Return Home

Fetal Consequences

Monday, April 30, 2012 - 09:00 PM

Mother's day is nigh. Sort of. Anyway, without knowing it, you might have already given your mom a pretty lasting gift. But whether it helps or hurts her, or both, is still an open question. In this Radiolab short, Robert updates us on the science of fetal cells -- one of the first topics he covered as an NPR science correspondent.

Six years ago, wearing his NPR science-correspondent hat, Robert presented listeners with this question: what if we told you that legions of fetal cells hang out inside a mother for decades after she gives birth -- and might even help heal her when she's sick or hurt? Back then he described this as a "too dangerously beautiful idea" for the scientists researching fetal cells. They wanted to believe it, but the evidence wasn't there yet. One of those scientists was Kirby Johnson at Tufts University, who explained that the cells might also hurt the mother. He wasn't sure which. "I think that that's something that we're going to see within the next five years or less," Kirby said. So, Robert thought it was high-time to call Kirby for an update, and to ask once again about Kirby's personal stake in the work he's doing.


More in:

Comments [49]

Heather from California

I just recently stumbled across this episode and it really struck a chord with me. I have had 4 pregnancies and have 3 children (and one unfortunate miscarriage). Prior to pregnancy I was extremely healthy with little to no health issues. With each pregnancy I noticed more health complications. After my third child, I began having health issues that now point to some form of autoimmune disorder, however, doctors cannot place what is going on with my body.

In addition, I had one serious melanoma that was found after my 3rd pregnancy. When the cancerous tissue was analyzed my oncologist told me that the healthy cells surrounding the melanoma had been fighting hard against the cancerous cells and were successfully slowing its growth. Though the research is young, it is interesting to me that the fetal cells in my body could potentially be either helping or hurting me... or maybe both.

May. 03 2017 12:43 PM
Gissell Jazmin Verduzco from Orange County

Really liked the topic, but I wonder why the story was covered mainly by men, knowing this is a topic about women and their bodies.It is great that they presented good information about the topic, but I believe we only heard a little from one woman. Would woman gynecologist have a say in the issue? What about women OB-GYN's? Do they have any information on this?

Mar. 01 2017 01:16 PM
b from Chicago

David K's battering of the guest on whether or not his cells had a positive or negative effect on his mother is ANNOYING. How many ways does the guest have to say that all he cares about is the truth.

Jan. 14 2016 12:37 PM

They key to this is blood type. If the mom is 0- and the dad is positive, the flow of fetal cells back can cause autoimmune issues due to RH factor. Parents with the same blood type are less likely for the mother to develop hashimotos, RA, lupus, etc after having children.

Nov. 13 2015 01:18 PM
John from New York

Dear Mr. Krulwich,
Emotion doesn't dictate facts. I don't understand why you insist the scientist tells you what you want to hear as opposed to the researched findings. I'm sure most of us FEEL better if those cells are beneficial to the mom, but I doubt the cells care, even a little, about our feelings. We are in effect discovering their purpose not defining it.

Jul. 02 2015 03:48 PM
Ayn A Tennyson from oviedo

It is crazy to think that cells of a baby can remain inside a woman even if the baby itself isn't inside the womb anymore. It is a bit hard to wrap my mind around, although very interesting. More research should be done about this, because I would love to know more and I feel there are some empty holes in the topic.

Apr. 13 2015 10:37 PM

This is fascinating and left me with so many questions. Through IVF I carried and successfully birthed a child that is the result of egg extraction from my wife (2 women + 1 sperm donor = baby). I wonder how much of mom #1, mom #2 and the donor's DNA has been transferred back and forth. #mindblowing

Mar. 11 2015 01:53 PM

So this makes me wonder, since I have a child who inherited a chromosomal duplication from his father, are those cells that are still inside me hurting me? Looking at how my husband and son are doing, I think probably.

