Is it permissible to wean a one-year-old child due to a four-month pregnancy, given the husband's strong opposition to it?

The default is for the mother to breastfeed her child for two full years, which is preferable and more complete. However, it is permissible for her to wean the child before that, and it may be recommended or even obligatory if breastfeeding causes harm to the child or the mother. As for the medical perspective, that is for doctors to determine. The spouses are advised to engage in calm dialogue, consider the interests of both parties, and seek assistance from Allah.