I'm 18+3 and have been constipated on and off for weeks. Every couple of days I have awful pains and discomfort with the urge to 'go' but I just can't!! Then things seem better for a day or so, then the merry hell of constipation returns! It's so bad and is back today. I've been to doctors and spoken to my midwife about it. Doc says I can take lactulose, mw told me to avoid taking anything as it'll make my bowel lazy and make the problem worse. 
I know it's a common symptom of pregnancy so please tell me how you found some 'relief'!! Did you take anything for it?
Help!!