Dec. 01 2014 01:23 AM
Sarah from St. Louis

I know this podcast was from a while ago, but it was my first time hearing it today. This was incredibly comforting to me to hear. I have lost a couple of babies to miscarriages and knowing that they will always be with me has brought tears of joy. Thank you.

Sep. 16 2014 04:41 PM
Michelle from Omaha NE

This comment is for Kirby-
I have listened to this short about 5 times now, and am always taken by the sincerity in your voice when you discuss the conversations about your work you shared with your mother towards the end of her life. I work in the healthcare industry in a hospital, and I have been near to many families as they spend their last days, hours, moments with loved ones. I hope you find solace and strength while you continue your work by recalling those conversations you shared with your mother. The emotional bond you two shared and the love you showed her through your actions as an adult seem to have made a positive impact through the hardest times of her life despite how good or bad your fetal cells in her body may have been. I wish you the best with your research!

Apr. 13 2014 05:31 PM
Thinker from Arizona

Here's another thought. Lets say a woman has a child and it leaves behind a collection of its cells. Admittedly these contain some foreign DNA from the father. Let's say she has 5 children with the same man. Same DNA contribution from the same father each time. Chance of a conflict triggering an autoimmune response is not increased because the foreign DNA is consistent (and there may even be a natural suppressant) from pregnancy.

Now consider a woman who has 5 children from 5 different fathers. They leave behind 5 different DNA samples. The chance of an autoimmune reaction for each DNA group adds because they are all different, hence one would predict a 5 fold increase in autoimmune reactions sans a pregnancy protection mechanism.

Now consider a woman who has unprotected sex with 5 men but no pregnancy. (See the information in "The You In Me" below.} She gets foreign DNA without a protection mechanism.

The results should be drastically different, and I expect in less than 5 years we'll know, but the minimal risk would seem to favor the woman who has sex with only one partner and bears only his children. Next would be a woman who has children with each lover (assuming a protection mechanism triggered by pregnancy). At the end of the line is the woman who has unprotected sex but no children.


Some years ago it was learned that eating certain foods (chicken cartilage) decreased autoimmune response in joints through a mechanism that protected us from becoming allergic to our food. This could provide another protection mechanism.

Feb. 10 2014 04:20 PM
Leonard Umina from Arizona

Check out this article:

This may be the start of a scientific case against pre-marital sex. If a lovers DNA remains in the woman, and that DNA is not the same as the father of her children, and but gets transferred to her children, the foreign DNA from her lovers can be recognized by their immune systems with an increase in autoimmune system diseases. There are two references in this article - one in the very beginning and then further down as you read it. Autoimmune diseases have tracked the sexual revolution. Could this by why?

Feb. 10 2014 03:34 PM
Premier Visas from London

This is a fantastic article. I will definitely come on that site in future. Premier Visas

Jan. 11 2013 05:43 AM
Virgil from NYC

You are `free thinking` to a extreme, giving feelings or chose where is none. One needs to know their limits.

Oct. 27 2012 10:09 PM
marciemallow from Idaho

I Know I was a little slow getting around to this one, but was playing catch up on my favorite radio show today and just got done listening to this episode. Thank you, thank you, THANK YOU so much for sharing this. The science of all of this is extremely fascinating and more important, to me, was discovering I still carry the fetal cells of the precious little boy I lost earlier this year. I can't begin to express how incredibly happy it made me to hear this. Good or bad, I'm just so glad to know I still have something of him left behind! :*)

Aug. 18 2012 07:22 PM

A Viet shaman once told me "Spirit is the ancestor of Science."  What the soul knows intuitively, science will spend decades studying and trying to "prove".  Now, through science we can take someone's voice, project into outer space to a satellite and back again to earth to a recipient through a cell phone. Shamans have been doing that for thousands of years to the disbelief of Science. Science is not objective, it has an objective rooted in a Western way of knowing (Cartesian logic). There arre many other ways of knowing which Science can only fumble at comprehending as a blind person feeling an elephant's trunk. Scientists can never get to the Truth of a Mother's Love;  a microscope will never reveal the spirit.   This only demonstrates what mothers have always known to be true: All of our children are with us always as we are with them.  We transcend.  Love is.

