Irregular Periods After Birth Control Change: What to Expect?

Question
Hello Dr.
I am 26 years old. I had been using the ortho evra patch since I
had my daughter, 2 years ago. In early November I switched to
Ortho Tryciclen pills. I didn't take them properly (off by
hours...missed dose) so I quit taking them after that initial pack
was gone. I haven't used any birth control since Mid December
after having my period.
I recall that I was on my period December 16th. I am unsure at
this point whether that was the beginning, middle, or end of it. I
cannot remember.
At any rate... I think at this point I am late since my regular cycle
was every 3 weeks. I took 2 pregnancy tests on my own (both
negative) and on Friday (13th) I was given another test at my
doctors office. AGain it read as Negative.
My question is this... is it possible that my period will come but
it is delayed because this is the first time my body hasn't had
hormones in 2 yrs? What is going on?
In the time I didn't use protection I only had sex one time using
the withdrawal method. Just once.
Anyway, I thank you in advance for your thoughts. Kelly-

Answer
If your last period was around December 16, you probably were due for your following period on January 12. Since you stopped the pill, you can't tell how long your cycle actually is. A cycle is considered normal if it is 21-35 days in length. HOwever, it may have changed once you stopped the birth control pills.The best time to take a pregnancy test is seven days after missing your period. You were due for your period on January 12, so if you do not get your period by January 19, repeat the pregnancy test. Sometimes it takes a month or two after stopping birth control pills to regain a regular cycle. Be patient. Don't use the withdrawal method because it does not work at all. There are around 300,000 sperm at the tip of the penis prior to ejaculation. If he tries to withdraw his penis prior to ejaculation, these sperm can be "milked" into the vagina and you can conceive if it is at the correct time of the month. If your last period started on December 16, you probably ovulated on December 29 and could have conceived ONLY if you had sex on December 28,29,30, or 31. A pregnancy test will not show a positive result until 14-21 days later (between January 12-19).