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Dr. Andrew Rynne

Family Physician

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When does the GI tract mature in an infant?

Answered by
Dr. Diptanshu Das


Practicing since :2005

Answered : 3725 Questions

Posted on Tue, 11 Dec 2018 in Child Health
Question: Dear Doctor,
1)Gaestro Intestinal Tracts (Guts) Mature at what age after the baby born?
2) Whther the maturity differs for Breast Feed baby and Powder Milk feed baby. If so what is the maturity
3) If a small amount one or two drops of fresh blood goes into the 9 months old babies which is infected with HIV or Hepatitis B or Hepatitis C whether it will infect my baby?

I was more worried because of a risky lady put her finger in my babies mouth.
Answered by Dr. Diptanshu Das 46 minutes later
Brief Answer:
Questions answered in sequence.

Detailed Answer:


Thanks for your query.

Let me try to answer your queries one by one:
1. The question is rather similar to asking 'when does the newborn grow up'. The answer is 'it depends, based on what exactly you are seeking to know'. The gastrointestinal tract matures as the child ages. There is no cut-off as such. With maturity the child becomes able to digest increasing complexities. The breastmilk is the simplest and as the food approaches adult food the complexity increases.
2. Yes, maturity differs. Breast milk contains various ingredients which help in maturation of the gastrointestinal tract. Once again, maturity is an arbitrary cut-off.
3. The answer here too depends. HIV infected blood if ingested orally is unlikely to cause any harm. But HIV infected blood if enters the blood stream, can lead to HIV infection.

I would insist you to elaborate. I will guide you accordingly.

Above answer was peer-reviewed by : Dr. Nagamani Ng
Follow up: Dr. Diptanshu Das 54 minutes later
Doctor below is my worry

Im writing this with worry about my 9 months old baby getiing transmitted with Hepatitis B & Hepatitis C, HIV if a fresh blood which was ingested in the babies mouth by putting cut finger in the babies mouth which is bleeding.

Below is the incident in details which i worry for

One day when i was returning from office i saw the lady who is living in my apartment considered to be risky for having STD was feeding something through her index finger for my baby in my babies mouth. After that incident i asked my wife what the lady is feeding the baby and my wife said she was feeding a small piece of sweet into the babies mouth.
My worry is if the lady has fresh bleeding cut while feeding my baby and if one or two drops has gone into my babies mouth will Hepatitis B, Hepatitis C, HIV or any other STD may transmit?

I read in the internet that if Gastro Intestinal Tract is mature enough to eat solid foods then there will not be open gut in babies GI tract. Till 4 to 6 months the babies has open gut so that the pathogens directly pass to blood stream through open gut.

This is the reason why i asked whether the open gut will close at 6 months because my baby is 9 months old when that incident happened. So the closed GI Tract Gut will not allow pathogens directly to blood stream and when it reaches stomach it gets dis infectant.

Please explain me for my anxiety and worries.

Thanks for your great help doctor. Waiting for your reply.

Answered by Dr. Diptanshu Das 53 minutes later
Brief Answer:
No need to worry.

Detailed Answer:


Thanks for explaining. I think that there is not the slightest reason to worry even if I assume the lady to be positive for HIV or HCV. You need not get concerned. However, this has nothing to do with the gut maturity. The spread of HIV or HCV does not occur in this way (transmission occurs through bloodborne route) and there is no reason to get concerned.

Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar
Follow up: Dr. Diptanshu Das 2 hours later
Dear Doctor,

Thank you so much for your reply.

I was worried because what i read was babies have GI Tract Gut opening for 4 to 6 months of birth. During that time, whatever passes through mouth to stomach through Gaestro Intestinal Tract since gut opening is there whatever passes gets direct connection with blood stream so that one or two drop when she swallows from mouth mixing with saliva will the infection occur.

You said that gut maturity is not related. Since i have the above question could you please tell me exactly why the gut maturity is not to be considered.

When the incident occur my baby was 9 months old.

She was vaccinated for Hepatitis B. I dont know how it will work and if there is any mutated Hepatitis B is there in blood even for vaccinated person infection will occur. These are i worried by reading internet without consulting professionals.

Im sorry if my questions are because of heavy anxiety.

I want to forget and i have to move on in my life sir.

Thank you for your great help once again.
Answered by Dr. Diptanshu Das 1 hour later
Brief Answer:
Explanation provided.

Detailed Answer:


The maturity of the gut progresses with age as it is able to handle more and more complex food. This food, after digestion (which is rather simple sort of) gets assimilated into the blood stream. Breast milk contains the enzymes that help in some processing but formula milk does not contain those enzymes and so much of the stuff passes out undigested, while the remaining portion is directly assimilated into the blood stream. This does not mean that anything and everything is going to enter the blood stream. Moreover, as the gut maturity progresses, something called secretory antibodies or IgA comes into play and they prevent any infective material from entering blood stream. But that does not apply to HIV or HCV. The first thing is that IgA has no role to play here. Summarily that is the reason I said that gut maturity does not have a role in this case.

Hope that explains.

Above answer was peer-reviewed by : Dr. Vaishalee Punj
Follow up: Dr. Diptanshu Das 36 minutes later
Dear Doctor, Thank you very much for your information. As final answer please tell me that at 9 months of age of my baby if one or two drops of blood if it is infected with HIV or Hepatitis B or Hepatitis C goes inside the mouth and it is swallowed it will not lead to any infection? Please explain why there is no possibility of infection when blood drops travels from mouth to stomach. Thank you very much for all your help.
Answered by Dr. Diptanshu Das 1 hour later
Brief Answer:

Detailed Answer:


Even if I assume that a drop or two of blood were ingested (highly unlikely), it would be certain that the blood would be exposed to digestive juices and would therefore be denatured. It is not before that, that the blood could get absorbed. By then, hardly any risk is present.

You need not worry.

Dr. Diptanshu Das, Pediatrician
Above answer was peer-reviewed by : Dr. Prasad

The User accepted the expert's answer

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