Table 1.
Demographic Characteristics, Phenotypic Features, and Pregnancy Outcomes.*
| Characteristic | Value (N = 127) |
|---|---|
| Median maternal age (IQR) — yr | 32 (29–35) |
| Nulliparous — no. (%) | 57 (45) |
| Use of assisted reproductive technology — no. (%)† | 12 (9) |
| Median gestational age at diagnosis of NIHF (IQR) — wk | 20.0 (13.4–24.6) |
| Previous pregnancy with NIHF — no. (%) | 10 (8) |
| Biologic parents consanguineous — no. (%) | 4 (3) |
| Prenatal phenotype at enrollment — no. (%)‡ | |
| Increased nuchal translucency or cystic hygroma | 29 (23) |
| Isolated increased nuchal translucency or cystic hygroma | 15 (12) |
| Concurrent structural anomaly | 9 (7) |
| >1 additional abnormal fluid collection | 5 (4) |
| Single abnormal fetal fluid collection | 21 (17) |
| Isolated single abnormal fetal fluid collection | 4 (3) |
| Concurrent structural anomaly | 17 (13) |
| ≥2 abnormal fetal fluid collections | 77 (61) |
| Isolated abnormal fetal fluid collections | 39 (31) |
| Concurrent structural anomaly | 38 (30) |
| Fetal sex — no. (%) | |
| Female | 65 (51) |
| Male | 62 (49) |
| Maternal race or ethnic group — no. (%)§ | |
| White | 74 (58) |
| Asian | 19 (15) |
| Multiracial | 18 (14) |
| Hispanic or Latino | 12 (9) |
| Black | 3 (2) |
| Unknown | 1 (1) |
| Region of United States — no. (%) | |
| West | 86 (68) |
| Midwest | 13 (10) |
| South | 8 (6) |
| Northeast | 20 (16) |
| Pregnancy outcome — no. (%) | |
| Ongoing pregnancy | 23 (18) |
| Live-born infant | 18 (14) |
| Postnatal death | 26 (20) |
| Stillbirth¶ | 15 (12) |
| Pregnancy termination | 35 (28) |
| Selective reduction of affected twin | 3 (2) |
| Spontaneous loss of pregnancy before 20 wk of gestation | 7 (6) |
| Median gestational age at delivery (IQR) — wk∥ | 31.4 (27.6–34.1) |
*
Percentages may not total 100 because of rounding. IQR denotes interquartile range, and NIHF nonimmune hydrops fetalis.
†
A total of 11 pregnancies resulted from in vitro fertilization and 1 from intrauterine insemination.
‡
Shown are the phenotypic features that were observed on prenatal imaging at the time that exome sequencing was completed.
§
Race and ethnic group were reported by the participant.
¶
Stillbirth was defined as intrauterine fetal death at 20 weeks of gestation or later.
∥
The median and IQR were based on the ongoing pregnancies that did not result in spontaneous loss, termination, or stillbirth.