Can I stop pumping during the night?

My 4 month old baby girl sleeps wonderfully through the night. I nurse her at 8pm, put her in her crib at 830, and then she wakes up around 6am. The only problem is, I get waken up around 1am each night because my are engorged and sore so I pump. This is getting so annoying I want to stop but I really don't think I can go 10 hours without expressing milk. Someone suggested staying up until midnight and pumping then, and go to bed after. But I need more than 6 hours of sleep. I go to bed at 9:30, pump at 1:15am or so, and then go back to sleep until 6. Any suggestions to stop this? I don't want to do this until she is weaned approaching 1 year of age!