Can parasite, microbes be passed from mother to fetus through the placenta ?

I know some like HIV can be.

  • 1
    $\begingroup$ HIV rarely crosses the placenta and almost exclusively where it has been left untreated leading to vary high viral load - a greater risk is in delivery itself leading to many HIV+ve mothers chose to undergo elective Caesarean sections $\endgroup$
    – Rory M
    Oct 16, 2013 at 22:39

2 Answers 2


Pregnant mothers can indeed pass on various microbes to their fetuses but it is not always directly through the placenta, as the placenta can be protective. Although the blood of the mother and fetus do not mix directly, the two can interact. Maternal proteins can flow across to the fetus, as maternal antibodies are actually the source of a newborn's immune system for a few months, and maternal immune cells have even been found in fetuses, which of course means other cells or viruses can get across.

HIV is a good example for your question, actually. HIV can infect newborns through the placenta, but the majority of infections occur during birth, not in utero. Birth is a pretty bloody process, and the rupturing of the amniotic sac exposes the infant to anything in the mother's blood, which is when most infections occur. For HIV specifically, physicians can all but prevent mother-to-infant transmission by administering anti-HIV drugs just before birth.

Here is a list from the CDC of some STDs which details how infections may be passed on to newborns; most clarify that it mainly happens during the birthing process. That being said, plenty of diseases will cause transplacental infections. Usually they are viruses, as viruses are simply smaller, but there are definitely bacterial and parasitic examples, such as Borrelia duttonii, Trypanosoma cruzi, and Toxoplasma gondii. Here's a list of bacterial ones and here's a list of viral ones.


Parasite are organisms, and they can pass through mother to her child while its in hers womb. Toxoplasma gondii is an example, it passed from mother to child as it moves through her body, and since child is present inside her, of course it will get into the child.

You can diagnose for the parasites, or can even get them treated well just like getting your self treated, but measurements should be taken while treating as the their might be a danger of miscarriage.

So the answer is Yes, parasites can pass through the body of mother to her baby. Since the baby is inside her being a part of her body.

There is an infection called toxoplasmosis which doesnot passed from person to person, yet it can pass while in pregnancy.

Chagas disease is a disease that can get transferred from Mother to her child, during pregnancy. Which is called by a Parasite called Trypanosoma cruzi.






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