俱舍論頌疏論本 15.82

15.82

釋曰：於欲界中住中有位，容有能造二十二業。謂中有位、胎內五位、胎外五位，中有能造此十一位定不定業故，名二十二。

The explanation says: Staying in the intermediate existence in the Desire Realm, one can produce twenty-two karmas. That is, the stage of intermediate existence, the five stages inside the womb, and the five stages outside the womb: because the intermediate existence can produce definite and indefinite karma for these eleven stages, they are called twenty-two.