## 4 Discussion  
The present study examined clinical endpoints after the perinatal exposure of rats to a 900 MHz signal at the general public and occupational regelmentary thresholds (ICNIRP, respectively, 0.08 and 0.4 W/kg). Here, the male rats showed lower body weight from PND 6 to PND 43 (\(-\)15%) in the OcM group. The female pups showed an earlier start of ear detachment and eye opening in both the exposed groups. Only males showed earlier ear detachment in the OcM group and earlier eye opening in the PuM group. According to our exposure system setup, and to some models in the literature, we presented an estimate of the exposure of the litters from conception until withdrawal. In our estimate based on previous publication [23], offspring absorbed less energy than their mothers from the 2 nd PND (\(-\)55 to \(-\)60%) until PND 14, while they absorbed more energy than their mother from PND 14 until PND 17 (+30 to +40%). The current results showed no deleterious effect of perinatal exposure to 900 MHz signal radiation on gestation delivery outcomes (size of litters, sex ratio, or number of stillbirths) and on the weight and length of the pups at birth. These findings agree with the results we found in a previous study at a similar level of wbSAR (0.07 W/kg) but at the 5G frequency of 3.5 GHz [23]. Interestingly, in the OcM-exposed group, a significant decrease in body mass was observed in males from PND 6 until PND 43. Our results are in accordance with those of [PERSON] et al. [29], who reported that prenatal 2450 MHz exposure at 0.1 W/kg wbSAR in mothers resulted in a reduction (\(-\)30%) of rat growth after birth. GSM exposed fetus rats at low SAR (0.048 W/kg) starting from GD 0 showed impacts on pre- and postnatal development including a decrease in body mass at GD 20 ([30]. Reduction in weight effect of RF-EMF exposure on male pups has also been shown by previous studies. Male pups, when paternal mice were exposed for 10 weeks to a 2000 MHz signal prior to mating and mothers during the gestation period, exhibited significantly lower weight during the adolescence period (4-12 weeks). This study also found a disturbance in glucose metabolism [31]. On the opposite, higher weight gain (+10%) was shown in juvenile male rats exposed for 5 weeks (PND 8 to PND 43), 23 hours per day, at 900 MHz at 0.03 W/kg SAR [13]. Similar results in other studies indicate that prenatal exposure at equivalent wbSAR (0.1 to 0.4 W/kg) but at different frequencies (900 MHz, 2000 MHz, or 2450 MHz) induces decreased weight in male pups. However, exposure at the later stages of development showed higher weight gain in juvenile male rats. Recently, [PERSON] et al. [24] showed that the exposure of adult male mice to 900 MHz at 0.4 W/kg or 0.1 W/kg induced changes in the transcription of genes involved in metabolism and thermoregulation in males. Differences in glucose metabolism between male and female rats have been observed previously [32]. Also, female rats showed a delay in weight gain and less metabolic complications than males when exposed to a high-fat diet [33]. The body length of male pups was lower but not significantly with the permutation test for the OcM (\(p\)-value = 0.0557) and PuM (\(p\)-value = 0.0557) groups. Also, the daily food intake of the litters was sporadically decreased at GD 9, increased at GD 17, and decreased at PND 15 for the PuM group and decreased at PND 6 for the OcM group. Food intake follow-up (grams per hour) showed an increase when juvenile rats were housed in a room at an ambient temperature of 31 \({}^{\circ}\)C and exposed for 5 weeks to 900 MHz RF-EMF at 1 V/m [34]. This increased food intake could be the result of compensatory behavior stimulated by higher energy expenditure after RF-EMF exposure. Our study is the first to show an effect of 900 MHz on precocious development. Data indicated earlier eye opening and pinna ear separation in males, respectively, at OcM or PuM and female pups at both wbSAR after pre- and postnatal exposure. The incisor eruption occurred earlier only in the PuM male group.