Your girlfriend is likely crying easily because her progesterone and estrogen levels have plummeted right before her period starts. This massive hormonal shift directly impacts serotonin, which is the chemical in her brain that helps regulate mood and feelings of happiness.
When serotonin drops along with her hormones, her emotional fuse gets a lot shorter and her brain basically loses its ability to filter out stress.
I have seen this happen with my own partner and it used to really confuse me until I actually looked into the science of it. It is not that she is being dramatic or trying to start a fight. Her body is quite literally going through a withdrawal process.
Before the bleeding even starts, a woman’s body prepares for a potential pregnancy. When that does not happen, the hormone levels that were keeping the uterine lining stable just crash. This phase is usually called the luteal phase. It is a biological roller coaster.
For some women, this just means they feel a bit more sensitive than usual. For others, it can lead to PMDD, which is a much more intense version of PMS where the emotional spikes are actually debilitating.
The drop in serotonin is the biggest culprit for the crying. Serotonin helps us stay calm and rational. When it is low, everything feels ten times more overwhelming. A dropped spoon or a slightly sad commercial can trigger a full breakdown because the emotional regulation part of her brain is essentially offline for a few days.
On top of the brain chemistry, she is probably in physical pain. Imagine having a dull, throbbing ache in your gut or lower back for forty-eight hours straight while also feeling bloated and exhausted. Most people would be a little teary under those conditions even without the hormone shift. Physical discomfort makes it much harder to keep your cool when things go wrong.
If you want to be a solid partner during this time, the best thing you can do is just offer a safe landing spot. Do not ask her “why” she is crying. Half the time she probably does not even know the answer herself. Just knowing that you are there and that you are not judging her for being “irrational” goes a long way.
I started using an app called DuoSync recently. It is a period tracker designed for men that lets you see where your partner is in her cycle.
Download the DuoSync app to grow closer to your partner.
It is also worth noting that if her mood swings seem truly scary or if she feels hopeless, it might be more than just standard PMS. About 3 to 8 percent of women suffer from Premenstrual Dysphoric Disorder. This is a serious medical condition that usually requires a doctor’s help. If she is just teary over a cute dog or a sad movie, that is totally normal.
If she is unable to function or seems like a completely different person, it might be worth a gentle conversation later about seeing a professional.
Most of the time, the crying stops a day or two after the period actually starts. Once those hormones begin to level out again, her serotonin will bounce back and she will feel like her usual self. Just hang in there and be the person who brings the chocolate and the comfort.
FAQ about period emotions
Can hormones really cause such sudden mood changes?
Yes. The shift in estrogen and progesterone is very rapid. These hormones interact with brain chemicals like GABA and serotonin which control anxiety and mood. When they drop, the brain’s “calm” signals get much weaker.
Why does my girlfriend get angry instead of sad?
Irritability is just as common as sadness. Some women experience a spike in cortisol or a different reaction to the drop in estrogen that manifests as a “short fuse” or anger rather than tears.
Is it okay to use a period tracker for my girlfriend?
As long as she is comfortable with it, yes. Using an app like DuoSync can help you be a more proactive partner. It allows you to anticipate her needs so you aren’t wondering why she is upset.
Does diet affect these emotional spikes?
It can. High sugar or caffeine intake can sometimes make the “crash” feel worse. Complex carbs and staying hydrated can help stabilize mood slightly, but they won’t stop the hormonal shift entirely.
When should I be worried about her crying?
If she mentions hurting herself or if the sadness doesn’t go away once her period starts, that is a red flag. Normal PMS should lift pretty quickly once the cycle resets.