Bleeding from the morning after pill
Yes it counts. Actually it's not usually a period but rather just bleeding or spotting like you had.
It's not wise, but it is necessary. Go ahead.
Is light period on pills same as a missed one?
It is only counted as a missed menses if you have NO bleeding at all. A light or very light period is still a period on the pills.
Rarely, a very light period can be associated with a pregnancy if you missed more than one or two pills in a month.
Are low dose (20 mcg) pills less effective?
If you don't miss pills, the 20 mcg dose is as effective as the 35 mcg dose. The lower dose does give you more of a chance of breakthrough bleeding. You are still protected from pregnancy but more likely to spot. If you try them and don't have any breakthrough spotting, then you should do just fine and would not be more likely to get pregnant.
Scanty or light periods on the pill are common and shouldn't cause worry. Sometimes you skip periods altogether.
Stopped pills because spotting, now no withdrawal bleeding
Most of the time you have some withdrawal spotting but not always. Since you have been on continuous pill therapy, the lining of the endometrium is probably very atrophic (thin with little tissue). There was enough thinness to spot but now that you are off the pills, there is not tissue left to slough and the lining is starting to get more stable under your own body's estrogen. You will probably need to be off the pills for a month or so to have a normal cycle.
Another alternative for the spotting on the pills is to resume the pills but take an estrogen supplement to "stabilize" the lining of the uterus. I'm assuming you are not pregnant. Check that out if you need to.
Period month after month and still pregnant?
This is rare but some women swear they had cyclic bleeding while they were pregnant. This usually is not reported past the first 4 months. As best I can tell, these cases have never been documented well and are thought to represent bleeding rather than menses except in the instances you mentioned.
Failure rate of birth control pills
From scientific studies where individuals have been highly motivated to comply, the pregnancy rate for the pills is 0.1% or 1 per 1000. Overall, however, the pregnancy rate in actual use is 3% or 30 per 1000. You are correct that this is a large difference.
Source for these numbers is Speroff et al, Clinical Gynecologic Endocrinology and Infertility, 5th edition, 1994, p. 689.
Breakthrough spotting on continuous pill therapy
Breakthrough spotting and bleeding on continuous pill therapy happens to almost everyone sooner or later. Rather than switch pills, I would discuss with your doctor whether or not you could come off of the pills for a week (to have a withdrawal bleed) or even one month (to have a natural cycle withdrawal bleed). Then resume the pills. This is more likely to prevent further breakthrough bleeding for awhile.
Can you have a pill withdrawal period and be pregnant?
If you were to become pregnant on birth control pills, a normal withdrawal period would not occur because progesterone production from the corpus luteum gland on the ovary overrides the drop in progesterone from finishing the active pills. Occasionally a woman could have some spotting while pregnant but usually it isn't a full period.
Effect of diarrhea on pill effectiveness
No, a single episode of loose stool would not have altered the pill's effectiveness.
Continuous diarrhea for 1 -2 days
In this case you don't need backup. If you do develop continuous diarrhea for 2 days, continue your BCP's and use additional backup while the diarrhea persists and for 7 days after it has stopped.
Thyroid assessment on birth control pills
Sounds like you are describing pretty severe hypothyroidism. This degree of thyroid dysfunction is unlikely to have been due to your OCP's. It is possible with the old tests of just measuring T4 that a low T4 (hypothyroidism) off pills could have a higher value when on pills, but you are still low on thyroid. We used to measure T4 and T3 while on birth control pills because of these false readings. Now a serum TSH (thyroid stimulating hormone) is accurate whether or not you are on pills.
You need to have your TSH measured now.
Breakthrough bleeding after starting a cycle late
You are protected now from pregnancy since you have been back on the pill for more than a week. The breakthrough bleeding won't stop until your next period and sometimes it continues into the next cycle. It should be over after that.
Basal body temperatures (BBTs) as backup to pills
That's an interesting question I don't think I've ever had asked before. I'm not sure, but I suspect the progestin in the pill would alter the early temps to make them higher. On the other hand, if you had a breakthrough ovulation on the pill it could well show a biphasic curve. If you took BBTs for two months and they were flat, I would quit taking them.
The failure rate of BC pills is about 1-3% overall but if there is perfect use (no pills missed) the failure rate is only about 3/1000. It seems if you are compulsive enough to take BBT temps, it's unlikely you would miss a pill. It therefore seems to be a bit of overkill to take BBTs while taking the pill.
