## 3 Results and Discussion
### Experimental Features  
Since each reviewed article aimed to study a particular Cd effect on offspring, it was expected that experimental conditions would be different from each other. Even when analyzing administration routes and effects evaluated for each exposure scheme separately, experimental differences were identified (Figure S1). Figure 4 describes the percentage of papers reporting each Cd exposure scheme, the proportion of works evaluating each effect, and the frequency of articles mentioning each administration route. In general, from  
\begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline
**Strain (_n_)** & & & & \\
**Dose/Concentration, Admin Route Exposure Period** & **Collection Time Organ Analyzed** & **Results** & **Year Author** \\
**Liter (_n_), Lactation Days** & & & \\ \hline Sprague-Dawley rats (—) & & & 2004 \\
5 mg CdCl\({}_{2}\), i.g. & & & [PERSON] et al. \\
30 DBM to PND 21 (\(n=8\)), 21 & & & [PERSON] et al. \\ \hline \end{tabular}
\end{table}
Table 3: _Cont._52 records included in this review the most reported Cd exposure scheme was pregnancy-lactation (67.27%), while neurotoxicity was the most evaluated effect (36.54%). Although, Cd in drinking water does not ensure that all dams consume the same dose of metal, it was the most reported administration route independently of the effect evaluated (Figure 4c). Some authors estimated the dose administered in drinking water by measuring the water consumption for each dam. This facilitates to know the approximate dose to compare with other experiments in which another route or dose were used. On the other hand, strategies such as cross-fostering was underreported with only three papers mentioning this strategy. It is important note that differences in experimental features difficult compare and discuss the effects observed. However, the Cd-doses and their effects resumed in Tables 1-3, show that even at lowest Cd dose adverse effects are generated. The experimental features described for each author are ordered in this review allowing other researchers to select the ideal conditions and exposure-scheme for studying the effects of perinatal Cd exposure.  
**Supplementary Materials:** The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/app122211412/s1](https://www.mdpi.com/article/10.3390/app122211412/s1)]([https://www.mdpi.com/article/10.3390/app122211412/s1](https://www.mdpi.com/article/10.3390/app122211412/s1)), Figure S1: Administration route, Cd-exposure scheme, and effects evaluated. Graphs represent the frequency of papers reporting each administration route during pregnancy, lactation, or pregnancy-lactation scheme, as well as the effect evaluated. D.w., drinking water; i.g., intragastrical; i.p., intraperitoneal; i.v., intravenous; f.i., food intake; i.c., inhalation chamber.  
**Author Contributions:** Investigation, methodology, formal analysis, data curation, and original draft preparation, X.A.-P. and J.B.-B.; validation, visualization, and writing review and editing, A.L.-L.; visualization, supervision, writing review and editing, and project administration, J.A.F.d.I.T. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research received no external funding.  
Figure 4: Cd exposure scheme, effects evaluated and administration routes. (**a**) Percentage of works reporting pregnancy, lactation, or pregnancy-lactation exposure. (**b**) Percentage of reports evaluating different Cd effects. (**c**) Number of reports that described each Cd administration route. D.w., drinking water; i.g., intragastrical; i.p., intraperitoneal; i.v., intravenous; f.i., food intake; i.c., inhalation chamber.  
Data Availability Statement: Not applicable.  
**Acknowledgments:** Postdoctoral fellow [PERSON], appreciates the scholarship awarded by the Consejo Nacional de Ciencia y Tecnologia (CONACYT) and the support of Universidad Autonoma de Zacatecas (UAZ).  
**Conflicts of Interest:** The authors declare no conflict of interest.