Objective To investigate inequalities in antenatal care initiation and to assess whether early pregnancy recognition may reduce these inequalities. Design Population-based birth cohort study. Setting Rotterdam, the Netherlands. Population A cohort of N=4196 pregnant women from Generation R. Methods The association of individual and socioeconomic factors and gestational age at pregnancy recognition with timing of antenatal care initiation were assessed using linear regression analyses. G-methods were used to estimate the reduction of the inequalities in antenatal care initiation, if everyone would have recognized the pregnancy within 6 weeks after the first day of menstrual period. Main Outcome Measures Antenatal care initiation was derived from electronic patient files of 10 midwifery practices in Rotterdam. Results Those who recognized their pregnancy within 6 weeks (81.7%) had their first antenatal care visit 1.26 weeks (95%CI:-1.59; -0.93) earlier than those who recognized their pregnancy after 6 weeks. All factors were significantly associated with timing of antenatal care initiation. Modeling a situation in which people would recognize their pregnancy within 6 weeks resulted in a significant reduction in the inequalities in antenatal care initiation for age, migration background, pregnancy intention, education, employment, household income, housing, and neighborhood deprivation. Conclusions Early recognition of pregnancy would reduce the impact of socio-economic inequalities in timely initiation of prenatal care.