Q: What is the risk of recurrence of trisomy 9?
A: Trisomy is a condition where you hae 3 (instead of 2) chromosomes. There are generally 23 pairs of chromosomes, each is numbered from 1 to 22 with the 23rd pair being the "sex chromosomes XX or XY.
Most miscarriages in the first trimester are associated with chromosome anomalies, and trisomy 9
(three No. 9 chromosomes) is among the most frequent anomaly found in
miscarriages (about 7-8% of miscarriages), and only trisomy 16 (about
16% of miscarriages) is more frequent.
Trisomy 9 and trisomy 16 are usually not compatible with a normal fetus, and they often abort early on in the first months before the fetus develops.
This is contrary to trisomy 21, for example, which is Down syndrome, and which can develop into a fetus and go to term.
Having a msicarriage with a trisomy 9 is usually a coincidence and has nothing to do with what's going on with the mother or father.
Chances of having another trisomy 9 pregnancy again in another pregnancy are more likely than not by chance, the same as if it never happened before.