An Enticing Headline: The Pill Reduces Ovarian Reserve

kali's picture

As integrative medicine practitioners, we know that anything you put into or on-to your body has some effect (large or small) on the cellular environment and the way the organ systems function.  One question I frequently get asked is whether the oral birth control pill (OCP) has an effect on long-term fertility.  While my answer has always been that it depends on a number of factors, underlying conditions, and length of time a woman has been off of the OCP before trying to conceive, some new research is shedding light on the OCP’s effects on ovarian reserve and causing waves in our online community.


Most available evidence on the Pill’s effect on fertility is reassuring – the majority of good quality studies show that after stopping the Pill and as cycles revert to normal, pregnancy is likely for most healthy women.  One study done in 2009 showed that, in nearly 60,000 pill users, those who stopped had a 21.1% chance of pregnancy in their first cycle, and a 79.4% chance of pregnancy in the first year after Pill cessation.


This new project in Denmark was launched to investigate the reliability of preconceptual lifestyle and biological factors as predictors of fertility.  So far the authors have released some data regarding the effects of OCP on markers of ovarian reserve that has been making some sensational headlines.


The term “ovarian reserve” is being used to describe the ability of the ovaries to produce follicles, and thus produce mature eggs that have the potential to be fertilized.  It is most accurately assessed at present by two different tests: an AMH (anti-mullarian hormone) blood test, and an AFC (antral follicle count) done during a vaginal ultrasound.  The fertility world considers these two tests together as the best indicator of ovarian reserve, or remaining fertility potential, in a woman.  As we age, ovarian reserve declines at a different rate for every woman, depending on a number of known and likely many unknown factors.


The Danish study looked at 833 women between the ages of 19-46, asked them about prior OCP use, and measured AMH and AFC.  Almost 30% were former Pill users.  They found that AMH was 19% lower in Pill users than non-users, and AFC was 16% lower in those who had used the Pill.  Also of note, the ovarian size was reduced by between 29-52% in Pill users.  Dr. Birch Peterson who headed the study says she expected to see some effect of the Pill but that researchers were surprised at the size of the impact.  She has also been quoted as saying she is unsure whether these changes are permanent.


So what you might get from the headlines is that the Pill is reducing ovarian reserve, or accelerating ovarian aging.  But you’d be making a jump that the media wants you to, and the research doesn’t support.


Here is where the headline doesn’t tell you the full story – the study researchers suggest retesting AMH and AFC 3 months after coming off of the birth control pill, because they believe that this effect of lowered ovarian reserve parameters is not permanent.  Dr. Birch Peterson said “the Pill is unlikely to change the ovarian biology of egg depletion – but it certainly changes the appearance of the ovaries and the secretion of AMH” and that women who have been on the Pill “are now advised that their ovaries may look old, with small volume, few small antral follicles and low levels of AMH” but this, she adds, may not necessarily reflect her future fertility status.


As with all research – reading the headlines doesn’t tell us the full story.  Even the research itself cannot.  The best take-home message from this news is that if you’ve taken the Pill before, your AMH, AFC and ovarian size may be lower than expected, especially if you recently stopped taking it.  But three things to remember: 1. The low numbers may not be accurate in predicting your future ovarian reserve, 2. The effect may not be permanent, 3. There are many natural ways to slow down biological aging, and increase the quality of the remaining follicles and oocytes to increase the likelihood you get pregnant naturally or with IVF.


Speak to your Acubalance practitioner any time you read a headline and have an emotional reaction.  We’re well versed in how to interpret research, and can give you a more accurate take home message of what a study really tells us.  And attend one of our free fertility seminars to find out how you can slow the biological aging of your egg cells, and improve your fertility potential naturally.



In health,


Dr. Kali MacIsaac HBSc, ND

Naturopathic Doctor