In plain words
Aneuploidy means a cell has the wrong number of chromosomes, with one too many or one too few. A typical human cell has 46 chromosomes. Aneuploidy is the most common cause of . It becomes more common as eggs age, especially after about 35. Many aneuploid pregnancies end in early loss. Some, such as those with trisomy 21, can be born and may be identified by prenatal screening or testing. Aneuploidy is not caused by something a parent did before or during pregnancy. Clinicians discuss it when testing or a loss raises the question. A genetic counselor can explain what a result means for you.
The deeper version
Aneuploidy arises mostly from meiotic nondisjunction in oocytes, and the frequency of aneuploid embryos rises steeply with maternal age. Age acts chiefly on the oocyte: the primordial follicle pool declines from fetal life, and meiotic errors rise after about 35. Embryo aneuploidy rates climb steeply across the thirties and forties (Franasiak and colleagues, 2014, Fertility and Sterility). Most early miscarriages are sporadic aneuploidies with no increased recurrence beyond the maternal-age baseline. The controversy concerns whether preimplantation genetic testing for aneuploidy improves live birth rates, where randomized evidence is mixed.
Where it comes up
- Trying to conceive: how long is normal, when to ask for helpBefore Pregnancy
- MiscarriageLoss and Complications
- Pregnancy at 35 and olderPregnancy: Your Body
What mothers here say about aneuploidy
No one has posted under this term yet.
Sources
- Franasiak JM and colleagues, Fertility and Sterility — The nature of aneuploidy with increasing age of the female partner (2014)
- American Society for Reproductive Medicine — Evaluation and treatment of recurrent pregnancy loss, committee opinion (2012)