Premature delivery by a boa constrictor

Dear VPI,

I have an albino female boa that just delivered a litter of slugs a month early.  There were some complications just after her post ovulation shed and she lost a lot of weight.   The first slug delivered had a dark brown outer membrane; when I opened it, it had what looked to be a baby that was about ten inches long and I think it was from her previous litter 2 years ago.  I'm guessing it was an old snake fetus, but it visually looked more like a bloated noodle with two dark spots like eyes at one end. Have you heard of anything like that?  And do you think this might have been the problem? 

The rest of the slugs were orange with a lot of red veining, they look to have been fertile.  How far along do you think they were before they died? 

Thanks in advance,  Ed     

Dear Ed,

It sounds like that was a premature delivery. If that is the case then the red-veined ova were technically still alive (red veins=circulating blood) but they wouldn't be viable. That dark egg mass could have been a partly-developed retained ovum from a previous pregnancy. Two years is a long time, but we've had snakes retain them for over a year.

There's no one reason why premature deliveries occur and the exact reason is usually hard to determine. It certainly could have happened because an old dead fetus was still retained in the oviducts. More often it's due to the female being obese. There are probably lots of other possible reasons, including too much heat and rough handling.

Sorry about the bad luck.  DGB