Michelle asked
I switched the time at which I took my birth control pill from when I go to sleep to when I wake up. I wake up at the same time every day and don't always go to bed at the same time every night, so I thought it would be a reasonable switch. I switched times at the beginning of a new pack.
I was expecting to see a little spotting here and there but about halfway through the pack (about two weeks after initial time switch), I got my period, and this was no spotting, it was a full-on, heavy period. It's been going on for four days now and after this week is the week of placebo pills when I normally get my period.
Is that normal? Should I be worried? What should I do?
Answer
Breakthrough bleeding is relatively common upon starting birth control pills and when there is any change in how you take your birth control pills, including a change in the time you take the pills. As you mentioned you are starting at a new time (morning vs. evening), this could be the reason you are experiencing mid-cycle bleeding.
Mid-Cycle Bleeding On Birth Control Pills
Though a simple change from evening to morning dosing seems fairly innocuous, it likely is playing a big factor in the breakthrough bleeding you are experiencing.
We commonly think of hormone fluctuations in the time frame of 28 days, the average time of one menstrual cycle. However, many studies show that hormone levels, especially estrogen, can fluctuate greatly throughout a 24 hour period. Estrogen levels tend to peak in the morning and decrease in the evening. Below is a graph from one study that illustrates this point:
Source: Diurnal rhythm of free estradiol during the menstrual cycle
Your body may have become used to the evening dose of hormones you were taking and now is responding to the lower evening estrogen levels.
Most studies show that changes to your birth control regimen will cause a variety of symptoms including:
- Breakthrough bleeding (which can be heavy)
- Spotting (lighter bleeding)
- Headaches
- Breast tenderness
- Mood changes
In fact, having bleeding changes after an alteration to your birth control pills happens to a majority of individuals. The prescribing information for Junel, a popular birth control pill, states over 85% of women experience unscheduled bleeding and/or spotting at some time during their cycle after initiating therapy.
The good news is that unscheduled bleeding should decrease with each cycle, so expect this to get better. The prescribing information for Yasmin states the following:
"Irregular bleeding may vary from slight staining between menstrual periods to breakthrough bleeding, which is a flow much like a regular period. Irregular bleeding occurs most often during the first few months of oral contraceptive use, but may also occur after you have been taking the pill for some time. Such bleeding may be temporary and usually does not indicate any serious problems. It is important to continue taking your pills on schedule."
Nevertheless, if you continue to experience breakthrough bleeding into your next cycle, you should consult your doctor for evaluation. It is important to rule out other factors that could cause breakthrough bleeding such as:
- Infection
- Drug/supplement interactions
- Underlying diseases
