Note: this was originally posted on my blog on tumblr.com. I have tried to convert some of the formatting over, however there may be some inconsistencies. Also this particular entry was written before I knew how to cite scientific sources, so sources will either be nonexistent or incorrectly cited.
It has come to my attention (via citydin and transportive) that no one really knows if a female regenerator like Claire could get pregnant. So if you were wondering this deep and burning question, look no further.
Warning: talk of pregnancy, menstruation, blood, and other things women deal with on a monthly basis.
NOTE: There was considerable debate and discussion on this post. I am not going to repost it all right now, but if someone would like to see it I would be happy to add all the comments at a later date.
This is assuming that Claire Bennet is a biologically normal XX female with functioning reproductive organs as well as normal hormone levels. If she is an XO female then analysis done below may be incorrect.
First let’s answer the easiest question: would a female regenerator’s immune system prevent the woman from carrying the fetus to term? Yes this is the easy question.
In a woman that is not pregnant if a foreign body such as a heart from a heart transplant is placed inside of her, her immune system will go on red alert. Messengers called chemokines tell the white blood cells that the organ transplanted in does not belong, and the white blood cells attack and destroy the cells that make up that organ.
So when a normal woman is pregnant why doesn’t her body react by destroying the fetus? Take note that the explanation that I’m about to give has only been proven in mice, but it is the best answer that science has right now. In a normal person the fetus is surrounded by several sacks. One of these is the decidua, which is also the uterine lining that a woman sheds during her minstrel cycle. When a woman becomes pregnant the decidua surrounds the fetus and prevents the mother’s chemokines from altering the immune system of the fetus’s existence. The mother’s womb becomes a type of immune system dead zone.
In the case of a female regenerator like Claire there is no reason why the decidua wouldn’t work the same way as a biologically normal woman. However Claire’s immune system is much stronger than a normal immune system. Either her decidua would have to be adapted to much more efficient white blood cells or there would be complications like preterm labor, spontaneous abortion, or preeclampsia.
And that’s not the only complication. A normal woman sheds her uterine lining (decidua) about once a month when she menstruates. This prevents the lining of her uterus from getting too thick. If the lining does get too thick, from not having a period for several months, this will eventually lead to a very intense bleed or even cancer.
It seems unlikely that a female regenerator would menstruate. She may drop the egg, however her lining would not shed because her body cannot allow the injury to occur. The wound would heal too quickly. So instead the cells of the uterine lining would build up month after month and become extremely heavy. She cannot have a massive bleed to relieve the stress so this would likely lead to Endometrial cancer because of the unrestrained cell growth. This isn’t normally a problem for the regenerator because her immune system keeps the cancer from spreading outside the uterus. In fact one of the symptoms of Endometrial cancer is a blood-like discharge, so she would probably just think that she is having her period.
But there could be complications if the regenerator were to get pregnant. Some women with Endometrial cancer can have children, but this is not guaranteed and if they are not in remission it is often with the help (via medication for the cancer) from the doctor. It is unlikely a female regenerator would know that she even has cancer, especially if she has manifested to the point where she cannot feel the abdominal pain that the cancer causes. So when the uterine lining envelops the fetus, if the cancer has caused just the right mutations, the decidua may not be able to effectively prevent the immune system from causing a spontaneous abortion
To make the odds of a female regenerator becoming pregnant even lower, their heightened immune system decreases the chance of a sperm ever even fertilizing an egg. In a normal woman, her immune system is activated to destroy the sperm because the sperm are foreign. In some ways this selects for the sperm that can best avoid her immune system. So in a regenerator, her immune system is much more efficient than a biologically normal women, so it is unlikely that any sperm would survive long enough to fertilize an egg.
What are the implications of this? Well it means that there would be very few regenerators. There are only two characters that have regeneration through heredity, and one was born four hundred years before the other. This indicates that it is a very rare ability, likely because of the number of mutations required. And since a woman who is a regenerator is unlikely to pass her genes on, it is only from a male line that this mutation can be inherited.
So if a female regenerator were to become pregnant the following would have to happen: the sperm would have to successfully evade her immune system, her uterine lining would have to have few mutations, and finally the uterine lining would have to be adapted so it was not overrun by her heightened immune system.