In the 28th week of gestation, the administration of the Anti-D vaccine is recommended for women with a negative Rh factor. This vaccine is intended to prevent Rh incompatibility between mother and foetus.
When there is contact between maternal and foetal blood during early pregnancy, the mother's immune response develops. This results in the production of antibodies against the Rh factor, leading to sensitisation. If the woman becomes pregnant again, these antibodies could attack the foetus and cause a miscarriage. The Anti-D vaccine helps to prevent this sensitisation and its possible consequences in future pregnancies.