4th day of the break and still no withdrawal bleed?

Hi,
Welcome to ehealthforum,
If you have been regular with taking the pills on time, then chances of pregnancy can be ruled out. The delay in periods could also be attributed to stress or to hormonal changes due to sexual activity close to your expected period time. Sometimes you can have missed period while being on oral contraceptives. Start with the next pack of pills on time if you do not suspect pregnancy and get your periods by the time you finish with placebo pills. If you suspect to be pregnant or are having symptoms suggestive of pregnancy, then consider visiting your gynecologist for further examination and blood HCG test to confirm/rule out pregnancy before starting with next pack of birth control pills.
Take care.