Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
| Foetal fraction (FF) | Possible conditions |
| Decreased | Increasing maternal age and basal metabolic rate, twin pregnancies (especially with dichorionic twins), Trisomy-13, Trisomy-18 and triploidy, assisted reproductive techniques. |
| Increased | Gestational age, Trisomy-21 |
