Post-Pill Amenorrhea

When you stop using hormonal birth control, particularly if you've been having regular bleeds while using the contraception, you might expect that you'd get a natural period about 28 days after your last one, a "typical" menstrual cycle.

But, if you don't.... many doctors will tell you that it's normal to not bleed for three, six, or twelve months after coming off birth control, and therefore you should just wait and see what happens.

This is not supported by evidence. If you don't have a period by about six weeks (or definitely by two months) after coming off birth control, it is an important diagnostic signal - it is likely that there is an underlying issue that was masked by the pill, and it's time to investigate.

If this is the case for you:

• Click here for info about what to test

• If your doctor doesn't have the specialized knowledge to interpret these results, I offer personalized consults to help you understand your bloodwork

Digging deeper: What we know about "post-pill amenorrhea"

The idea of "post-pill amenorrhea" was first suggested in approximately 1966. There were a number of papers written about the condition in that era. It was noted that the relationship could either be "causal" - that is, the amenorrhea is caused by the pill, or "casual" - that something else leading to amenorrhea happened during the time when the pill was being taken. This is what we would today call "correlation", and in the vast majority of cases, I believe this is the most accurate descriptor of what's going on.

We cannot know what is happening with natural menstrual cycles while someone is on the pill. Either the pill causes a monthly bleed during the placebo week, by design, or the pill is taken continuously and therefore no bleed is expected.

So there can be behaviors or diseases that impact the menstrual cycle when someone is on the pill that we are unaware of because the pill does not allow for any understanding of what the natural menstrual cycle is doing.

(Although if you were getting a bleed on the pill and that bleed lessens significantly or stops over time, that is a strong reason to assess what might be going on.)

There are three studies in particular that lead me to these conclusions. Which are neither new, nor my own. In a paper published in 1981 called "The fallacy of post-pill amenorrhea," Archer and Thomas review studies from that era as well as the endocrinology (how the hormones interact) and conclude:

"It appears at the present time that amenorrhea following the use of oral contraceptives should indicate only the preceding temporal use of exogenous steroids without implication as to a cause of the amenorrhea. Investigation should be aimed at determining the underlying cause of the amenorrhea."

Correlation vs. Causation. While it's easy to assume the pill "broke" your cycle when it doesn't return right away, the pill was simply acting as a placeholder. The underlying issue (such as HA, PMOS, hyperprolactinemia, POI, thyroid issues) was already present. (Figure created by chatGPT.)

#1: Study of hormonal changes within one week of stopping birth control pills

In this study, by Van der Spuy et al. (1990), users of three different dosages of birth control pills were studied, along with 14 normally cycling controls not taking any outside hormone preparations.

Summary: By 7 days after stopping the pill, FSH and LH had normalized, and probably estradiol as well, suggesting that cycles would be normal without "post-pill amenorrhea."

You all know that I love digging deeper and really understanding what's going on, so if you want to read more keep going... if not, pop down to the summary of the next study by clicking here.

In this study, each person had multiple hormone tests performed to assess not only levels of hormones, but look at the pulses of the gonadotropins FSH (follicle stimulating hormone), and LH (luteinizing hormone).

Controls had hormonal testing one day between day 2 - day 11 of their menstrual cycle.

Those taking the birth control pills took the pills for 21 days of pills, then had hormonal testing on the first day of the placebo and then again on the last day (day 7).

Day 1 post-pill results:

FSH and LH were suppressed below the level of detection of the tests.

(This points out that it is likely not useful to test FSH and LH while someone is on birth control pills.)

Day 7 post-pill results:

The results on day 7 of placebo (7 days after the last active pill) were markedly different. The FSH and LH levels were the same as in the normally cycling controls, and did not depend on the dosage of birth control pill used.

The next analysis in this same study digs even deeper.

Both FSH and LH are secreted by the pituitary gland in response to pulses of gonadotropin releasing hormone (GnRH) released by the hypothalamus. In the study, levels of FSH and LH were tested every 15 minutes for 8 hours. From those data, you can count the number of pulses and how large the pulses were ( the amplitude - basically how much higher the peak was than the lowest point).

Day 1 results:

The day after the last birth control pill, there were no detectable pulses in either FSH or LH.

Day 7 results:

By day 7, however, both the pulse frequency (how often they happen) and amplitude (change in FSH or LH levels) were similar to the controls.

Estradiol...

Estradiol is most useful for telling us about follicular growth. Before follicles start growing (and when someone has HA), estradiol levels are at a baseline of about 30-40pg/mL. When a follicular wave is occurring, that is, there are follicles growing and maturing, estradiol levels get quite a bit higher.

In this study, there is one notable conclusions as far as estradiol goes, for our purposes - a significant increase in estradiol in those coming off birth control pills between the 1st and 7th placebo day.

The increase in estradiol concentrations during the placebo week for those coming off the pill are suggestive of the beginning of a normal follicular growth pattern.

In fact the authors mention that extending the placebo time by 2 days has been shown to lead to ovulation and strongly recommend against that practice if one is using birth control pills for contraceptive purposes.

Conclusion from Van der Spuy et al.:

1. Any lingering effect of birth control medications on the follicular growth process is minimal within a week of stopping the pill. There is NOT an ongoing impact of having been on birth control pills on three of the major control hormones in the menstrual cycle.

   
   

2. If you want to test your natural hormone levels after coming off birth control pills, you will get a reasonable estimation by taking those measurements one week (or longer) after your last active pill.

#2: Study of ovarian activity before, during, and after birth control pills.

