Menstrual Phase Symptoms: The Complete Guide
The most common menstrual phase symptoms are cramps, fatigue, low mood, headaches, bloating, and back pain. They happen because estrogen and progesterone are at their lowest and prostaglandins trigger uterine contractions, all in the first few days of your period.
The hormones behind your menstrual phase
The menstrual phase begins on the first day of your period, when both estrogen and progesterone bottom out. Without progesterone to hold it in place, the uterine lining sheds. Those rock-bottom hormone levels are why energy, mood, and body temperature dip, and why prostaglandins (the compounds that make the uterus contract) can drive cramps, fatigue, and looser digestion.
- Estrogen and progesterone are at their cycle lows, so energy and mood run quieter.
- Prostaglandins trigger uterine contractions, which can cause cramps and lower-back ache.
- Iron drops with blood loss, adding to fatigue and brain fog.
- Pain sensitivity is higher, so rest and gentle movement beat pushing hard.
Know what your body needs, every day
PhaseBloom turns your cycle into a day-by-day plan for how to eat, move, rest, and care for your skin, so you stop guessing and start working with your hormones.
The most common symptoms and what causes them
Menstrual symptoms cluster in the first two to three days when hormones are lowest and prostaglandins peak.
- Cramps and back pain: prostaglandins make the uterus contract to shed its lining.
- Fatigue and brain fog: rock-bottom hormones plus iron loss from bleeding.
- Low or tearful mood: low estrogen means low serotonin.
- Bloating and looser digestion: prostaglandins also affect the gut.
- Headaches: the sharp estrogen drop is a common migraine trigger.
How to ease menstrual symptoms
You cannot switch hormones back on, but you can support your body through the low.
- Prioritize iron-rich food with vitamin C to replace what you lose.
- Swap intense workouts for walking, yoga, or rest.
- Use heat for cramps and magnesium for muscle tension.
- Protect sleep and lower caffeine, which can worsen cramps and anxiety.
Know what your body needs, every day
PhaseBloom turns your cycle into a day-by-day plan for how to eat, move, rest, and care for your skin, so you stop guessing and start working with your hormones.
Frequently asked questions
When are period symptoms worst?
Usually days 1 to 2, when flow is heaviest and prostaglandins peak. Symptoms typically ease as bleeding tapers and estrogen begins to rise.
Are severe period symptoms normal?
Mild to moderate symptoms are normal, but pain that stops you functioning, very heavy bleeding, or symptoms that worsen over time are worth discussing with a doctor, as they can signal conditions like endometriosis.