Introduction: In general, everyone believe they should grow as “in utero” for the smallest premature babies but many thinks that it is not possible with today's nutrition “guidelines”. There is resistance to give enough nutrition for fear of "toxicity". We use volumes that some would consider high, although there are more and more groups that accept it. We chose the difference in Z-score between birth and a corrected discharge gestational age to assess postnatal growth in our unit.Material and methods: Between January 2018 and December 2020, we review all cases ≤ 29 weeks of GA at birth that survived to 36 weeks corrected gestational age, or that were discharged home if this occurred before. We had a protocol with extremely aggressive nutrition including parenteral as well as oral nutrition. We then separated the patients who had lost more than 1 Z-score point to see the weight trajectory plotted on the Fenton 2013 growth curve and to review the clinical characteristics of those patients. We also graphed the patients who had had a smaller Z-score difference to also see their trajectory in the Fenton curves. We calculate the number of cases, medians, and interquartile ranges for all groups.Results: We fount 32 cases. The median ± IQR (interquartile range) of change in Z-score between birth and discharge of the whole group was -0.52 ± 0.53; 6/32 (19%) had more than 1 point drop; all had severe diseases listed in Figure 1 with plotting all cases. The median decline in Z score ± IQR of this group with poor growth was 1.24 ± 0.22. The group of cases with a fall of <1 point of Z score were 26 (81%), the median ± IQR of fall of Z score was 0.39 ± 0.55 (see figure 2). All cases had the initial fall in weight the first 1-2 weeks. No important complications secondary to the ingested volumes or parenteral nutrition were reported. Conclusion: The group of cases with a fall of > 1 point of Z score had severe pathologies. The other cases had an adequate growth parallel to normal growth charts in some cases with some catch up.Discussion: With this work we try to show that in many premature babies it is possible to grow like in utero if they are given enough nutrition. Randomized studies are necessary to confirm our findings.