### instruction:
If you are a doctor, please answer the medical questions based on the patient's description.

### input:
I HAD AN IUD FOR 6 YEARS, I HAD IT REMOVED AND DECIDED TO GO ON BIRTH CONTROL. SO I HAD MY REGULAR PERIOD APRIL 19,2010. AND I STARTED MY PILLS MAY 2. 2010. I HAD SEX ON MAY 1, 7,8,9. I STOPPED TAKING THE PILLS ON MAY 7, BECAUSE I HAD SEVERE HEADACHES EVERDAY THAT I TOOK THE PILL. I THOUGHT WHEN YOU STOP TAKING THE PILL, IT CAUSES YOU TO HAVE YOUR PERIOD. I HAVE NOT STARTED. AND IM WONDERING IF MAYBE IM PREGNANT AND THATS WHY I HAVENT STARTED. OR MAYBE IM WRONG AND STOPPING THE PILL DOES NOT CAUSE YOU TO START YOUR PERIOD. I AM 33 YEARS OLD AND HAVE 4 OTHER CHILDREN SO I KNOW I AM VERY FERTILE. HOW LONG SHOULD I WAIT TO TAKE A PREGNANCY TEST.

### output:

Hello, Thanks for writing to us. Irregular intake of birth control pills make cycle irregular due to hormonal imbalance. You should take regular pill on proper time to avoid unwanted pregnancy. I suggest you to undergo the home pregnancy test after 2 weeks from last sexual intercourse. Blood test for beta-ChatDoctor is more reliable. Beside pregnancy, reasons of late period and above clinical features could be hormonal imbalance, over weight/ extreme loss, extra mental stress or anxiety, emotional upset, eating disorder, thyroid problem, POD etc. On NEGATIVE test, I suggest her to undergo one USG lower abdomen and hormone test to rule out other underlying causative agent and confirm the diagnosis. Kindly, consult with her local gynecologist and take advice accordingly. She may need to take hormonal pill to induce period. She would control body wt, avoid stress, take healthy low carboy Chat Doctor. Be well and take care.