Crude oil production last month averaged 2.279 million barrels per day (bpd), up 0.4 percent from September.
In response, Pemex said it had expected the downgrade since Aug. 25.
Losses for the quarter widened nearly 62 percent to 84.572 billion pesos (US$5.388 billion) from 52.226 billion pesos a year earlier, Pemex said in a statement.