Yes, and this basic public health insurance will cover part of the costs of the treatment. There is the possibility of getting an additional insurance which will also cover extra costs during hospitalisation. It is also possible to get a private insurance.
However, there are organisations which provide you with a gynaecologist free of charge, similar to other essential pregnancy services, such as the birth itself and subsequent hospital stay – all of which are covered by the mandatory health insurance paid by anyone who is employed in Belgium. Even women who aren't covered by insurance will find that their pregnancy costs are covered, courtesy of the Public Social Welfare Centre (Les Centres Publics d'Action Sociale, CPAS, in French http://www.bruxelles.irisnet.be/a-propos-de-la-region/les-centres-publics-daction-sociale-cpas, or Openbaar Centrum voor Maatschappelijk Welzijn, OCMW, in Dutch http://www.ocmw-info-cpas.be/index.php/fiche_FV_nl/le_cpas).