Ask Ms. Vagina Science- Understanding How Menstrual Hormones Influence the Way You Feel

Dear Ms. Vagina Science, 

What causes pregnancy symptoms? What shift in hormones causes the nausea and sore boobs? Is it increased progesterone?  I’m not pregnant, but I’m super tired and run-down, craving weird things, have sore boobs, and my stomach flips out every time I eat. I am nauseous all day. My period isn’t due for a week, but if it weren’t for my period last month, I’d be absolutely convinced I was pregnant. I’m just trying to find some vitamin I might be depleted in, or a hormone that might be going crazy with the full moon? Either way, it’s all so annoying.

Love your articles.  Keep up the good work!!  

 -Stephanie in WA

I frequently get questions of this nature: “I’m nauseous close to when I’m expecting my period, do you think I’m pregnant?” Or “I took a pregnancy test and it’s negative, but I’m having symptoms of pregnancy. Why?” While there is no way I can determine rather or not someone is pregnant based on their symptoms (maybe you just ate some bad Indian food?), I do think questions like this bring up an important issue– a whole lot of us find the hormonal ups and downs of our menstrual cycle to be pretty mysterious. I’m fairly sure the menstrual cycle was covered in high school health class, but I’m also fairly sure it was delivered in a really abstract manner or the teacher just passed a maxi pad around the class. What is usually missing from the menstrual conversation is a decent explanation of how menstrual hormones might make you feel during the different phases of your menstrual cycle.

I am now going to do my very best to dissect the menstrual cycle and its mysterious hormones and give some constructive ideas for dealing with it all. Since I am framing this explanation in the context of a physiological cycle, that is, not influenced by hormonal birth control or disturbed by menstrual irregularities, I am going to use my cycle as an example of how the process works on a hormonal level, as well as how I (and many women) might feel while these processes are carried out. Although I am by no means representative of all women, we need to start somewhere.

The Basics

First, let’s cover some menstrual essentials:

  • The length of your cycle will likely vary. Anywhere between 28-32 days is average for most women, but any variation on either side of that can be normal. It’s important to remember that your body is not a machine and variations are really normal, acceptable, and healthy.
  • The first day of your cycle is the first day you bleed. The moment you begin your period is day number one.
  • The last day of your period is the day before you bleed. Example– my period started on August 25th, making it the first day of my period. My period started again on September 24th, signaling the beginning of a new cycle and the end of my last cycle. The last day of that cycle was September 23rd, making my cycle 30 days long. So, the first day of your last period is the first day of your cycle. 

The menstrual cycle is basically divided into three parts:

  • The Follicular Phase
  • Ovulation
  • The Luteal Phase

There are six hormones your hypothalamus and pituitary gland use to orchestrate these events- gonadotropin-releasing hormone (GnRH), follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone, estrogen, and progesterone. The first four, while important, mostly work to ripen your egg for ovulation. For the sake of keeping things simple we’re going to concentrate on estrogen and progesterone since they have lots of influence on your mood.

Allow me to further elaborate by anthropomorphizing your hormones for a moment-

  • Estrogen– the sex goddess of the hormonal posse, she works in conjunction with serotonin receptors in the brain to make you feel really, really delicious. Careful- she wants you to get pregnant. Immediately. She is partly responsible for ovulation, releasing that one precious, hopeful egg in preparation for fertilization.
  • Progesterone- The hungry bitch of the group. She’s responsible for most of your PMS symptoms, making you bloated, tired, paranoid, anxious and nauseous. Her evil reign of terror reaches its peak about a week before your period begins, signaling the beginning of PMS. Progesterone is most definitely what is causing the “pregnancy symptoms” Stephanie asked about in her question, as it is the hormone that’s produced in high quantities if you become pregnant and can cause stereotypical “pregnancy” symptoms.

