Toxoplasmosis in Pregnancy — What to Know and Avoid

Toxoplasmosis is a globally widespread infection caused by the microscopic parasite Toxoplasma gondii. Its lifecycle is complex: the definitive host is the cat, which sheds the parasite in its faeces — but through oocysts and tissue cysts, virtually all warm-blooded animals (pigs, cattle, sheep, birds, and finally humans) get infected. According to the Robert Koch Institute, around 50 % of adults in Germany have been infected at some point and are lifelong immune. A pregnant woman passes that immunity on to her baby.

In healthy adults, toxoplasmosis is usually symptomless — occasionally a flu-like episode, mild fever, fatigue, swollen neck lymph nodes. Dangerous only in two contexts: severely immunocompromised patients, and — the focus of this guide — a first-time infection during pregnancy. When infection is new and you are pregnant, the parasite can cross the placenta. Consequences range from mild later eye problems to severe brain damage or miscarriage/stillbirth. Sounds scary — but the rate of congenital toxoplasmosis in Germany is only 2–7 per 1,000 pregnancies. With the right measures you can push your risk close to zero.

A widespread myth: ‘If I have a cat I must give it away.’ Completely false. A house cat on dry or wet food without outdoor access is almost never a source. Even outdoor cats only shed oocysts briefly during their own first infection — usually as kittens. The most common source of infection is not cats but raw or undercooked meat. EFSA 2022: 70 % of European toxoplasma infections come from meat, only a small share from cat faeces. Good news: keep your cat. Let someone else clean the litter tray, or use gloves if you must.

Why raw meat? In the muscles of infected animals — especially sheep, pork, game, less often beef — toxoplasma is present as tissue cysts. These survive refrigeration but are killed by: core temperature ≥70 °C, freezing at -20 °C for at least three days, and pasteurisation. Germany’s BfR (2021) is clear: pregnant women should completely avoid raw and undercooked meat. That includes rare roast beef, mettbrötchen, and air-dried ham on pizza — air-drying alone is not reliable. Salami is borderline: industrial German salamis after 4–6 weeks of ageing are mostly safe, but not always. When in doubt, skip it.

Cats need a precise look. Cats only shed oocysts after their own first infection — and only for 1–3 weeks in their life. House cats on commercial food rarely get infected. Outdoor cats hunting mice do. Oocysts need 24–48 hours at room temperature to become infectious — the key point. Clean the litter tray daily (ideally your partner does), wear disposable gloves and pour boiling water. You do not need to get rid of the cat. Oocysts do not spread via fur.

Freezing is an underrated trick. Meat held at -20 °C for at least three days has its cysts reliably killed by cold. So salami frozen for weeks and then baked is much safer than fresh salami. But household fridges at 4–7 °C are not enough — it must be the freezer at -18 to -20 °C for three full days. Air-dried hams (Parma 12+ months, Serrano 18+ months) are probably safe per 2023 BfR data, but the BfR still recommends pregnant women avoid them.

Washing fruit and veg: rinsing is not enough. Use clear running water, ideally a brush for firm peels. Soak leafy salad and herbs for 1–2 min, then rinse and dry. Vinegar or commercial vegetable wash provide no extra benefit vs clear water per EFSA. The risk is in the soil on the produce, not the produce itself.

In Germany toxoplasmosis testing in routine antenatal care — unlike in France or Austria — is not covered by statutory insurance. It is only reimbursed on concrete suspicion. As a self-pay the test usually costs 15–25 euros. The DGGG S3 guideline (2023) recommends: once at the start of pregnancy (ideally before week 12), and for non-immune women a repeat in the third trimester. The test detects two antibody classes: IgG (long-term immunity after prior infection, lifelong) and IgM (acute infection, appears after infection, fades over months).

Important: a single positive IgM does NOT mean acute infection. IgM can circulate for up to two years and false positives are common. If IgM is positive, your gynaecologist will order an avidity test — measuring how firmly IgG binds. High avidity (≥30 %) = old infection (>3–4 months), baby safe. Low avidity (<30 %) = recent infection, further work-up. Use an experienced lab — these distinctions are delicate.

If acute toxoplasmosis is confirmed in pregnancy, act fast. First measure: start spiramycin (Rovamycine) immediately. This macrolide antibiotic concentrates in the placenta and prevents transmission. Studies (SYROCOT 2007, EMSCOT 2022) show that spiramycin started within 4 weeks of maternal infection reduces transmission by up to 50 %. Spiramycin is extremely safe for the fetus — barely crosses the placenta, used for decades. Typical dose: 3 x 3 million IU daily, until birth or fetal infection is ruled out.

Alongside spiramycin you get: repeat ultrasound every 2–4 weeks, looking for fetal findings like brain calcifications, hydrocephalus or growth restriction; if suspected, amniocentesis with PCR for toxoplasma DNA (not before week 18). PCR-confirmed fetal infection changes therapy: pyrimethamine + sulfadiazine + folinic acid — a triple combination targeting the parasite in the fetus directly. More side effects (bone marrow suppression) but the evidence-based standard for confirmed fetal infection.

Paradoxical: the earlier infection occurs, the LESS likely transmission — but the MORE severe if it happens. 1st trimester (to week 12): 10–15 % transmission, usually severe (miscarriage, hydrocephalus). 2nd trimester (13–26): 25–40 % transmission, moderate damage, often correctable with therapy. 3rd trimester (from week 27): 60–70 % transmission, usually mild or asymptomatic at birth, but later eye problems (chorioretinitis) can still appear in childhood or teen years.

Alongside toxoplasmosis, listeriosis belongs on the pregnancy map. Listeria monocytogenes can be in raw meat, raw dairy, smoked salmon, deli sausage and pre-cut salads. Unlike toxoplasma, listeria multiplies at fridge temperatures. Pasteurisation and proper cooking kill it. Pregnancy danger foods: raw-milk soft cheese, deli meats, deli salads with mayo, cold-smoked salmon, raw meat, raw sprouts. Fridge hygiene: separate meat and cheese, regular cleaning, leftovers ≤2 days. Most toxoplasmosis measures also cover listeria.

Two closing words: toxoplasmosis in pregnancy is rare — in Germany about 7–20 babies/year have confirmed congenital toxoplasmosis (out of ~790,000 births). Almost all infected mothers who get prompt spiramycin deliver healthy babies. If you skip raw meat, wash produce, wear gloves in the garden and let someone else clean the litter tray, your already-low risk drops to near zero. Paranoia does not help — good habits do. And if something happens, the healthcare systems in Germany, Austria, Switzerland, France, Italy and Spain are prepared for exactly this scenario.