## 3 Results and Discussion
### Cd Exposure Schemes
#### 3.2.1 Cd Exposure of Dams during Pregnancy Period  
From the 52 records included in this review, seven described Cd exposure of dams only during pregnancy (Figure 2a). All the reports were performed on rats and published from 1981 to 2013. The experimental features, summarized in Table 1, show differences in the administration route, dose or concentration, exposure time and effects determined. The intragastrical route was mostly reported (3/7), compared with intraperitoneal (1/7), intravenous (1/7), drinking water and inhalation chamber (1/7). The Cd-concentrations reported were 50 mg CdCl\({}_{2}\)/L by drinking water and 0.02 mg CdO/m\({}^{3}\) by inhalation chamber, which were the highest and lowest concentrations of Cd exposure during pregnancy, respectively. The highest Cd dose was 20 mg/kg body weight (b.w.) intragastrically and the lowest was 1 mg/kg b.w. intravenously. Cd was administered as a single dose, as several doses in different pregnancy days, or daily during the gestation period. The reports  
Figure 2: Cd exposure schemes. (**a**) Administration of Cd during pregnancy period, from days before mating (DBM) or gestation day zero (GD 0) to the partutition day (PD). (**b**) Cd exposure during lactation period, from PD to the weaning day (WD). (**c**) Scheme of Cd exposure during pregnancy-lactation, from DBM or GD 0 to WD or until offspring reached adulthood (PND n). Purple line represents Cd administration described by most of the authors, whereas gray line indicates Cd exposure mentioned by some authors. of daily Cd administration varied the time of onset and termination of exposure. Most of the authors described dams being allowed to breastfeed their litters and then the Cd effects were evaluated in the offspring. Only [PERSON] et al. (2012) conducted the cross-fostering strategy, whereby the litters of the Cd exposed dams were exchanged with those of the control groups at birth, enabling surrogate parenting (Figure 3). Litter normalization was described by most of the authors (6/7) and the effects on offspring were evaluated before WD, at WD or until adulthood (PND 84, 90, 120 or 180). [PERSON] et al. (2013) included in their work an experimental group of Cd exposure during lactation, while the works of [PERSON] et al. (2014) and [PERSON] et al. (2015) comprised experimental groups exposed to Cd during a pregnancy-lactation scheme. The Cd effects related to these experimental groups are mentioned in Sections 3.2.2 and 3.2.3, respectively. Effects of Cd Exposure during Pregnancy Period  
Cd administration during pregnancy particularly impacts prenatal development. The effects determined in the offspring that were exposed to Cd gestationally included neurological, biochemical, and sexual modifications. [PERSON] et al. (2014), [PERSON] et al. (2015), and [PERSON] (2016) observed neurological effects. [PERSON] et al. described an increased activity of brain enzymes (acetylcholinesterase and Na+, K+-ATPase) in newborns that was ameliorated after Cd-free lactation. [PERSON] et al. and [PERSON] performed behavioral tests and concluded that Cd alters electrophysiological functions at PND 84 and reduces exploratory activity at PND 90, respectively. Although, [PERSON] et al. and [PERSON] reported different administration routes (intragastric and inhalation chamber, respectively) as well as dose/concentration of Cd, both papers described a neurological Cd effect on offspring in adulthood. The dams were administered with Cd by inhalation chamber for 160 days, while dams exposed intragastrically were administered Cd over 10 days. Thus, the exposure time of dams could influence the effect observed in their offspring. On the other hand, [PERSON] et al. (2012) determined renal alkaline phosphatase activity as an indicator of renal damage in cross-fostered groups. Pups fed by their biological mothers exposed to Cd exhibit diminished alkaline phosphatase activity compared to pups exposed to Cd gestationally but fed by unexposed mothers.