Oral health behavior and risks during pregnancy and after birth affect the oral health of babies and toddlers. We examined the oral and gingival health and caries prevalence of 150 postpartum women shortly after giving birth and assessed their knowledge of oral hygiene using a questionnaire. We also compared the oral health knowledge of nulliparous and multiparous women. Although most participants (98.0%) understood the importance of maintaining oral hygiene in children, their overall knowledge of oral health was medium–low, regardless of the number of previous pregnancies. Only 4.6% of women received oral health advice from their obstetrician during their pregnancy. Most participants had a high gingival index score, which correlated with dental pain during pregnancy. In contrast, the number of decayed, missing and filled teeth was significantly lower in first-time mothers. There was a statistically significant positive correlation between women who regularly visit their dentist and those who regularly take their children to the dentist. Expecting mothers should be educated about their own oral health and that of their developing fetus and children. Raising awareness among obstetricians with regards to this topic may be an effective way to achieve this.