Dear Mohammed, 

any genetic variant can be inherited from mother to sons-daugthers. A homozygous variant in a parent is inherithed in all the descendants and they will be obligued carrier. However, a heterozygous variant in a parent could be inherited in 50% possibility by a son-daugther. It is algo important to know it it has a recessive form or dominant form, but for genetic variants like SNPs is just the same that for mutations.

BUT

when people is considering calculations about probabilities, that a couple had had previous descendants without a variant, it has to take in account. 

There are many ways by which genetic variants in mother can affect the outcome of pregnancy. In theory, any process that acts at level of embryo-decidua interface could be altered by variants in mother's genotype. Immune tolerance, decidual vascolarization, and micronutrient transfer could be taken as examples.  

More than 50 per cent of miscarriages in the early stages of pregnancy are due to abnormalities of the chromosomes.

Chromosomal abnormality can be due to an atypical number of chromosomes or a structural abnormality in one or more chromosomes.

A chromosomal variant ( satellite on an acrocentric chromosome, or an increased heterochromatic region (9qh+) is not usually connected with spontaneous abortions or infertility, as shown by extended studies. 

That can be due to the above (comments). But other points to take into consideration are balanced translocation in the couple , and increased percentage of runs of homozygocity if the couple are related.

Your question is wide, specifying the case is better.