I've had a few bouts of this during my pregnancy as well. When it got the worst and dietary change didn't seem to do anything to help, I used Milk of Magnesia. It's not a fantastic solution, but it is OK to use occasionally during pregnancy (since it is not a stimulant laxative), and it worked for me.
Another idea (and I know this one is at least somewhat controversial, but I'll say it anyway) is a cup of coffee. I make it small but relatively strong - and only one per day - and it *sometimes* does the trick.
Lots of prune juice!!!!!!!!!! It's dosn't taste good, but she will be glad for it!
I had 2 very bad episodes of constipation at the beginning of my pregnancy which forced me to take very strong medications for it. Now I take Microlax almost every day - my OB-gyn approved it, this stuff does not go in the blood.
I eat pears and also if you have Fiber One bars, or something similar those are great. Also, moving helped. Not taking a jog or anything, but just being able to move around and walk a little.
The progesterone makes you constipated and she is probably taking progesterone suppositories which makes is even worse... I felt at one point that I had a kidney stone but it was just realllyyy bad constipation. prunes... lots of water no cheese haha.. good luck! take care of her!
Congratulations on the new pregnancy!! Constipation is something that comes up for most of us during pregnancy, whether it be from IVF or otherwise. You will get lot's of different suggestions, so have your wife try some of the different ideas until she discovers what works best for her. We are all a bit different. For me, a handful of dried apricots worked really well. Also, yogurt and lots of fibre. I ate a lot of whole grain bread, cereals, etc. And make sure she drinks lots of water. Constipation is a pretty common symptom in pregnancy and usually can be handled through diet. It is never a bad idea for her to also mention it to her Dr. He/she may be able to help as well.
It's great you are taking such an active interest in your wife's pregnancy. Congrats again and I wish you both well.