Jul. 22 2012 12:51 PM
nancy from los gatos california

I really enjoyed this show. A comment at the end made me especially happy, as a mother, to hear that mother's should own the world is marvelous and from what I've seen of mothers, so true!
on a more serious note...
perhaps the presence of fetal cells as a positive influence in the mother happens to keep the mother alive and healthy to look after her children indefinitely, an evolutionary process. also, maybe the fetal cells that are partly the father and now in the mother explain why even after divorce a woman feels like she is not free of the ex, like ever. and maybe the connectedness between fetal cells in mother, child and father explain why men (who have no fetal cells) seem to find it easier to leave the family behind than women or children do. just conjecturing, but we dont know otherwise, so maybe....just maybe.

Jul. 18 2012 06:27 PM
Geena from Denton, Texas

While I think Brian and girlwithglasses bring up excellent points, and it was pretty "innocuous" according to Galen for Robert to lead the story in the way he did... I choose to withhold my criticsm in the face of these facts:
- this is a story originating from Krulwich Wonders, a VERY editorial series, so take it with a grain of salt
- I believe that Robert's honesty, albeit somewhat crass and unprofessional in the realm of journalism, acts as a foil to the scientist, who wraps up his soundbite with a scientifically satisfactory statement: that he is searching for the truth, no matter how brutal or "too dangerously beautiful" it can be

So although Robert may rub us in the wrong way here, it may have been on purpose, because he is not meant to be the hero of the story -- nor is Kirby. I think the real hero of this story, as its been framed in the short write-up here, is the impact this information can have on women who have had and/or lost children, which is coincidentally the demographic majority of those who have commented in a positive manner. And as Holly Copeland points out, that no women were interviewed is THE most glaring way in which this story was remiss.

Jun. 26 2012 05:40 PM
P Moore from Kentucky

I would like to raise another possible usage for the fetal cells found in mothers. Could these fetal "stem" cells be harvested and used if the child developed a condition which required stem cells for treatment? Perhaps this is the sole reason for their existence and the questions of this being a good/bad thing for the mother is irrelevant? As a mother, I would feel privileged if I could provide the means for giving my child life a second time.

Jun. 17 2012 03:57 PM
Ana from Ohio

Thank you for a wonderful and fascinating story. I didn't think that the researcher was actually considering the fetal cells to be "good babies" or "bad babies" with intent to harm or help. As a parent it is hard not to feel responsible for less than optimal traits out children inherit, so as a child I can see his concern for what role his fetal cells played in his mother's health.

I'm a new listener and look forward to listening to many more episodes. Thank you.

Jun. 05 2012 11:09 AM
susannah from south africa

I gave birth to 7 babies and had 7 miscarriages in between.
I am 52 years old and in perfect health, I mean perfect health.
Who knows?

May. 29 2012 05:30 AM

This was an especially fascinating interview for me to hear as I struggle with a newly-diagnosed autoimmune disease, 5 years after becoming a mom. I have always felt the two were connected; the theory that those fetal cells may have "caused" my predicament stopped my breath for a moment, but my breath returned when I heard they actually may be helping instead. In either case, the research is exciting and I do wonder what else we might learn from it. Thank you!

May. 23 2012 11:01 PM

Loved this episode ! As always- radiolab is great

May. 22 2012 01:32 PM
Zenqi from Morro Bay, CA

I love Radiolab, but I didn't get anything from this short. I'm left wondering why anyone would make a career out of answering the questions raised here unless the cells could be harvested for treatments of disease.

So much of science, at the end of the day, do nothing to make us happier in our lives. This seems to fall under that heading.

