Understanding Premature Birth: Risk Factors and Potential Causes

Question
Hi, I know someone who had a premature baby at 26 weeks.  The baby weighed 1 pound 13 ounces.  The preganacy was going fine until about the 23rd to 24th week.  The mother then started to have vaginal bleeding (not spotting).  Around this time she had gone outside and brushed some snow off a car with a broom.  She went to the hospital and they said that she had a urinary infection.  They gave her Macrobid (which she didn't take because she was afraid that it might hurt the baby). They also did an internal, didn't see anything wrong, and then sent her to a specialist.  The specialist discovered that her fluid was low.  She went to the Specialist twice a week to see if the fluid was changing (it only got worse).  They then put her in the hospital for a few days and gave her intravenous which that though might help.  At this time they have her antibotics...geromycin (spelling is probably incorrect).  The fluid was still low and they sent her home which was a mistake.  They gave her Macrobid again and this time she took it.  She did do a little shopping in a store or 2 which seemed to make her bleed even more the next day.  About a week later she went to another specialist and he put her back in the hospital.  They hooked her up to a contraction monitor and it didn't show anything.  The next night she complained that the baby felt like it was hanging low and then they dicovered she was dilated 7 cm.  The did an emergency C section.  The doctor said that the membranes were very weak and possibly were leaking.  They tested the placenta and discovered that the fluid was infected.  The baby is now 1 year old and is doing pretty good.  He has a problem with his thyroid and he has a feeding tube since he doesn't always feed as he should.  Do you think that this could have been prevented by taking the Macrobid the first time? Could the snow brushing have "pulled something" which caused the leak in the first place?   Could the shopping have aggrevated things?  Do you have any ideas of what could have happened?  Thanks for your time.

Answer
Many times these things are never explained and never repeat themselves.
The snow DID NOT cause this I can almost guarantee you.  That is a mild activity.   
The not taking antibiotics may have made things worse as could of the shopping.
Chances are though it was just the way things were meant to be for some reason we may never know.