Irregular period and faint positive pregnancy test... was it a miscarriage and/or should I be worried?

I can understand why you are concerned, so let me see if I can also offer some help.

It is unlikely that you experienced a miscarriage, for a few reasons:
1. birth control pills are 99% effective at preventing pregnancy when taken as directed
2. timing is not quite right, as you were expecting your period during this time (and even light spotting and cramping that lasts for a few days would not indicate an early pregnancy). Light bleeding is not a sign of pregnancy, and this occurred before your heavy bleeding, which tells me you most likely were not pregnant. The timing is not right because it takes 10-14 days after ovulation for you to have a period...the same amount of time for a fertilized egg to implant (to create a pregnancy). Any miscarriage at this point would likely feel the same as a heavy period, as there has not been a placenta formed or anything...just the same amount of blood and tissue that either creates a place for an egg to implant OR for the lining to shed during a period.
3. It would not have been implantation bleeding, as this would be a mere "spot" that most women do not even notice, and would be seen after using the toilet and wiping or on your underwear. Implantation bleeding (should be called "spotting") does not last for days; it is a one-time occurrence, and you would have had a more readable positive test. Hopefully you can rule this possibility out.
4. A home pregnancy test is 99% effective at detecting the "pregnancy hormones" once you're period is due, and since a faint line occurred after your bleeding, I would have expected the line to be more substantial if you were pregnant and miscarried. Also, if a woman does have a miscarriage, the "pregnancy hormones" (hCG) do not immediately decrease and can take days to weeks to lower to non-pregnancy levels.

The other possibility is that you may have had a miscarriage, but this is very common for women, and you are not in any physical danger. Most home pregnancy tests do not show even a faint line unless it is detecting some sort of "pregnancy hormone", so this is puzzling. But, it does happen that women are not pregnant and the test shows a faint line; I would advice re-testing if this was not a result you expected. For instance, if you have missed a few pills, or are otherwise doubtful about your "perfect use" of birth control pills, then of course the effectiveness rate goes down, and your chance of pregnancy goes up. In this scenario, here is what you can do:
1. Different pregnancy tests do vary according to their "sensitivity", but all are about 99% effective at detecting hCG once a period is missed (or after it is due). If you still have the test packaging, you can look to see what it indicates: a test with a sensitivity of 20 IU/L will tell if you're pregnant sooner than a test with a sensitivity of 50 IU/L. Just more information.
2. Take another home pregnancy test, and check the results. If it is negative, then your hCG levels are within the normal non-pregnancy range and you should have a normal period next month. If it is negative, there is a very, very slight chance that you could have experienced a miscarriage and your levels went down quickly (not likely, but possible).

The pain you experienced is troublesome, especially if you never had these symptoms before with a period. Abnormal periods are described by heavy bleeding (soaking more than a pad or tampon every 2 hours), bleeding that lasts more than 7 days and extreme pain, so I would think that maybe you experienced an "abnormal period" and you can talk with your doctor about your symptoms (and, in my professional opinion, any time you experience doubling-over pain...call your doctor). I am not sure what your doctor's protocol is for extreme pain during period, especially if this is your first experience, but does not hurt to call and ask.

I hope this has helped; please let me know if I can clarify any information.

Hi Anon - Thanks for writing in and seeking information.
While what you're experiencing may seem off track and unusual, it's very common for women to experience abnormal periods. Some women's periods change for no "apparent" reason, and the change can be: timing during cycle, color (red, pink or brown), duration of bleeding, amount of flow, etc.

As far as the faint blue line, if you've been using the birth control pills as directed it's not likely that this would indicate a miscarriage. Some tests have difficult to follow instructions, and any mis-step in use may result in a wrong result. If you ever do have a clear positive result on a home pregnancy test, be sure to follow up with a doctor right away.

if you continue to have periods that are significantly different (lighter, shorter, irregular), then you can ask your doctor's office for their recommendation. Doctors are usually more concerned with bleeding that lasts more than 7 days, or bleeding that's extremely heavy or painful. Both of these can be signs of a medical condition that needs attention. Otherwise, you may want to try a different brand of pills, as your body does change over time.

Has this information helped you? Do you need any additional information? Let me know if I can help further, and how you're doing now.
Take good care,
Pat