Purpose: To evaluate maternal and perinatal outcomes following modified open fetal or postnatal surgery to repair myelomeningocele at a pioneering referral center for prenatal surgery in northeastern Brazil. Methods: This observational, retrospective cohort study assessed data recorded at the Instituto de Medicina Integral Prof. Fernando Figueira between December 2014 and May 2020. Pregnant women with fetuses diagnosed with myelomeningocele were enrolled. Exclusion criteria consisted of cases for which medical records were unavailable and those for which intrauterine repair was not recommended. Student’s t-test, Welch’s t-test, the chi-square test and Fisher’s exact test were used, as appropriate, in the statistical analysis. Significance level was 5%. Risk ratios (RR) and their 95% confidence intervals (95%CI) were calculated. Results: Of the 134 pregnant women identified in the database, 45 were included: 26 women underwent fetal surgery and 19 infants were operated after birth. Pregnancy complications were more common in the fetal surgery group, including premature rupture of membranes (RR: 14.0; 95%CI: 0.8-263.5; p=0.027) and other complications (RR: 5.3; 95%CI: 1.2-22.8; p=0.025). Fetal surgery was significantly longer than postnatal surgery (mean duration 226 x 71 minutes, respectively; p<0.001). Prematurity was more common with fetal (79.2%) compared to postnatal surgery (13.3%) (RR: 5.9; 95%CI: 1.4-25.5; p=0.017). Although ventriculoperitoneal shunts were more common in the postnatal (18.2%) compared to the prenatal group (0%), the two groups were statistically similar (p=0.50). Conclusion: Prenatal myelomeningocele repair was associated with more cases of adverse pregnancy outcomes and prematurity. Conversely, no cases of open fetal surgery required ventriculoperitoneal shunting.