Archer et al. (2009) performed another key study that followed 58 subjects to document ovulation in a natural cycle, then ovarian activity during 3 months on continuous birth control, and finally, ovulation after stopping the pill.

Summary: Almost all the normally cycling women who took birth control pills for three months ovulated again by 21 days after stopping the pill. Again, no indication of post-pill amenorrhea.

Lots more info below, or skip to the next study summary here.

Subjects were required to have regular 24 to 32 day cycles for three months prior to the study. On their pre-treatment natural cycle, ovulation was confirmed by a blood test with progesterone > 5 ng/mL. Birth control pills were started on the next menstrual bleed, at which time participants started a regimen of 3x/week transvaginal ultrasound scans to look at follicular activity, as well as bloodwork to measure FSH, LH, estradiol, and progesterone until post-pill ovulation was confirmed by ultrasound and progesterone measurement.

Ovulation was inhibited in all of the subjects for the duration of the pill usage.

The hormone data presented were a little strange. The authors reported "the median of the maximum values" assessed during each phase of the study, and unfortunately included the data only in graphical format, not numerical (which is a truly awful way to present data). They also don't present numerical data for ovulation after completion of the medication, only a description. However, we can still draw some conclusions.

The data presented were as follows:

• FSH - fairly similar before and during the three months on the pill, increased afterwards

• LH - possibly on the low side before the pill, somewhat suppressed for the three months of birth control pills, increased afterward

• Estradiol - normal before the pill for a mature follicle, suppressed for the three months of birth control pills, increased afterward

• Progesterone - normal before the pill for post-ovulation, suppressed for the three months of birth control pills, lower than normal afterward

My conclusions based on these hormone levels:

1. FSH and LH both rebound to normal (or higher) after three months of the birth control pills.

2. Both before and after the pills, high estradiol levels indicate good follicular growth and mature follicles. Estradiol levels in the first post-pill cycle may be somewhat higher than normal.

3. Progesterone levels in the first post-pill cycle indicate ovulation but may be somewhat lower than normal.

Ovulation after completion of the birth control regimen was documented to occur by day 21 in 36/37 participants that completed the regimen as specified. The one person who ovulated later had a previous medical history suggestive of PCOS. Among the remaining participants (some of whom had not taken the pills every day as prescribed, all had ovulated by 37 days after the last pill).

Conclusion for Archer et al.:

1. There is no indication that amenorrhea is normal or to be expected after taking birth control pills.

2. There may be some small irregularities in the first post-pill ovulation, suggested by higher LH values, higher estradiol values, and lower progesterone values.

   
   

#3: Study assessing the time to return of cycles after one year on birth control pills.

I love when researchers answer the exact question we are curious about! Davis et al. (2008) studied how long it took before having a first post-birth control pill period (or getting pregnant), for 198 subjects in a longer term trial of continuous birth control pills.

Summary: It is not "normal" to take 3+ months to resume menstruation after taking birth control pills.

• 25% of participants had their first menstrual bleed by 29 days after the last birth control pill (typical ovulation timing)

• another 25% had their first menstrual bleed by 32 days after the last pill (pretty typical ovulation timing)

• the next 25% had their first bleed by 36 days (ovulation ~one week later than typical)

• 15% by 45 days (ovulation around a month after stopping the pill)

• 5% by 60 days (ovulation around 6 weeks after their last pill)

• ONLY 5% were without a bleed by 60 days after their last pill

  
  

This study was a follow-on to a phase III trial of continuous ethinyl-estradiol/levonorgestrel pill. The average duration of pill usage was 349 days, so almost a year - a much longer term than the previous studies we discussed. 198 subjects agreed to participate in a follow on study and monitor for menstrual bleeding (and/or pregnancy) after stopping the oral contraceptives.

The vast majority had their first bleed at around one month after stopping the pill, which is what you would expect if hormones were back to normal fairly quickly, as the studies discussed above suggest. The above studies also suggest that these cycles were likely ovulatory, although we do not know that for sure.

There was no relationship between time to return of periods and length of time of no period while on the continuous contraceptive.

Summary

The Post-Pill Timeline. The data show hormones rebound within the first week, and the vast majority of periods resume within 36 days. If you cross the ~60-day mark without a bleed (or ~45 days without ovulation), consider it your cue to investigate rather than wait. (Figure created by chatGPT.)

Long-term amenorrhea after taking oral contraceptive pills (or probably most other hormonal contraceptives aside from Depo-Provera injections) is unlikely to be related to having taken the pill. There is probably another condition causing the amenorrhea, and hormones should be tested (here is a link describing what to test).

The possible conditions include:

• hypothalamic amenorrhea (REDS / hypogonadotropic hypogonadism / female athlete triad)

• hyperprolactinemia (elevated prolactin levels)

• primary ovarian insufficiency (more commonly termed premature menopause)

• PMOS (formerly called PCOS)

• abnormal thyroid

The good news is that most of these conditions (unfortunately, excluding POI) have effective treatments that can restore or improve your cycles. Knowing what's actually going on is both empowering and actionable.

Dismissive advice like 'Just keep waiting,' 'Go back on the pill,' or 'It's normal to not have a period after birth control' is simply not supported by the evidence. You deserve answers, not a waiting game.

If you want to speak with someone who has years of experience in diagnosis, you can book a quick chat (or longer consult) with me.

Want to help change how the medical world understands missing periods?

If you are navigating amenorrhea, consider joining the REVEAL HA registry study. We are hoping to gather 10,000 participants from all over the world to improve research and care, and participation can include bloodwork. You can check your eligibility at noperiod.info/REVEAL.

(Note: AI used for editing suggestions and figure creation only.)