determining pregnancy- irregular cycles.

[anonymous-user]

  
      PLEASE CLARIFY THIS.
     Do htp results vary according to a women's cycle?
     I have read that they are accurate:
     3 days after a period is due (this can vary from woman to woman)  
     and i have read that they are accurate:
     @ 17 days after conception....
     WHICH IS TRUE??
    
     If the later is true, that would imply a woman with an irregular
     cylce could test early... if the first is true, then a women with
     an irregular cycle is all but lost!
      My lmp began feb 14th.. I am often somewhat irregular but average
      28-31 days.  Today is day 32, four days past a normal woman's cycle.
      I went for a lab (urine) test yesterday
      which was Negative... I took an HPT today, also Neg.
      Am i testing too soon?  Date of conception would have been 3/1.
      Which means, I am 17 days past conception... but Not neccesarily three
      days late.  Which is why i ask you to clarify the above.
      Also, i took my First AM urine and refrigerated it, then took the
      hpt later.  Can temp affect the test?
        
      Thanking you in advance for your time!!!!!!

[hfhsmdrcs]

_
Dear Questioner:
There is a standard menstrual cycle: it is 28 days long and ovulation occurs on the 14th day. Whenever any reference is made to tests being done "one day after the missed period", the ASSUMPTION is that the cycle is this perfect, textbook-defined cycle. Real women are rarely like this.
In reality, for most women, ovulation has a range of approximately 3 days from menstrual cycle to menstrual cycle. Furthermore, the second half of the menstrual cycle can be as short as 10 days and as long as 16 days, within a 28 day long cycle.
Ovulation occurs! The egg is fertilized within 1 day. The fertilized egg resides in the fallopian tube for 3-5 days. It then moves into the uterus and by the 7th day after ovulation it is attaching into the uterine lining. As the early embryo grows in the uterine lining, it secretes hCG into the blood stream of the woman to signal the corpus luteum in the ovary to continue to make progesterone.
Depending on how much hCG signal is secreted determines how soon the blood level is high enough to be detected by a blood pregnancy test. How much of the hormone is available to be cleared into the urine determines how quickly a urine pregnancy test becomes positive.
Working rules: a blood pregnancy test that is negative 14 days after ovulation and a urine pregnancy test that is negative 17 days after ovulation is giving reliable information: the lady is not pregnant. Tests in ladies that are pregnant may be positive earlier than these time points, but a negative test at an earlier time point is not reliable.
When a woman has an irregular cycle and does not know when she ovulated in a given cycle, there is no scientific way to know when to do a test. My advice, wait 3 days beyond the longest cycle length (from what you describe, that would be cycle day 34.
I do not know if temperature affects the test kit which you used. Temperature does change many test kit reactions. If the test kit instructions request a fresh urine sample, than the bacterial action on proteins in the urine and refrigeration must be assumed to influence the test result.
Keywords: urine pregnancy test, irregular cycle
This information is provided for education purposes and is not a medical consultation. If you have specific questions, please speak with your healthcare provider.

[mz_truan]

A related discussion, irregular periods..pregnancies.. how do i know when to take a pregnancy test was started.