Understanding Toxoplasmosis Levels During Pregnancy: What Do My Results Mean?

Question
Last June when i was 5 weeks pregnant i tested for toxoplasmosis:

IgG: 16.2 IU/ml (Normal: 0-3 IU/ml)
IgM: 0.18 index (Normal: Up to 0.5 index)


This April when i became pregnant the second time (m/c the first)toxoplasmosis test results were:

IgG: 9.2 IU/ml
IgM: 0.30 index

As i understand from my doctor, its a problem for the fetus but she could not explain me what these results mean exactly. Can you please explain me these numbers and should i be worried to become pregnant again? If i had it 11 months ago, how come i still have it? Is it a primary infection? Will my baby be at risk?

Answer
Dear Sarah,

Toxoplasmosis is caused by a parasite called Toxoplasma gondii. The parasite is in the intestine of cats and shed in cat feces, mainly into litter boxes and garden soil. You can get the parasite by handling cat litter or soil where there is cat feces. You can also get the parasite from eating undercooked meat from animals infected with the parasite.

Healthy adults usually will not suffer ill effects from toxoplasmosis, though some may have mild flu symptoms when they acquire the infection. However, if you become infected while pregnant, your unborn child may also become infected. Infected babies may not develop any disease, or they may become very ill with serious damage to the brain and eyes. This is why pregnant women are cautioned against being around cats and/or litter boxes and to always wear gloves while gardening. If you have been infected previously (at least 6 to 9 months before your pregnancy) with toxoplasma, you will develop immunity to it. The infection will not be active when you become pregnant, and so there is rarely a risk to your baby.

The IgM is an indicator of recent infection, while the IgG is an indicator if past infection. It appears that your IgM is within normal limits. This would seem to mean to me that your infection was in the past. However, this IgM/IgG thing can be a pretty complicated thing. You really need to talk to your OB doctor in more depth. Tell him/her you understand there can be issues with the baby with ACUTE infection, but your infection was obviously months ago, so doesn't that reduce the baby's risk? (He should be impressed that you've done your homework.) Also ask what, if any treatment or screening tools will be done to monitor for potential problems with the baby.

I hope this has helped you and answered your question. I wish you well.

Brenda