I gave the following answer to a similar questioned recently asked in the June'09 Pregnancy forum. I believe I started feeling the "ligament" pain around 30 weeks, only because I was breeched before then and there was not so much pressure on my ligaments. 23 weeks sounds early but anything is possible? The pain is getting progressively worse at night when rolling from side to side now (currently 36 weeks), but I have less then 28 days now - yipeee!
Yes I am feeling the same thing. I am 35+3 days and I have been feeling like this for almost a week. I am "waddling" more and the pain is slowly getting "worse". I read that this is normal. It usually starts 2-4 weeks before you go into labor but this can vary up to 6-8 weeks too. It is very comfortable turning over while sleeping and having the feeling that I have to go urinate all the time even after I just have gone to the bathroom :-) Right now I am just happy I am no longer breeched. I am hoping that swimming will help.
"As you get closer to your due date, the cartilage and ligaments that join your pelvic bones increasingly soften and relax, causing an expansion that allows your baby to pass through the birth canal more easily. These changes cause some pregnant women to waddle, says Carolyn Sampselle, a professor of nursing at the University of Michigan. Lightening, when your baby descends lower into your pelvis prior to birth, can also cause the telltale waddle. Some women experience lightening several weeks before their babies arrive. See the website: www.babycenter.com"
My sister-in-law commented that swimming in the pool eased the discomfort. So, she went swimming every time she had a chance.