June 5, 2015

Why Are Chromosomes Important?

Why are chromosomes important for a successful pregnancy?

Pregnancy is an exciting time but the anxiety of a having a baby with an abnormal number of chromosomes can be overwhelming. Fear of miscarriage is also a common concern. Difficulty becoming pregnant occurs in 15% of couples trying to have a baby and miscarriages occur in up to 15% of all pregnancies.  A major reason for reproductive difficulty is having either an embryo or a pregnancy with an incorrect number of chromosomes.

Why are chromosomes important? Chromosomes are located in the nucleus of each cell containing the DNA comprising genes. Genes are passed from parent to child making each of us unique. In other words, chromosomes make you, you. Having the correct number of chromosomes is critically important to having a successful pregnancy. If your embryo does not have the correct number of chromosomes then your baby may fail to develop properly. For example, people with Down syndrome have three copies of chromosome 21 (Trisomy 21) instead of the two copies found in other people.

People have 23 pairs of chromosomes for a total of 46 chromosomes. Males and Females differ in a pair of chromosomes called sex chromosomes. Females have two X chromosomes in their cells and males have one X and one Y chromosome.  Inheriting too many or not enough sex chromosomes can lead to serious problems. For example, females who have extra copies of the X chromosomes are usually taller than average and have mental retardation.  Males with more than one X chromosome have Klinefelter syndrome which is a condition characterized by tall stature and often infertility.  Another syndrome caused by imbalance in the number of sex chromosomes is Turner syndrome. Women with Turner syndrome have only one X chromosome. They are usually very short, do not undergo puberty and some have kidney and heart problems.

Preimplantation genetic screening (PGS) of a cell biopsied from an embryo can improve the chance of a successful pregnancy by determining which embryo has the correct number of chromosomes enabling the transfer of that embryo instead of an embryo that does not have the correct number of chromosomes and would be thus less likely to make a healthy baby.  This technology is especially applicable to couples with infertility who have an otherwise poor prognosis for success due to advanced maternal age since the older a woman is the more likely she is to have an embryo with an incorrect number of chromosomes. This technology is also applicable to those with repeated implantation failure where good quality embryos have been transferred but a successful pregnancy did not occur and in women with recurrent miscarriages since most miscarriages are caused by an incorrect number of chromosomes.

If you have questions, or would like to know about our new program IVF Assist Plus, designed with a money-back guarantee to give you a baby with the correct number of chromosomes for the highest chance of a successful pregnancy, please contact us!

Tags: , , , ,
Joseph A. Hill, III, M.D.

Joseph A. Hill, III, M.D. Board-Certified in Reproductive Endocrinology and Infertility