to lifting through the forearms in down dog and plank. Take breaks as often as you need while ensuring that you are building strength. Don’t forget to spread through the fingers when you can 🙂