Table 5.
Pill Adherence, Mode of Delivery, and Neonatal Characteristics by Vitamin D Supplementation Group
| a. Circulating 25(OH)D (nmol/L) by Trimester Stratified by Treatment Group
| |||
|---|---|---|---|
| Treatment Group | Baseline 25(OH)D Mean ± SD | 2nd Trimester1 Mean ± SD | 1 month prior delivery Mean ± SD |
| 400 IU | 61.2 ± 27.1 | 76.1 ± 27.5 | 81.2 ± 35.9 |
| 2000IU | 57.5 ± 22.4 | 84.2 ± 23.0 | 102.6 ± 36.4 |
| 4000IU | 59.8 ± 25.4 | 98.6 ± 27.3 | 114.2 ± 35.5 |
| p-value | 0.5 | <0.0001 | <0.0001 |
| b. Circulating 25(OH)D (nmol/L) By Trimester Stratified by Treatment Group and Race/Ethnicity
| ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 400 IU | 2000 IU | 4000 IU | ||||||||||
| Characteristic | Baseline 25(OH)D Mean ± SD | 2nd Trimester Mean ± SD | 1 month prior to delivery Mean ± SD | Δ baseline to 1 month prior2 (p-value) | Baseline 25(OH)D Mean ± SD | 2nd Trimester Mean ± SD | 1 month prior to delivery Mean ± SD | Δ baseline to 1 month prior (p-value) | Baseline 25(OH)D Mean ± SD | 2nd Trimester Mean ± SD | 1 month prior to delivery Mean ± SD | Δ baseline to 1 month prior (p-value) |
| African American | 37.3 ± 17.1 | 48.8 ± 21.1 | 49.4 ± 28.4 | 12.7(0.009) | 41.0 ± 19.1 | 72.2± 28.4 | 91.2 ± 45.1 | 49.4 (<0.0001) | 40.7 ± 20.1 | 81.0 ± 26.4 | 97.8 ± 42.4 | 57.4 (<0.0001) |
| Hispanic | 59.1 ± 21.6 | 76.9 ± 21.7 | 79.5 ± 30.3 | 20.3 (<0.0001) | 59.2 ± 18.9 | 85.2 ± 16.8 | 102.1 ± 28.7 | 42.1 (<0.0001) | 63.3 ± 27.6 | 101.4 ± 28.2 | 121.1 ± 30.9 | 60.1 (<0.0001) |
| Caucasian | 81.3 ± 23.8 | 95.2 ± 20.6 | 106.9 ± 26.4 | 25.0 (<0.0001) | 71.9 ± 19.0 | 94.9 ± 18.3 | 115.7 ± 31.8 | 44.4 (<0.0001) | 71.3 ± 17.3 | 109.8 ± 19.2 | 120.4 ± 29.7 | 50.4 (<0.0001) |
| p-value | <0.0001 | <0.0001 | <0.0001 | <0.0001 | <0.0001 | 0.02 | <0.0001 | <0.0001 | 0.008 | |||
| c. Intact PTH (pmol/L) by Trimester Stratified by Treatment Group
| |||
|---|---|---|---|
| Treatment Group | Baseline PTH Mean ± SD | 2nd Trimester3 Mean ± SD | 1 month prior delivery Mean ± SD |
| Control | 1.9 ± 1.0 | 1.9 ± 1.0 | 2.2 ± 1.3 |
| 2000IU | 1.8 ± 0.9 | 1.7 ± 0.9 | 2.1 ± 1.1 |
| 4000IU | 1.8 ± 1.1 | 1.6 ± 0.8 | 1.9 ± 1.1 |
| p-value | 0.5 | 0.1 | 0.1 |
| d. PTH (pmol/L) By Trimester Stratified by Treatment Group and Race/Ethnicity
| |||||||||
|---|---|---|---|---|---|---|---|---|---|
| 400 IU | 2000IU | 4000IU | |||||||
| Characteristic | Baseline PTH Mean ± SD p-value | 2nd Trimester Mean ± SD p-value | 1 month prior Mean ± SD p-value | Baseline PTH Mean ± SD p-value | 2nd Trimester Mean ± SD p-value | 1 month prior Mean ± SD p-value | Baseline PTH Mean ± SD p-value | 2nd Trimester Mean ± SD p-value | 1 month prior Mean ± SD p-value |
| African American | 2.5 ± 1.2 | 2.6 ± 1.2 | 3.1 ± 1.8 | 2.1 ± 1.1 | 2.0 ± 0.9 | 2.3 ± 1.3 | 2.0 ± 0.9 | 1.9 ± 0.9 | 2.3 ± 1.1 |
| Hispanic | 1.8 ± 0.9 | 1.8 ± 0.7 | 2.0 ± 1.0 | 1.7 ± 0.9 | 1.8 ± 1.0 | 2.2 ± 1.1 | 1.8 ± 1.1 | 1.5 ± 0.7 | 1.7 ± 0.9 |
| Caucasian | 1.6 ± 0.9 | 1.4 ± 0.8 | 1.7 ± 1.0 | 1.6 ± 0.7 | 1.5 ± 0.7 | 1.9 ± 1.0 | 1.7 ± 1.2 | 1.6 ± 0.8 | 1.7 ± 1.3 |
| p-value | 0.001 | <0.0001 | 0.0002 | 0.01 | 0.055 | 0.3 | 0.6 | 0.06 | 0.06 |
Mode of delivery was categorized a priori as either a vaginal delivery (defined as spontaneous vaginal delivery or assisted vaginal delivery [which included use of forceps or vacuum extraction]) or cesarean section (further subdivided as cesarean following labor, cesarean without labor, and repeat elective cesarean) Primary cesarean section included women who had undergone a cesarean section with or without labor for either a maternal or fetal indication and did not include women who underwent a repeat, elective cesarean section.
Pill Adherence Measure was calculated as follows: the number of pills taken divided by the number of pills predicted to have been taken based on the number of days between visits. Of note, women who missed a study visit had additional vitamin D study pills delivered to them to ensure a continued supply of the study drug. If a woman missed two consecutive visits, she exited the study.