mouthSure, you’re probably already aware of certain physical changes that occur as a result of fluctuating hormones over the course of your monthly cycle, like a high or low level of energy, how much water your body retains or how clear your skin is.

But, did you know your hormones also affect how your voice sounds over the course of your monthly cycle?

Research shows that on some days your voice is deeper and rougher. Other days it’s higher and clearer. Some days it’s monotone. Other days it’s more sing-songy.

Knowing what to expect from your voice from week to week can help you capitalize on your vocal strengths and overcome vocal challenges so you can nail a presentation, win over a job recruiter, record a video voiceover, leave a flirtatious voicemail or simply record a better outgoing phone greeting.

Ready to find out what changes your voice undergoes week to week? Here’s what to expect during your…

Week 1: Deep start, high finish
Day 1 (first day of your period) to Day 7
At the start of your Week 1 (your menstrual week), you speak with a slightly deeper and hoarser voice, according to a 2011 study in the journal PLOS ONE. The researchers chalk it up to high fluid content in your throat membranes due to water retention. However, as your Week 1 goes on, rising estrogen prompts your body to shed this excess fluid and your voice becomes clearer and higher.

Week 2: Higher and more attractive
Day 8 to ovulation (which is Day 14 in a 28-day cycle or day)
As estrogen continues to rise in your Week 2, your voice continues to be clear and you’re using a wider range of notes as you speak, especially higher-pitched ones. In fact, if you’re a singer, you’ll find it easier to hit hard-to-reach high notes on these days compared to other weeks in your cycle.

Additionally, on the days leading up to ovulation (which occurs at the end of this week of your cycle), your voice sounds more feminine, attractive and flirtatious, according to a 2013 study in the journal Hormones and Behavior.

This makes it a great week to tape a new voicemail greeting, leave a message for a cutie, record a voiceover for your latest YouTube video, go on an audition or enter a singing competition.

Tip: When leading a group or when you want folks to pay more attention to what you’re saying, you may want to deepen your voice a bit. A 2012 study published in the journal PLOS ONE shows that low-voiced women are perceived as more competent and authoritative, making people more likely to listen up. Need help deepening your voice? Tuck in your chin toward your neck. This automatically lowers your vocal pitch slightly.

Week 3: Low and monotone
Begins day after ovulation and lasts 8 days (which is Day 15 to Day 22 in a 28-day cycle)
The start of Week 3 signals a steep descent in estrogen and a rise in progesterone–a combination that has you using a somewhat narrower range of notes and having a slightly flatter sound. As progesterone prompts water retention in this week of your cycle, you may notice by the middle to end of your Week 3, your voice gets a bit deeper and throaty like it did during your menstrual week.

Some advice: If you get a big gift or unexpected surprise–like a diamond ring or promotion–remind yourself to sound more enthusiastic and excited since your monotone voice could make you seem a tad unimpressed.

Week 4: Flat and shaky
Final 6 days of your cycle
You can expect more of the same kind of mildly monotone voice you experienced in Week 3. On top of that, due to a sharp plunge in estrogen all throughout your premenstrual Week 4, may find it difficult to reach high notes when singing and your voice may sound a bit shaky, according to a 2001 study in the Journal of Voice.

If you’ve got an important meeting, audition or singing competition where you need to be at your vocal best, skip caffeine–which can make your voice sound even more jittery–and opt for a cup of warm chamomile tea instead, which will calm you, reducing shakiness, and lubricate vocal chords, helping you sound more eloquent and making it easier to reach the high notes you want.