First trimester entry into prenatal care is recommended for all women, and especially women with pre-pregnancy conditions. Our objective was to determine whether women with pre-pregnancy conditions were at lower risk of entry after the first trimester (delayed entry) into prenatal care than women without a pre-pregnancy health condition. We used data from 10,890 participants in the National Birth Defects Prevention Study who delivered liveborn infants without birth defects. Women reported pre-pregnancy conditions and timing of entry into prenatal care during a computer-assisted telephone interview. Multivariable logistic regression analyses were conducted to evaluate whether having a pre-pregnancy condition was associated with delayed entry into prenatal care compared to women without pre-pregnancy conditions. Approximately 13% of women reported delayed entry into prenatal care, and 18% of women reported a pre-pregnancy condition. Delayed entry into prenatal care was not associated with pre-pregnancy cardiometabolic or neurologic conditions. Women with thyroid conditions were less likely to report delayed entry into prenatal care (prevalence odds ratio (OR), 95% confidence interval (CI): 0.55 0.32, 0.94), but women with hematologic and respiratory conditions were more likely to report delayed entry into prenatal care (OR: 1.95 1.00, 3.82 and 1.27 0.95, 1.72, respectively), compared to those without any chronic conditions. Future research investigating the success of early prenatal care among women with thyroid conditions could identify ways to reduce delayed prenatal care among women with other pre-pregnancy conditions. •Timing of prenatal care in women with pre-pregnancy health conditions is unknown.•Over 10% of women with a livebirth entered prenatal care after the first trimester.•Timing of prenatal care entry varied by the type of pre-pregnancy health conditions.•Women with thyroid conditions were likely to have first trimester prenatal care.