U.S. doctors online nowAsk doctors free
Portland, OR
A 25-year-old female asked:

I have always had irregular periods since menarche (age12). now i'm 25. last few cycle lengths were 36,35,33,40,33,32,42,39,39,39,34 days. should i be concerned about this? which day of my cycle should i take my first pregnancy test,if i am planning?

2 doctor answers4 doctors weighed in
Dr. James Ferguson
Pediatrics 48 years experience
It happens: Some women will opt for BCP's so they can get predictable cycles.From the intervals listed it would be reasonable to wait until 60 days out for a urine pregnancy test if trying. You could wait longer & they are relatively cheep.
Created for people with ongoing healthcare needs but benefits everyone.
Dr. Gurmukh Singh
Pathology 51 years experience
3 weeks after sex: Conception occurs within day or so of the sex. It takes about 3 weeks for the embryo to make enough HCG for a positive pregnancy test. Blood test may be done a day after a missed period. Home pregnancy tests should be done 4-5 days after the missed period. If the result is negative repeat the test in 4-5 days. Use first morning urine and follow instructions for the test carefully.
Created for people with ongoing healthcare needs but benefits everyone.
Last updated Aug 29, 2020


Content on HealthTap (including answers) should not be used for medical advice, diagnosis, or treatment, and interactions on HealthTap do not create a doctor-patient relationship. Never disregard or delay professional medical advice in person because of anything on HealthTap. Call your doctor or 911 if you think you may have a medical emergency.