Physical Traits

How Genetic Factors Affect Your Menstrual Cycle Length

Learn about your menstrual cycle length through genetic testing. Find out how to upload your raw DNA file now.

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Could your DNA reveal your Menstrual Cycle Length? Upload raw DNA data to learn more about yourself and genomics science.

As women, there’s a lot we can learn about our bodies to manage our health and wellbeing better. One major area we can discover more about is our menstrual cycles. 

The good news is that there is no such thing as a normal menstrual cycle. What is normal for one person might not be normal for another. For this reason, it’s even more important to discover and track what is “normal” for your body. 

If you’ve been experiencing irregular periods or sudden changes in your cycle, you might be wondering why do menstrual cycles and periods get shorter or longer? What does it indicate about your overall health?

The answers might be found in your DNA. 

Before diving into how your genes might play a role in your menstrual cycle, let’s define a cycle length.

What Is A Cycle Length In A Period?

Your menstrual cycle length is the number of days from the first day of bleeding of your last period to the first day of bleeding in your next period.  This length varies from woman to woman, so there is no “normal” cycle length. 

The average menstrual cycle length is 27-30 days, although some cycles can range from 21 days to 35 days. 

As you may know from biology class, the menstrual cycle is complicated. It is regulated by hormones such as estrogen, progesterone, follicle-stimulating hormone (FSH), and luteinizing hormone (LH) that interact with each other through positive and negative feedback loops. 

Previous research has shown the importance of genes such as the FSHB gene (which codes for part of FSH) in this process: their levels of expression can cause all sorts of reproductive health problems, such as irregular periods

Genetics and Your Average Menstrual Cycle Length 

Let’s dive deeper into how genetic factors affect the period cycle length. In a genome-wide association study of more than 40,000 women, Laisk and colleagues found five statistically significant loci associated with normal menstrual cycle length. The five loci were located near five different genes, some of which are known to play instrumental roles in menstrual cycle regulation (FSHB, PGR, and GNRH1) as well as newly discovered ones (IGF2 and NR5A2).

The IGF2 gene may be important because it stimulates the production of estrogen (which affects the regulation of other important menstruation-related hormones), which ultimately affects how follicles mature. 

As for NR5A2, the gene has been previously linked to age at menarche (or a person's first period). Interestingly, with respect to this gene, those with a specific variant were found to have longer menstrual cycles and tend to be older when they have their first period. 

Unfortunately, the study is limited in that information on the length of menstrual cycles was entirely self-reported (which can be biased). 

Nevertheless, this study is still very useful because it is the largest genome-wide association study on menstrual cycle length so far. Future research using a more accurate way of measuring normal menstrual cycle length and with an even larger sample size would be fruitful.

Using a DNA testing kit can give you some insight into your average menstrual cycle length. Uploading Genetic DNA testing data on Genomelink can offer a full DNA analysis so you can finally learn about your menstrual cycle. 

If you menstruate, discover what your genes say about your monthly cycle length on Genomelink now!

Join now & unlock 300+ unique Traits like this.

100+ are available for free