The NHS calls the miscarriage risk very small, and most adults are already immune from childhood infection, but you should always tell your midwife or GP about an exposure.
The CDC explains the stakes: infection in pregnancy can spread to the baby, uncommonly causing miscarriage and blood, heart, or liver problems, concentrated in early pregnancy. Blood tests check your immunity, and fresh infections get extra ultrasound monitoring for fetal anemia. Blood disorders and weakened immunity raise the adult stakes too. Prevention is hard because the virus spreads before the rash shows; report the exposure rather than trying to avoid it retroactively.
What to do
Common questions
Is fifth disease dangerous in pregnancy?
The honest answer is usually no, but always tell your midwife. Fifth disease, slapped cheek syndrome, is caused by parvovirus B19, a common childhood virus that most adults already had, and past infection generally means immunity. The NHS puts the risk plainly: if you are pregnant and have been near someone with slapped cheek, tell your midwife or GP, because there is a very small risk of miscarriage or other complications. The CDC adds the mechanism and the same calibration: infection during pregnancy can spread to the baby, this is not common, but it can cause miscarriage and blood, heart, or liver problems in the unborn baby, with the risk concentrated in earlier pregnancy. After you report it: blood tests check whether you are already immune, as most women are, and a fresh infection means extra ultrasounds watching the baby for anemia. The same tell-the-midwife rule applies to people with blood disorders like sickle cell or thalassemia and anyone immunocompromised, who can get severe anemia from this virus. Prevention is only partly possible since the virus spreads before the rash shows, so if you work with young children, mention it at your first midwife appointment.