(For a great, far more detailed explanation of GnRH, FSH,and LH and the biology of the menstrual cycle, see this post)

Riding my Menstrual Cycle, Week by Week

Using myself* as an example, let’s review the hormonal roller coaster that is the menstrual cycle:

August 25th- August 31st, The Follicular Phase Begins After feeling convinced my period would never, ever come, it finally arrives in the morning, after my estrogen and progesterone level have taken a nose dive, telling my body it’s time to shed that big ol’ bloody baby bed. For about five days proceeding this morning bleed I was tired, pissed off, and my tits felt like heavy, sore bricks. Oh, and I was convinced my boyfriend doesn’t love me anymore. Now that I’ve actually begun to bleed, however, I’m feeling a lot of relief. Sure, I’m crampy, but I’m not feeling close to murdering everyone I see, and I’m pretty sure my boyfriend still loves me. I’m thinking it’s going to be smooth sailing from here on out. I am, of course, wrong.

Dealing with your period– I suggest heating pads, Aleve, lots of toilet paper, and some nice big, stretchy underwear. Oh, and give Cramp Bark a try if you really struggle with cramps.

September 1st- September 8th, The slow climb to ovulation- As the follicular phase continues, I stop bleeding about five days into my cycle. At this point, I’m having what’s called post-menstrual syndrome. My estrogen and progesterone levels have yet to rebound from the chaos of menstruating and I’m feeling irritable, sad, exhausted and disinterested in sex. I’m hormonally depleted, in my dirty pajamas watching Breaking Bad and crying into my bag of Doritos. Even when I have cycles when I’m not really having too much post-menstrual blues, I feel off, not myself. Either way, it’s an odd time for my body and my moods.

Dealing with it Post-Menstrual Syndrome– This can be a really tricky time, since a lot of us don’t expect it. There’s so much attention paid to PMS, but the few days after your period is done can be pretty hard, too. I suggest giving yourself the space to feel weird, add some green tea in there for energy and eat lots of veggies.

TL;DR, A chart for you busy gals out there

August 8th-13th, Scramble my egg, baby I’ve been feeling increasingly better as my estrogen and progesterone levels have begun to climb. My energy is coming back, I’m not too bloated, and my mood is pretty stable. By August 10th, estrogen has climbed to its peak and I ovulate. My skin is soft, the quality of my voice has changed, my hair is shiny and my boyfriend is the sexiest man on earth. I feel totally awesome, loving, excited and my energy seems to have no bounds. I usually get lots of comments on how good I look and how I “glow.” That glow, of course, is the glow of wet panties.

Dealing with it: OvulationEnjoy the ride, girl. I suggest good porn, new batteries for your vibrator, and plenty of condoms. Go ahead and take advantage of the extra energy and get all those extra tasks done, like cleaning the shower.

August 14th-23rd, Luteal Lunacy– As my estrogen levels fall and my progesterone levels rise, I move into the Luteal Phase and start feeling the first twinges of PMS around August 15th. My energy decreases, and I notice I am either ravenously hungry or have a strong aversion to food, sometimes feeling both in the same day (or hour). Around August 17th, as my progesterone levels reach their peak, I begin feeling moody and short tempered and small issues feel insurmountable. There may or may not be lots of tears, an argument with my boyfriend that doesn’t really make sense, and/or a chocolate cake free for all. Physically, my breasts blow up like balloons, my tummy bloats, and I urinate very, very frequently. Occasionally, I will have a few highly energetic, happy days right before my period starts, but that changes monthly. Here’s where Stephanie’s question comes in– pregnancy paranoia can run rampant during this time. You’re experiencing what you perceive to be “pregnancy” symptoms when they are, in fact, symptoms of your period coming. The classic symptoms of pregnancy- nausea and breast tenderness, wouldn’t necessarily be happening yet if you were actually pregnant. Although it’s different for everyone, usually those symptoms come a little later, once the egg has implanted and your body begins to jive hormonally with the embryo, about a week or two after you’ve missed your period.

