Infectious diseases to guard against

We call any disease caused by a virus or bacteria an infectious disease （感染病, kansenbyou）. These can move from person to person, but also from pets, livestock and other animals, as well as food and drinks. If you catch an infection while pregnant, it may have an effect on the fetus, so sick people should stay away from pregnant women. Keep good hygiene, and always wash your hands after going out. If a disease has a vaccine, then make sure all the people around you are up-to-date on their vaccinations. （There are some vaccines that cannot be administered to pregnant women）
This is a list of infectious diseases to worry about while in Japan, which may differ from your country.

Rubella （風しん, fuushin）

If you become infected with rubella for the first time during weeks 4 through 20, the baby may suffer deafness, cataracts, glaucoma, or heart disease （CRS - congenital rubella infection）. If you don’t remember ever getting rubella, and you are not immune, you must be careful （you can get tested by your doctor）. Furthermore, there are many men in their 20s and 30s without immunity to rubella. Make sure your partner is up-to-date on his immunizations. However, not all rubella infections will cause CRS. The risk depends on what stage of pregnancy you are in. If you have concerns, please consult with your doctor.

HTLV-1, human T-cell leukemia virus type 1 （ヒトT細胞白血病ウイルス1型, hito ti saibou hakketsubyou uirusu 1 gata）

This virus infects the T-cells in the blood. Most people with this virus will live their whole lives without symptoms but in some rare cases （around 1 person per 1,000 infections） it is possible to develop adult T-cell leukemia （ATL）. Even rare than ATL is HTLV-1 Associated Myelopathy （HAM）, which affects the nervous system. If the mother is a carrier of the virus they may be at risk of transferring the virus to the baby through breastfeeding. It is possible to lower this risk through different breastfeeding methods, which can be determined through consultation with a doctor.

Chicken pox （水ぼうそう, mizu bousou）

An infection during pregnancy can cause eye defects and skin atrophy. The risk will depend on the stage of pregnancy.

Parvovirus B19 （パルボB19ウィルス, parubo B19 uirusu）

This virus brings fifth disease, a skin disease that causes rashes. If you catch this while pregnant, 30% of the time it will transfer through the placenta to the baby, where it can cause miscarriages and fetal hydrops.

Genital herpes （性器ヘルペス, seiki herupesu）

This is a sexually transmitted disease caused by the herpes virus. Blisters and irritation arise externally, and after the initial infection the virus lies dormant in your nerve system, which could cause a flare up during pregnancy. It can infect the baby through the birth canal and cause pneumonia and encephalitis, so a C-section may be needed.

Cytomegalovirus （サイトメガロ ウイルス, saito megaro uirusu）

This is also a member of the herpes family and can remain dormant in your nervous system. Most people gain immunity to the virus with time, but infection during pregnancy can cause liver problems and deafness in the baby.

Chlamydia infection （性器クラミジア 感染症, seiki kuramijia kansenshou）

This is a common STD, caused by chlamydia trachomatis. This infection does not have any outward signs, but it can cause neonatal pneumonia and conjunctivitis in your baby if left untreated. Cure the disease before birth with antibiotics.

Group B Streptococcus （GBS） （B群溶血性連鎖球菌, B-gun youketsusei rensa kyuukin）

Group B Streptococcus is a bacteria often found within the vagina and near the anus. It can cause meningitis and blood poisoning if transmitted to the baby during birth. To prevent this, antibiotics are given to the mother through an IV drip during labor and water breaking. （It does not affect the mother, so there is no need to treat it during pregnancy）

Toxoplasma （トキソプラズマ, tokisopurazuma）

This parasite exists in unprepared meat, cat droppings, and soil. It is a rare infection but it can have an effect on the fetus. You don’t need to worry if you are immune, but try to be as hygienic as possible when disposing of pet droppings.