The average gestational age of infants was 32 weeks (range, 26.3 - 37 weeks) with a mean birth weight of 1875 g (range, 682-3005 g). (jamanetwork.com)
The exact ages of the infants of the study aren't mentioned in the summary of the report and the report doesn't appear to have been published in a peer - reviewed journal so my access to the specifics are limited. (candokiddo.com)
The mean age of infants at both the first and second postnatal weight measurements did not differ significantly between the groups (6.2 ± 4.7 weeks in the fluoxetine group and 6.1 ± 2.4 weeks in the no medication group at the first measurement; P = 1.0; 15.0 ± 8.0 weeks in the fluoxetine group and 13.9 ± 5.9 weeks in the no medication group at the second measurement; P =.69). (pediatrics.aappublications.org)