Dealing with PMS– I suggest keeping a journal and writing down every weird, difficult or unpleasant feeling you have while you deal with this part of your cycle. Know that your feelings may be exaggerated, and use that to your advantage by writing down how you feel. Personally, I find that issues that have been building up for me in my relationships will often come up for me when I’m having PMS, which is pretty valuable information. Instead of exploding at my boyfriend, friends, or my mother, I write down how I feel and make a promise to myself that I will bring these issues up at a better time, when I’m feeling less emotional and ready to not throw things. This has proved to be a very helpful tactic in terms of keeping my relationships strong. Additionally, I will sometimes put out a message to my loved ones if I’m having particularly bad PMS- “Use caution. I’m about to start my period and I hate everything,” or something to that effect. It’s not that my feelings aren’t valid, it’s just that my reactions can be overblown, and I feel my loved ones deserve to know I’m feeling sensitive.

August 24th– Finally. Blood. I feel relieved, hungry and exhausted. Out come the stretchy underwear.

That concludes my not-super-scientific, pretty personal description of menstrual hormones. Let’s keep this going! How do deal with PMS? Does your experience of the various phases of the menstrual cycle differ from mine? Or does it resonate?

As always, please submit your baffling vaginal queries to


*This is an exaggerated synopsis. While I do occasionally have cycles where every phase is difficult and/or very hormone-y, most of the time only one or two phases will be so pronounced. It depends on the cycle, life stuff, or the way the wind is blowing. It will be the same for you, too.


By msvaginascience

Feminist, Mother, Lover, Fat Babe, Student and Case Worker Extraordinaire, serving high risk women and families in Seattle. My background is in Midwifery, Public Health Research, Sexual Education and Childbirth Education.

8 replies on “Ask Ms. Vagina Science- Understanding How Menstrual Hormones Influence the Way You Feel”

thank you for posting this! omg.  this was ridiculously informative.  i experience nearly everything you outlined here, and ngl, i am so relieved.  i thought i was developing some mood disorder or that there was something medically wrong with me because i experience fluctuations throughout the month very very similar to what you outlined.  i actually scheduled an appointment to see a doctor because i was getting really freaked out.

sigh. i can’t believe i was SO ignorant about something so normal.  why didn’t they teach this shit in health class?!

Thanks for the Menstruation Road Map! It has reminded me that maybe the weird moodiness I’m going through at the moment likely has a biological root and not just a quality of life one. When my dude wakes up, I’m going to have him read this. Also, this post reminded me of a book I once owned that mapped out the hormonal changes our bodies go through daily in a 28 day cycle. 28 Days by Gabrielle Lichterman gives women advice on things like when you will be most creative (for writers and artists!) and when you will be most impulsive (for shoppers and weekends in Vegas!) based on the average woman’s hormonal fluctuation. It’s quite scientific and a very enjoyable read. I highly recommend it for a more detailed guide to your period.

This is wonderful.  I pride myself on being well informed about my body, but I had never heard of post menstrual syndrome.  This is the first year I have really noticed it, and I wondered why the hell I was getting PMS after the fact.

My biggest complaint about PMS is that my body is rarely consistent, so sometimes I don’t recognize the signs.  It’s like I have a symptom slot machine with every possible option, including dizzy spells and migraines, and every month my hormones pull the lever for a random selection of three different symptoms.  Frequently when my period starts, I heave a sigh of relief thinking “Oh thank god.  I’m not crazy, I’ve just had PMS.”

I totally have the same issue! Sometimes I will have PMS, sometimes I won’t. Since it’s not always consistent it will take me by surprise and I’ll fly off the handle and feel super vindicated in my ranting, which is…kinda embarrassing sometimes. So, I just assume I’m going to have it and make the necessary preparations.

I think your tip about writing down things that upset you during your PMS phase is a great idea! I’ll definitely have to start that.

A great resource for seeing what phase you’re in is I’ve been using it for a few years and You can use it to track your period dates, make notes on other dates and it’ll even send you reminders Befor eyour period is due. The nerd in me loves the chart of median and standard deviation of cycles and the graph showing what phase I’m in. And it’s free. I highly recommend.

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