May. 16 2012 05:41 PM
Ben from Westchester

I have to echo the other comments here -- these are cells. They are not sentient. They don't want to "help their mommy" or "hurt their mommy" or "kiss their mommy" or whatever. They do whatever they are molecularly programmed to do.

RadioLab is a show that typically takes its science seriously. It was really annoying to hear you wading into this sewer of anthropomorphizing everything. It's like that brain dead phrase "happy as a clam." How happy is a clam? Do you really think that a bivalve has much emotion?

You guys need to take a break.

May. 16 2012 01:50 AM
2dogmom from wisconsin

I have to echo the comments of Brian and girlwithglasses, I was really disappointed in the ascribing some "motive" to the fetal cells and saying that somehow we should feel guilty or take credit for what these cells do. Maybe the cells are there because the placenta is leaky and cells leak through and it has not been selected against because it does not affect the evolutionary fitness of the mothers. Only things that would affect evolutionary fitness will be selected for or selected against. There can be "slop" in the system as long as it does not have an effect on fitness (mostly measured by the survival of our offspring and there reproductive success).
I usually LOVE Radiolab but was really disappointed by Robert's wanting to attach a "meaning" to these cells being there. I think the interesting thing about the cells being there is that all mothers are chimeras--we carry cells from our babies along with are own.....really makes you think about our ideas of self.

May. 14 2012 03:08 PM

I agree with Brian. The whole presentation of the story in terms of foetal cells in the mother doing 'good' or 'bad' was both misleading--presenting it as if the cells have some conscious agency of their own or were controlled by the offspring somehow--and an unnecessary oversimplification: most members of the audience can surely comprehend that these cells have multiple effects, and not all of these have been elucidated.

The addition of the 'human interest angle', framing Kirby Johnson's research as some sort of catharsis for his mother's death, was standard Radiolab procedure, but hearing Krulwich clutching at straws at the end of the podcast, trying to get some big emotional ending to the story--"scientist finds out foetal cells are good and can finally get over mother's death!" or "scientist finds out foetal cells are evil and blames himself for mother's death!"--was maddening. Science is a tool for gaining knowledge about the world, and although scientists may have different motivations for going into certain research areas, the aim is to know more. Science isn't for working through emotional issues: that is what therapy is for. Suggesting that any scientist might give up his research because he wasn't getting emotionally satisfying results ("So as the story gets blurrier and blurrier, why are you still in the game?") is extremely insulting to anyone who works in science. It was also a pretty crass and insensitive thing to ask someone.

I enjoy Radiolab for the most part, but the insistence on making everything into a story--particularly when scientific content doesn't really fit or is not entirely substantiated--greatly weakens the program's appeal.

May. 12 2012 07:11 PM

I enjoy your show, and I know it's just prior to Mother's Day, and that this researcher had a personal stake in his research. But I do think that posing the same, personal and emotional question to a researcher about his research multiple times (how do you feel about how you may have helped or hurt your mother?) was neither entertaining nor very professional.

Science is all about having no fear before the uncomfortable truth, and I am sure your interviewee understands this.

May. 12 2012 04:42 PM

I had a miscarriage about 5 years ago and have since had two babies. While I've always counted my first as a pregnancy, I have never really considered myself a mother of three until now. It is a beautiful thought that our baby is still with me in a way. Thank you.

May. 11 2012 12:25 AM

I just want to tell you how profoundly this piece moved me. I was pregnant once, in my 20's, but lost the pregnancy in the 6th month. I never managed to have another child. Knowing that some of the cells of that baby are still alive in me? That's the most comforting thing I have ever heard.

May. 10 2012 09:38 PM

This was so fascinating! I loved this short (especially being a mother). Though it could have been longer. I wanted to know even more about this research and its complexities!

One point, though, on the idea that fetal cells helping mothers -- except in the case of auto-immune diseases. There was a study from 2010 that showed women with Multiple Sclerosis (an auto-immune disease) who have children actually have a better long-term prognosis than those who don't. ( Whether or not this has anything to do with fetal cells is to be determined. If so, this may be an example of how fetal cells help mothers with auto-immune diseases.

