TABLE 1.
Placental, maternal, and neonatal characteristics in adult women carrying multiple fetuses and their neonates and pregnant adolescents and their neonates1
| Multiples cohort | Adolescents cohort | P value | |
|---|---|---|---|
| Placental characteristics | (n = 110) | (n = 114) | |
| Gestational age (wk) | 35.2 [34.5, 35.6] | 40.2 [39.7, 40.2] | <0.001 |
| Placenta weight per fetus2 (g) | 297 [278.2, 316.0] | 586 [577.9, 622.6] | — |
| Sum placental weight2 (g) | 667 [606.9, 738.7] | 586 [577.9, 622.6] | — |
| p[Fe] (μg/g wet weight) | 94.3 [59.3,150.0] | 67.8 [51.8, 88.7] | 0.31 |
| Maternal characteristics | (n = 54) | (n = 114) | |
| Age (y) | 30 [29.4, 32.1] | 17.4 [17.2, 18.1] | <0.001 |
| Race3 (% Black women) | 22 | 64 | <0.001 |
| Ethnicity3 (% Hispanic women) | 7 | 26 | 0.002 |
| ppBMI (kg/m2) | 26.1 [26.4, 31.0] | 23.0 [23.7, 25.8] | 0.001 |
| GWG4 (kg) | 18.6 [17.1, 22.2] | 18.2 [16.7, 19.4] | 0.22 |
| Parity <1 (%) | 37 | 79 | <0.001 |
| Prenatal supplement use5, >2 times/wk (%) | 90 (44/49) | 77 (82/106) | 0.07 |
| Current cigarette use (%) | 6 (3/52) | 7 (7/107) | 0.80 |
| Delivery anemia6 (%) | 44 | 33 | 0.20 |
| Neonatal characteristics | (n = 110) | (n = 114) | |
| Birth weight (kg) | 2.2 [2.1, 2.3] | 3.3 [3.2, 3.4] | <0.001 |
| Birth length (cm) | 47.0 [44.7, 46.4] | 51.5 [50.9, 51.8] | <0.001 |
| Sex (% male) | 43 | 51 | 0.19 |
| C-section (%) | 73 | 11 | <0.001 |
| Placenta weight/birth weight2 | 0.13 [0.13, 0.15] | 0.18 [0.18, 0.19] | — |
| Anemic7 (%) | 14 | 25 | 0.09 |
Data presented as median [95% CI] or %. GWG, gestational weight gain; ppBMI, prepregnancy body mass index; p[Fe], placental iron concentration.
Differences between placental weight or placental efficiency were not compared between cohorts because placental weight measurements in the adolescent cohort were taken before trimming and in the multiples cohort after trimming took place.
Self-reported maternal race (Black individual or White individual) and ethnicity (Hispanic individual or non-Hispanic individual).
Gestational weight gain categories were determined using the Institute of Medicine categories with adjustment for gestational age at delivery. For the adolescent cohort, recommended gestational weight gain was 12.7–18.1 kg for underweight women, 11.3–15.9 kg for normal-weight women, 6.8–11.3 kg for women with overweight, and 5.0–9.1 kg (11–20 lb) for women with obesity. For the multiples cohort, recommended gestational weight gain was 22.7–28.1 kg for underweight women, 16.8–24.5 kg for normal-weight women, 14.1–22.7 kg for women with overweight, and 11.3–19.1 kg for women with obesity.
Self-reported use of prenatal supplements that typically contained 27 mg of iron per day or intake of 2 pediatric chewable supplements that provided 20 mg of iron per day.
Prevalence of anemia at delivery. Maternal anemia was defined as hemoglobin concentration <11.0 g/dL in the first and third trimesters and <10.5 g/dL in the second trimester [37].
Neonatal anemia was defined as umbilical cord Hb concentration <13.0 g/dL [37].