Did you know the vast majority of drug trials that take place on rodents, only take place on male rodents instead of females? So yes, you guessed it: gender biases exist not only in the human world but also in the animal world.

Disclaimer:

I’d like to make it clear that I’m not supporting animal testing. Instead, I want to raise awareness of the lack of testing on female rodents and how this has implications on drugs that are prescribed to women, and the fact that the side effects are unknown. Before researching this, I was completely unaware of how prescribed drugs can influence women more than men. I think it’s important to be aware and understand when women take prescribed drugs, they are at more of a risk of having worse side effects than men.

Why aren’t female rodents used?

Researchers have previously stated female rodents’ short reproductive cycles influence the reliability of their results – female rodents’ reproductive cycles are every four to five days.

So yes, what these researchers are essentially saying, is that in the animal world and the human world, females are ‘too hormonal’ and therefore will not be catered for.

I am so tired of hearing that phrase. So what if women are ‘too hormonal’? You need to accommodate for women, and just because you are too ignorant or lazy to research does not give you the right to use the phrase ‘women are too hormonal’ as an excuse.

Why is this so important?

As a result of these researchers’ utter ignorance, they are neglecting significant information about hormonal shifts and how this influences medicine, as detailed by the neuroscientist and Professor Dr Rebecca Shansky, who further states:

“The excuse that I would hear over and over again is that the estrous cycle [a mouse’s menstrual cycle] would just make the data too complicated”.

Dr Shansky has been researching the repercussions of excluding female rodents from scientific trials for multiple years.

Dr Shansky’s research is detailed in her 2019 article in the journal ‘Science’ and has been influential in starting a conversation about the exclusion of female rodents.

Dr Shansky’s research

Dr Shansky notes in her research that female rodents’ levels of estrogen vary. So for example, one day the female rodents’ estrogen levels might be high one day and then the next day they might be low. Consequently, some researchers argue that due to the varying estrogen levels “you couldn’t possibly understand anything about the brain or physiology or the effects of the drug in a drug trial”.

However, it should be noted that males of any species, regardless of whether they are mice or men, have fluctuating hormones too. Some researchers ignore this fact as a result of the “myopic focus on female hormones” as Dr Shansky comments.

This complete neglect is from the “longstanding gender stereotypes that essentially, male is the norm and female is deviation from that” as Dr Shansky notes.

The Implications

There is a famous example to cite as a result of the exclusion of female rodents in drug testing: the sleep drug ‘Ambien’. This drug was tested on male rodents and then once passed, it was then tested on male humans in clinical trials. However, once this drug was then prescribed, it influenced women differently because female bodies have a slower metabolism rate than men.

Dr Shansky explained in her research that Ambien was supposed to work by taking it before you sleep and then when you woke up in the morning it would be out of your system. Instead, when women took Ambien, they would feel the effects of Ambien still in the morning.

Ambien is just one example of how women suffer different side effects from men, as a result of the lack of testing and testing biases.

What’s changed since this information has come to light?

Since this research has been revealed about the exclusion of female rodents there have been some laws put into place in varying countries. These rules essentially call for researchers to include and test both males and females in animal trials, instead of neglecting female animals.

However, since these rules have been put into place, Dr Shansky notes there are still grey areas due to the various loopholes that researchers can use. For example, researchers’ funding will not be taken away if they decide to not test on females and instead only use males, even though they initially stated they would test on both females and males. Another example, is that if researchers base their research and findings on previous studies done on only male animals, this means their research can continue on only male animals and therefore have the ability to neglect female animals.

What should you do with this information?

With this information and research, Dr Shansky notes this information is not meant for women to refuse treatment or cause distrust in science and medication. Instead, Dr Shansky notes women should feel that they can speak up and ask questions to their GP and Doctors, so that when prescribed drugs don’t work for women or create problematic side effects, women should tell their GPs so that this can continue conversations and awareness.

Dr Shansky comments:

“Often women aren’t believed when they go to the doctor and explain that they have abnormal symptoms. If you feel that a drug is not doing what it’s supposed to do, speak to your doctor and communicate your experience.”

Even though progress has and is certainly being made, it clearly is not enough. It is important to be aware of this issue, especially if you are taking a new prescribed medication for the first time or are currently on prescribed medication. For more information, Dr Shansky’s research and her paper in the journal Science is widely available to read.