Thanks for a great show!

May. 10 2012 12:40 PM
feathered_head from Washington

If there is a hypothesis that the father's genes can cause different physiological reactions in the mother, it makes me wonder if the effect could be amplified when a donor eggs are used and the fetus is completely unrelated to the host. Are there any studies documenting the incidence of autoimmune disease or cancers on women who have used donor eggs or have been a surrogate? Women's health is already put at great risk from the hormones they are given during infertility treatments, but if the foreign fetus itself could be also a danger to her...?

May. 07 2012 10:45 AM

The 'help' v. 'harm' debate is somewhat interesting philosophically, but I think neither Robert nor Kirby Johnson mentioned the obvious scientific point of view: like in any study, no mater whether you consider it 'help' or 'harm', if you understand how it works, you can ultimately use it to help. Anything we understand better, brings us closer to useful discoveries.

May. 06 2012 09:56 PM

This episode, despite its lack of conclusive scientific evidence of the role of fetal cells in the mother's body, nevertheless made me catch my breath. The loss of my son made it so difficult to breathe. For two years I saw the world without color - only in shades of gray.I marveled to think that some bit of him is within me still! I'll hold that thought tight for a bit. Thank you Radiolab.

May. 06 2012 05:17 AM


There is a book called something like The Autobiography of a Species in 21(or 23) Chapters that might give you a different perspective.

May. 05 2012 08:15 AM

Wow...Beans, really? I have to admit, being a right-wing nut job, sorry, cohort, I actually had to look up the meaning of the word "elide" (def: "omit", "slur over"). I realize that this is equivalent to Daniel striding into the lion's den (dang, Biblical reference) about Carl Sagan striding into a NASCAR party...but, was it really necessary for you to point out that cells and fetuses aren't human? This story had absolutely nothing to do with that. Are you really that insecure?

Being a pro-lifer, and an an NPR listener, I am always astounded at how terrified/defensive people are of even alluding to the fact that there are other intelligent people out there who disagree with the "accepted" (read, Legal) stance on personhood.

The last time I checked the law, you can still legally destroy a fetus (person), but not a "fully grown human being".

May. 04 2012 02:51 PM
Galen from New York

Robert says something in this story which is innocuous in this context, but reveals a serious problem that often leads to inaccurate journalism, especially in areas where the journalist is not an expert:

"It would be a much better story. . . for me. . . if it had gone clearly one way or the other, but the story you're now telling me is that you and your brother can now meet for coffee and you can now look into each others' eyes and you will not know between the two of you whether you helped your mom, whether you hurt your mom, whether you did both, whether your contribution was bigger or less than the hapstance(?) of your dad's genetic makeup, and and and and and and . . . This is getting to be a much harder story to tell. . . So as the story gets blurrier and blurrier, why are you still in the game?"

Now, Robert is a first-rate journalist, and he embraces the increasing complexity and ambiguity of the story, but he was noticeably irritated that the story wasn't conforming to his idea of what makes a good story. In fact, one of the things Radiolab is consistently good at is identifying questions with no simple answer and narratives that don't have a clean, satisfying trajectory, and making the fact that it's unsatisfying part of the story. But most radio shows and newspaper articles aren't Radiolab. The desire to tell a "good" story--a story that's easy to tell, emotionally satisfying, with a beginning middle and end--leads journalists to shoehorn the facts into a narrative they're comfortable with. It probably also leads them to focus on covering stories that are easy to tell and to ignore stories that are harder to tell, even if those stories might be more important.

I don't mean to criticize Robert--on the contrary, foregrounding the problem of the unsatisfying narrative is a smart way to handle the difficulty. And it's hard to criticize other journalists for making the mistake. Humans seem to have a strong cognitive bias for simple stories, with clear good guys and bad guys, right answers and wrong answers, beginnings and ends. Journalists aren't exempt from those biases, AND they have an economic incentive to cater to the biases of their audience. I'm tempted to talk about good journalists versus bad journalists. I wish I had a simple, elegant solution to the problem. But it's not that simple.

