moms, babies and blood

[orphanedhawk]

One of the many things I don't understand about hepatitis C is since it is in our blood, why then don't those of us who are mothers, pass it on to our babies?
They share our blood during pregnancy so logically it seems to me, they'd be born with the disease as are AIDS babies.

I'm fairly sure I caught HCV before my daughter was born yet she and my son both tested negative.
Could they have a natural immunity because of my carrying it?
What do you think?  

[Marcia2202]

We do not share blood with our babies during pregnancy. That's why mothers and children can have different blood type and rhesus factor.

During child birth, sometime some tiny amounts of blood is exchanged into eachother's blood stream and Hep C can be transmitted.

Children do not have natural immunity to hep c, because we carry it. About 6% of children born to hep C positive mothers become infected. Ca 8% girls and 4% boys.

[Isobella]

It can also pass from mother to child when breast feeding.  Sometimes mom's nipples crack and bleed and the baby is exposed thru their teething gums.  

It can also depend on the viral load of the mother when she gives birth.....the lower the load, the less the chance of transmission, as explained to me by my hepa.

[orphanedhawk]

Thanks for the replies. I admit to my ignorance! And I did wonder about blood types.

However, I did read an interesting thing about viruses and how one generation gets very sick from for example, the flu epedemic in 1918 and how the next generation had antibodies to that particular flu.
This is what lead my thinking that perhaps our kids could have a natural immunity.

[lalapple]

like mentioned above, what i was told:  the exposure is risky during childbirth.  although it is rare, there is a 4-6% chance of transmission.  i know a hcv treatment researcher, he's been studying hcv monitoring patients for 18 years and told me that he hasn't seen one case of positive transmission.  

[Isobella]

Sounds like I need to meet him, lol!  

I agree that the odds are low....unless you are one of the 6%.  In my family we hit it 1 for 1.  100%.  :(

[newleaf09]

I read that the higher the mother's VL, the more likely transmission.  My son, born 4 years after I was infected, has hep c (and does not think he was exposed in any other way) but my daughter, born 9 years after my infection, does not.  It's uncommon from mother to child, in any case.

I have trouble believing the breast feeding transmission theory I have read.  Bleeding nipples would mean virussed blood in baby's stomache.  Baby's digestion would destroy anything.  Baby's wouldn't have mouth sores.  How would the infected milk make contact with the baby's blood?  Just doesn't make logical sense to me.

[Isobella]

Bleeding nipples would mean blood in the babies mouth before it gets to their stomach.

The way my doc explained it was that if they were teething when you had cracked/bleeding nipples there was a chance of transmission that way.  Not through infected milk but through infected blood.  

Granted the chance of transmission is probably pretty darn low, but if you think about it...that's why gingivitis and other infections of the mouth can be so dangerous because the gums are a pathway to the blood stream.

Below is what the CDC has to say:

http://www.cdc.gov/BREASTFEEDING/disease/hepatitis.htm

Hepatitis C Virus Infection
Is it safe for a mother infected with hepatitis C virus (HCV) to breastfeed her infant?
Yes. There is no documented evidence that breastfeeding spreads HCV. Therefore, having HCV-infection is not a contraindication to breastfeed. HCV is transmitted by infected blood, not by human breast milk. There are no current data to suggest that HCV is transmitted by human breast milk.

Is it safe for the HCV-positive mother to breastfeed if her nipples are cracked and bleeding?
Data are insufficient to say yes or no. However, HCV is spread by infected blood. Therefore, if the HCV-positive mother's nipples and/or surrounding areola are cracked and bleeding, she should stop nursing temporarily. Instead, she should consider expressing and discarding her breast milk until her nipples are healed. Once her breasts are no longer cracked or bleeding, the HCV-positive mother may fully resume breastfeeding.

[alagirl]

The transmission of hcv in utero is actually about 5% - 15% (higher in mothers believed to have developed hcv as a result of blood transfusion or IV drug use, higher in mothers co-infected with HIV, lower in mothers with no known risk factors at the time of their own infection).  I think one could very well have one child infected in utero and another child, or other children, not infected.  

