I don’t think so, but I never understood female troubles.
No.
No, we can’t. Not without artificial help (something called a menstrual cup). Even if those work for some of us, it is best not to leave it there for more than a few hours.
I’ll put it to you graphically. Menstrual blood is no longer useful blood - it’s more or less “dead” (I lack the medical term). Our bodies are rejecting it by ejecting it. Would you want something that is decaying to remain in your body?
I thought not.
yes they can (for a while) with handstands and other inversions.
You can’t hold it in with your muscles, like you can hold urine, if that’s what you’re asking. You can sort of minimize the flow at times but you can’t stop it.
It is not just blood, there’s dead tissue in there two.
If a woman happens to have a diaphragm around (I mean the birth-control device, not the thing that gives you hiccups), that can hold it in for awhile in the case of an emergency.
Doesn’t this make you glad you’re not a woman?
Yes, as a matter of fact (as long as you asked), for this and myriad reasons.
But I kinda sorta vaguely always knew that.
Only my cold, black heart.
Possibly the most mind boggling question I’ve seen in my ten years here.
C’mon, the blood’s the best part. Hulk Hogan said so in the “No Pain Pussy Fever” phase of Hulkmania.
Menstrual fluid isn’t “dead” (it was never alive to begin with - it’s *part *of a living thing) and it isn’t “decaying” (unless you have a serious infection). It’s also not blood - it’s tissue produced by the endometrium, about half blood and half cells and water.
It is liquifying, though. Hormones turn tissue that’s normally about the consistency of a chicken liver into something more liquid (although chunks of liver-consistency stuff may still remain…hey, you’re not eating lunch while you’re reading this, right?) and causes little cellular “hooks” to detach from the wall of the uterus. At the same time, the opening in the cervix widens a little bit to let it pass out. None of these things are under voluntary control. So no, women can’t hold it in.
Menstrual cups can be left in for hours and hours - they need to be emptied if they’re getting full, but other than that, they can be left in indefinitely during your period. They are much less likely than tampons to cause vaginal irritation or toxic shock syndrome (a staph infection of the vagina) because they don’t absorb moisture from the vaginal walls or cause tearing where staph bacteria can settle in.
So you can collect your menstrual fluid before it exits the body, using a menstrual cup or a tampon, but you can’t stop the flow of menstrual fluid out of the uterus through the cervix.
I think WhyNot has answered this question quite thoroughly, so I am now dying to know and compelled to ask, what the heck brought this question on?
Just idle curiosity, or was there some period related event?
As long as we’re fighting ignorance here…how much warning do you get before it starts coming out?
Do you just start wearing a tampon or pad or whatever when you estimate it might happen?
Depends on the woman.
Some of us get cramps a day, or two, or an hour, or two, before the actual Red Tide rolls in.
Some of us are on a very precise schedule, every 28 days or every 26 days or every 32 days or some other, predictable time period. That can change without warning, and a “regular” woman can become “irregular”, but it’s nice while it lasts.
Some of us get some “spotting” for a half a day or a day or two before the flow gets heavy - a small amount of menstrual fluid that isn’t even enough to stain our panties, but we see it on the toilet tissue when we wipe after urinating.
Some of us get no warning at all, and I don’t know anyone whose body hasn’t betrayed her at least once by acting out of character.
Thanks, ignorance fought!
Conversely, one can “knock it loose”, a task that I, as a male, am not entirely opposed to performing.
Amen!
Someone was asleep at the wheel during sex education class.
*“Fighting ignorance since 1973 (It’s taking longer than we thought!).”
*
I’ve got to say I’ve learned a lot more about how all this shit works on the Dope than in Health class in high school.
I don’t think it’s all that bad a question, honestly. I mean, how would you know, if you don’t have periods yourself? You can “hold it” for pee and poop, so…why would menstruation be different? It’s different because we don’t have voluntary muscle control over our cervix, but we do over some of the sphincters in our bladder and anus.
It would be so totally awesome if we could control our cervix, wouldn’t it? Childbirth would be so much easier! 
(I still don’t understand why repeatedly whacking the scrotum during sex doesn’t hurt, but a gentle tap otherwise causes writhing on the floor pain. There are some things you just need the equipment to fully understand!)
I did say that I did not know the medical term, which is also why I put the word “dead” in quotes. I thought my phrasing would have made that clear. I guess I thought wrong.