When I was pregnant with my second child, this is what happened to me. I was in the middle of the "feel good" sonogram at 21 weeks when the technician made a funny face and said that she was having difficulty getting some measurements.  Her supervisor came in and took over, after asking me whether I had any other children and whether they were normal.  And then I spoke with the radiologist, who was blunt and dour, and helped me get an immediate referral to Children's Hospital, where, several specialized sonograms later, we got as grim a verdict as I could possibly have imagined:  a severe brain defect, a severe heart defect, other highly unusual but not easily interpreted "signs" of impairment, including structural or neurological deficits associated with swallowing and other motor functions.  It all pointed to chromosomal anomaly, but, too bad for me, it wasn't possible to get definitive diagnosis in the time frame I had to make up my mind to obtain a legal termination.

My choices were to do nothing, undergo termination with less than definitive diagnosis, or wait for the definitive diagnosis, and then go to New York or Colorado, or, I guess, Kansas.