May. 04 2012 12:10 PM
Dave from Preble, NY

Great show! I wonder if "fetal cell protection" has anything to do with why women, on average, live longer than men.

May. 04 2012 06:48 AM

Dear radiolab,

I think you're swell, in general, though I do have an issue with this week's short. Throughout, it seemed like both Robert K. and the scientist elided the definition of person and fetus. Even if the scientist's fetal cells had been running around supporting the mother, in no imaginable understanding of *agency* would the scientist have been in any way responsible for the behavior of any of the fetal cells that share his DNA. Implying otherwise was irresponsible in an era when a majority of the leading right-wing cohort believes that a group of fetal cells has more rights than a fully grown human being.

May. 03 2012 10:59 PM

this makes the whole mothers have a deeper connecting with their children and the whole mothers can sense when something is wrong so much more meaningful! simply amazing.

May. 03 2012 07:06 PM
litamia from Tennessee

Melissa addresses another issue. Do our relationships with our children determine if their cells are good to us or bad? And do the number of their cells within us determine when we can "cut the strings" or not?

May. 03 2012 10:19 AM
litamia from Tennessee

Could the difference be RH factor? My husband has positive and I have negative and I have an autoimmune disease?! After four births and two miscarriages, at times the bad fetal cells win?... hmmm...

May. 03 2012 10:13 AM
Holly Copeland from Lander, Wyoming

Thank you for this fascinating podcast. As a mother, however, there was an aspect to this that you didn't really explore, which is the emotional connection of having those fetal cells within us. Even if my children's cells don't directly fight disease (though it sounds like they do), knowing that they live within me is a tremendous emotional comfort. It would be so intersting to hear from other women to see if they feel the same way. Sorry guys -- but it really seems as though women should be interviewed in a topic that so involves them. And, what about women who have lost a child? I have a close friend who lost a baby at 3 weeks and I imagine (i'm planning to ask her), that knowing those baby's cells might live in her heart cells. That's HUGE! Well, such a fantastic story all around. Thanks, as always, for your reporting...

May. 03 2012 09:08 AM

Amazing story! I'm surprised that I didn't already know about the leakage of fetal cells even though that news was at least 6 years old!

Obviously the science is still uncertain, but I think the findings up to this point are still poetic despite being complex. The relationship between fetal cells and mother mirrors the relationship between children and mother. Children can be a blessing, but they also require self-sacrifice from the mother. Her body is so affected by the children from beginning to end! Also, the average mother would probably view the possibility of harm from fetal cells as another necessary sacrifice.

I wonder if fetal cells could also be involved in the mother-child bond.

May. 02 2012 09:36 PM
Pete from melbourne Australia

The comment that 'everywhere there is trouble there is fetal cells, therefore we think they are helping', seems a leap to far to me. the notion could just as easily be that fetal cells are everywhere there is trouble because they caused the trouble.

I didnt hear anything that sounded like a clear causal link.

Also mice are not people, biologically speaking they are not all that similar, they are cheaper and easier to experement on than people, but what happens to them wont always happen to us.

Its an interesting topic, but it seems like after five years they would be doing better research.

May. 02 2012 07:59 PM

I went to In the Dark in Salt Lake and it was awesome!

May. 02 2012 03:12 PM
cesaer the end, you said nothing

May. 02 2012 01:15 PM

Thank you for doing a first broadcast on the science behind pregnancy/ motherhood - so far the only one tagged with those words! - hoping for more on this :-)

May. 02 2012 04:32 AM

Yes but who said that your fetal cells are You? And that as a consequence you should be held responsible for the role these cells are playing in your mother's organism.

May. 01 2012 03:50 PM

Leave a Comment

Email addresses are required but never displayed.

Supported by