Earlier studies (early 90's) seemed to suggest that in utero transmission may only rarely occur, and these studies hypothesized that breastfeeding was a big risk factor.  Later studies, however, do find that there is in utero transmission and they are still studying the breastfeeding issues, but transmission rates from breastfeeding are thought to probably be low (2% or less if I remember correctly).  There is some evidence to suggest that higher maternal viral loads cause greater risk of transmission in utero:

Article 1 -
http://journals.prous.com/journals/servlet/xmlxsl/pk_journals.xml_summary_pr?p_JournalId=4&p_RefId=668600&p_IsPs=N

"The risk of mother-to-child, or vertical, transmission of HCV is about 5% overall but can be as high as 15%, depending on maternal HIV infection status and HCV RNA viral load."
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Of the total population of infants and young children who are hcv rna positive, many (from 1/3 to 1/2) are suspected of having been infected in utero.  Type of childbirth (natural vs. elective c-section) was, interestingly, not a factor in transmission rate (according to the following study), suggesting that these infants are more likely infected in utero and not during the trauma of childbirth:

Article 2 -
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1721862

"Conclusions: These results suggest that at least one third and up to a half of infected children acquired infection in utero. Although postpartum transmission cannot be excluded, these data suggest that it is rare. The role of HCV genotypes in the timing and mechanism of infection should be explored further."
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But interestingly, there is a twin study with four pairs of twins, each with only one twin infected.  This study seems to suggest the possibility that in those cases, childbirth IS the mechanism for infection in the second twin:

Article 3 -
http://linkinghub.elsevier.com/retrieve/pii/S1386653206004264

"Summary and conclusions
Transmission of HCV is more likely to affect the second twin, perhaps because placental separation during the delivery of the second twin exposes the infant to infection. Until effective interventions such as vaccination of newborns or antiviral treatment of mothers are evaluated, elective caesarean section could be recommended for HCV twin pregnancies in order to avoid premature membrane rupture and infection of the second twin."
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Another really interesting study showed higher in utero transmission when the mother reported the risk factors of prior blood transfusion or IV drug use than when the mother did not have these (or any other known) risk factors.  Don't know quite what to make of that one - not sure why that would be the case, but it's an interesting result.  The same study showed that hcv antibody positive but RNA negative mothers do not transmit the virus (which was not a surprise to anyone probably, but nice that they studied it):

Article 4 -
http://www.bmj.com/cgi/content/abstract/317/7156/437

"Conclusions: This study suggests that in women not infected with HIV only those with hepatitis C virus RNA are at risk of infecting their babies. Transmission does seem to occur in utero, and the rate of transmission is higher in women who have had blood transfusions or used intravenous drugs than in women with no known risk factor for infection."
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It seems that the safe thing to say is that in utero transmission is between 5 - 15 percent, and that rate appears to be affected by other factors.  It's fairly apparent that more research needs to be done on issues surrounding not only pregnancy, and transmission (to include breastfeeding), but also on the effects of pregnancy on the virus - i.e. whether pregnancy causes any greater risk of viral damage to an hcv rna positive mother.

[alagirl]

One thing I found interesting, is the suggestion that the role of genotype be studied further in regard to in utero transmission.  That would be interesting.  The studies on this topic are fairly geographically disparate - so there may be a much larger percentage of geno 4's in a study conducted in one country vs. geno 1's in a study conducted in the U.S.  *IF* genotype  does affect the ability of the virus to transmit in utero, or the timing or mechanism of transmission, then study results in one country might not mirror results in another.

All of that made me wonder, in general, if the results of studies conducted on adults who are hcv rna positive can really be generalized across genotypes.  Obviously, I already knew that genotypes are different in their response to treatment, but I hadn't really considered whether or not, according to genotype, there might be differences in the rate and ability of the virus to transmit, or in the amount and mechanism of viral damage.

[orphanedhawk]

Thanks for the above~very interesting.
There is so much unknown about these alien invaders in our blood stream!

[Marcia2202]

Article 3....


Funny... This is exactly the opposite to what happened to my twins. It was my first twin who was infected and my second twin not.

[newleaf09]

wow! Excellent, thorough researching of a topic.  Thanks very much.  Lots of food for thought.

[alagirl]

There were only 4 sets of twins in the twin study, and in one set the first twin was the one infected.  So... it wasn't a very big sample group.  It just struck me that sometimes women's and children's health issues are not studied as extensively.  I would love to see more research on this.