Cervix changes position through menstrual cycle. What are the mechanics of this?

[hearthsock.livejournal.com]

That pretty much says it! I understand that the cervix is a contiguous part of the uterus.



So when the cervix sits low in the vagina near menstruation, or high in the vagina around ovulation, what is happening? Does the uterus change position too? Or is the cervix sort of "stretchy"? Can you explain the mechanics of the cervical position?

Any anatomists/biologists who can answer this, I would be very grateful. Thanks!

Comments

[frolicnaked.livejournal.com]

I don't have my copy of Taking Charge of Your Fertility handy right now, but if I remember correctly, it says in there somewhere that the fluctuating levels of estrogen cause the cervix to raise and lower.

If you'd like the exact quotation, just let me know. I'll be happy to find it for you once I'm back near my bookshelf. :)

[hearthsock.livejournal.com]

Sure, thank you. Maybe it will say what is happening in the muscles... since I am more curious about what is physically making it higher or lower.

[frolicnaked.livejournal.com]

It's on p.64 of the revised edition: "In addition, the cervix rises due to the estrogenic effect on the ligaments that hold the uterus in place."

The ligament closest to the cervix is the uterosacral ligament:

(http://photobucket.com)

This is totally extrapolation, but if estrogen is causing that ligament to contract, it seems reasonable that it would cause a noticeable change in cervical position and maybe -- since the uterus is larger than the cervix and above the ligament that's causing the cervix to move -- a less noticeable change in uterine position.

That's just a best guess, though.

[marionravenwood.livejournal.com]

This doesn't really get into "why" but here's what FWHC said:

The position of a woman’s cervix changes over the course of her menstrual cycle. Typically, during and in the first few days after menstruation, the cervix is fairly low and firm like the tip of your nose. When the wet cervical fluid begins to show, the cervix begins to move up, become more soft, wet, and open. During ovulation, the cervix is at its highest and most open. After ovulation, the cervix returns to the firm, low, and closed position. (http://www.fwhc.org/birth-control/fam.htm)

This site (http://www.gardenoffertility.com/reprofemale.shtml) says that high estrogen (e.g., during the follicular phase) softens the cervix, moves it higher in the vaginal canal, and opens the os.

Also, how the cervix varies during the menstrual cycle. (http://www.womenshealthspecialists.org/default.asp?cf=self%20help/cervical%20self%20exam/Menstrual%20Cycle%2029) (It's hard to tell the position of the cervix in these pictures, though.)

[hearthsock.livejournal.com]

Yeah, I spend what you might call a generous amount of time feeling my cervix, so I'm well versed in its habits. Alas, it's still not clear what causes its movements.

[teaweed.livejournal.com]

I recall reading from Woman: An Intimate Geography that progesterone makes tendons and ligaments more stretchy so that the pelvis may better accomodate a pregnancy.

[hearthsock.livejournal.com]

interesting. i wonder if women have sprains more often when they're progesteroney.