I am on birth control and have pcos. i started with my periods 4 days back and have been on the pills regularly. how do i skip my period next mnth?

Maybe: Bcp can be taken in a continuous fashion, skipping the placebo pills, and only using them every 2-3 months to have a menses. But everyone is different, and some people can have some very irregular bleeding doing this. It works best after being on a pill the usual way for a few months, then starting an extended regimen. But if irregular bleeding sets in, it's time to take a week off then restart.

Extend the cycle: It's possible to extend your cycle length by taking the hormonally active pills for longer than 21 d. Many pills have 21 days hormone pills and 7 placebo/reminder pills.You can take 42 63 or 84 pills before taking placebos (and can then take the placebos for 4-5 days). This increases the risk of breakthrough bleeding, but can extend the cycle there are pills that are packaged for extended cycling.