TABLE 1.
Demographics of the study cohort (n = 109).
| Variable | Value |
|---|---|
| Maternal Age, yr | |
| Mean | 36.1 |
| Median | 37 |
| Range | 25–47 |
| Gestational Age, wk | |
| Mean | 11.9 |
| Median | 11.1 |
| Range | 10–22.1 |
| Basis of Gestational Age, n (%) | |
| Based on LMP | 9 (8.3%) |
| Based on USS | 100 (91.7%) |
| Type of Pregnancy, n (%) | |
| Singleton a | 107 (98.2%) |
| Twins | 2 (1.8%) |
| Referral Indications, n (%) | |
| Abnormal Ultrasound | 3 (2.8) |
| Maternal Age b | 64 (58.7) |
| Family History c | 2 (1.8) |
| Patient Preference d | 35 (32.1) |
| Multiple Indications e | 5 (4.6) |
LMP, last menstrual period; USS, ultrasound scan.
Includes four cases of demised twin which occurred prior to the cfDNA screening blood draw.
Thirty-eight of these cases had no known indication on the test requisition form (TRF). As the maternal age was over 35 years, we reassigned them as Maternal Age.
For one case, family history details listed sensory motor neuropathy with or without agenesis of the corpus callosum. For the second case, there was a previous affected child/pregnancy (the child is being investigated for Prader-Willi syndrome and other genetic syndromes).
Twenty-four of these cases had no indication listed on the TRF. As the maternal age was less than 35 years, we reassigned them as Patient Preference cases. For the remaining 16 cases, the TRF listed the referral indication as Other, with primary screening test as the detail provided. We reassigned these cases as Patient Preference cases as well.
Two of these cases were originally entered as advanced maternal age on the TRF. As one of the cases also had an NT of 4.6 mm following ultrasound, and the other case had a previous affected child/pregnancy we reassigned both cases as Multiple Indications. The other three cases were listed as Other on the TFF. As one patient had a maternal age over 35 years of age and had a previous failed cfDNA screen at a different provider, we reassigned this case as a Multiple Indications case. The other two patients had a positive conventional screening result and advanced maternal age.