Four weeks after the final treatment, at approximately 28 weeks gestation, a further visit is made to re-evaluate periodontal status using clinical examination and the Florida probe. This examination provides a quantifiable assessment of the success of treatment. Those women in whom treatment has been unsuccessful are offered a further 3-visit treatment plan and we estimate this will be required in 5-10% of the sample. A further two visits, each of 45 minutes duration is scheduled for 32 and 36 weeks gestation, at which times periodontal supportive care and oral hygiene instruction and motivation are carried out as required. Periodontal parameters at these visits are recorded.