## 4 Discussion
### Folate Transporters SNVs and Pregnancy Failure  
There is not much research on folate transporters and pregnancy failure. [PERSON] at al. [39] examined folate-metabolizing gene variants and pregnancy outcomes in Estonian women undergoing IVF or ICSI. By genotyping single-nucleotide polymorphisms, they found that heterozygosity for FOLR1 1816 C/delC (rs3833748) and 1841 G>A (rs1540087) was associated with a raised risk of pregnancy loss. The rs2071010 variant of the FOLR1 gene, also examined in our work, in the Estonian population showed a non-significant trend towards a lower percentage of previously failed IVF treatments (84.94 \(\pm\) 4.84%) in individuals with the GA genotype compared to individuals with the GG major homozygous \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**SNV**} & \multicolumn{3}{c}{**Genotypes**} & \multicolumn{3}{c}{**Log-Additive Model**} \\ \cline{2-6}  & **0** & **1** & **2** & \(p\) **Crude** & \(p\) **Adj.** \\ \hline \multicolumn{6}{c}{Newborn Weight} \\ \hline rs2071010 & 3477.61 \(\pm\) 385.84 & 3582.86 \(\pm\) 616.03 & — & 0.502 & 0.448 \\ \hline rs630074 & 3435.28 \(\pm\) 363.63 & 3505.41 \(\pm\) 428.86 & 3502.17 \(\pm\)383.76 & 0.477 & 0.599 \\ \hline rs61886492 & 3479.19 \(\pm\) 397.77 & 3540.00 \(\pm\) 445.62 & — & 0.663 & 0.725 \\ \hline rs11545078 & 3495.90 \(\pm\) 408.83 & 3423.00 \(\pm\) 354.57 & — & 0.459 & 0.171 \\ \hline rs3758149 & 3500.85 \(\pm\) 429.77 & 3468.00 \(\pm\) 374.84 & 3460.00 \(\pm\) 371.38 & 0.657 & 0.741 \\ \hline rs1051266 & 3510.61 \(\pm\) 413.02 & 3496.54 \(\pm\) 412.60 & 3439.43 \(\pm\) 375.03 & 0.462 & 0.284 \\ \hline \multicolumn{6}{c}{Placenta weight} \\ \hline rs2071010 & 630.75 \(\pm\) 114.42 & 605.71 \(\pm\) 69.25 & — & 0.569 & 0.612 \\ \hline rs630074 & 612.78 \(\pm\) 118.87 & 638.44 \(\pm\) 112.94 & 630.87 \(\pm\) 100.99 & 0.461 & 0.410 \\ \hline rs1886492 & 631.22 \(\pm\) 114.12 & 605.56 \(\pm\) 87.48 & — & 0.512 & 0.600 \\ \hline rs11545078 & 630.75 \(\pm\) 116.08 & 622.00 \(\pm\) 92.88 & — & 0.752 & 0.883 \\ \hline rs3758149 & 619.07 \(\pm\) 118.09 & 644.00 \(\pm\) 106.95 & 595.00 \(\pm\) 97.52 & 0.585 & 0.638 \\ \hline rs1051266 & 630.91 \(\pm\) 98.50 & 641.83 \(\pm\) 123.88 & 609.14 \(\pm\) 106.23 & 0.415 & 0.382 \\ \hline \hline \end{tabular} Mean \(\pm\) SD, \(p\) adjusted by age, BMI, gestational age and newborn sex.  
\end{table} 
Table 7: Associations between newborns’ weight, placenta weight and genotypes in healthy controls. genotype (94.00 \(\pm\) 1.69%). In our study, a more frequently, non-significant A allele was observed in women with RM compared to controls (0.059 vs. 0.029, \(p\) = 0.115). Much more research has been conducted on SLC19A1 gene polymorphisms. In the above-mentioned work by [PERSON] et al. [39], the rs1051266 variant was associated with a reduced number of previously failed IVF treatments for GA heterozygotes and was more prevalent among fertile controls [39]. In a case-control study (82 RM women and 166 controls) in the Chinese population (Kunshan City), it was observed that combinations of two rare alleles, SLC19A1 80G-SLC19A1 696C (rs1051266 and rs12659), had a lower frequency in RM patients (\(p\) = 0.084) [40]. A study by [PERSON] et al. [41] examined the associations between folate metabolic pathway gene polymorphisms and unexplained pregnancy loss (UPL) using matched maternal and fetal samples. No significant differences were detected in fetal samples between the UPL group and the control group. However, the frequencies of allelic combinations (G-T-A) for variants (RFC-1 80G>A, MTHFR 677C>T, MTHFD1 1958G>A) were significantly higher in the samples of mothers from the UPL group than in the controls (OR = 3.577, \(p\) = 0.049) [41]. Two studies analyzed three polymorphic variants (-43T>C, 80G>A, and 696C>T) of the SLC19A1 gene with recurrent miscarriages. The first one found an association between recurrent miscarriages and the combination of genotypes and haplotypes of these variants in the population of South Korean women [15].