https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3519057/
I've heard of fetuses growing outside the uterus before (generally due to a ruptured ectopic pregnancy), and while in most cases the fertilized egg will just get absorbed back into the body, sometimes that little fucker can survive and it can implant itself anywhere it feels like, including the abdominal wall and even other organs.
In the case of this study, which looks at two separate cases of hepatic pregnancy, the fetus attached itself to the woman's liver. The first case involved surgical removal of the fetus at 18 weeks because in cases of extrauterine pregnancy, it's not considered viable and is treated more like an abnormal growth than a "happy accident." In the second case, the pregnancy was discovered at 18 weeks, but was allowed to continue until 34 weeks because reasons. Both women died from hemorrhaging or complications caused by hemorrhaging in spite of the doctors' best efforts to stop the bleeding after the clumpectomy.
Stuff of fucking nightmares right there. I'm sure a lot of people would say that this kind of a thing is a miracle and "life finds a way," but it sounds like the survival rate of this particular problem is pretty goddamn low. As if ectopic pregnancies weren't bad enough, imagine surviving a ruptured one only to learn that the clump grabbed hold of an actually vital organ instead. Thankfully, this is a pretty damn rare complication of tubal pregnancy (1.4% of all ectopic pregnancies turn into hepatic pregnancies). Unfortunately, since it's a rare complication, it also means doctors may not know exactly how to deal with it and it means you're gonna be more of a guinea pig than a patient if you've got a fetus sucking on your liver.