Table 1. Maternal Characteristics at Baseline.
| Variable | Early metformin (n = 268)a | Placebo (n = 267)a |
|---|---|---|
| Demographic characteristics | ||
| Age, mean (SD), y | 34.3 (4.9) | 34.3 (4.7) |
| Racial or ethnic groupb | ||
| African/Black | 7 (2.6) | 6 (2.2) |
| Asian | 17 (6.3) | 29 (10.9) |
| Irish Traveller | 11 (4.1) | 2 (0.7) |
| White | 219 (81.7) | 209 (78.3) |
| Other | 14 (5.2) | 21 (7.9) |
| Highest level of education | (n = 268) | (n = 266) |
| Tertiary | 214 (79.9) | 220 (82.7) |
| Secondary | 45 (16.8) | 43 (16.2) |
| Primary | 9 (3.4) | 3 (1.1) |
| In receipt of medical card, No./total (%)c | 63/268 (23.5) | 63/266 (23.7) |
| Private health insurance, No./total (%)c | 126/268 (47) | 116/266 (43.6) |
| Unemployed, No./total (%) | 19/268 (7.1) | 27/266 (10.2) |
| Past history | ||
| Smoking during pregnancy | 17 (6.3) | 17 (6.4) |
| Prior hypertension | 12 (4.5) | 4 (1.5) |
| Nulliparous | 63 (23.5) | 64 (24) |
| Previous obstetrical history available, No./total (%)d | 181/205 (88.3) [n = 181] | 172/203 (84.7) [n = 172] |
| Cesarean delivery | 70 (38.7) | 74 (43) |
| Gestational diabetes | 65 (35.9) | 65 (37.8) |
| Infant with birth weight >4000 g | 57 (31.5) | 44 (25.6) |
| Postpartum hemorrhage | 28 (15.5) | 20 (11.6) |
| Preeclampsia | 24 (13.3) | 23 (13.4) |
| Antepartum hemorrhage | 20 (11) | 15 (8.7) |
| Infant with congenital anomaly | 13 (7.2) | 13 (7.6) |
| Previous stillbirth | 2 (1.1) | 2 (1.2) |
| Physical findings | ||
| BMI at enrollment, median (IQR)e | 29.9 (25.6-33.7) | 30 (26.6-34.3) |
| BMI <30, No./total (%)e | 131/255 (51.4) | 121/251 (48.2) |
| BMI ≥30, No./total (%)e | 124/255 (48.6) | 130/251 (51.8) |
| Gestation at randomization, median (IQR), wk | 27 (25.7-28) | 27 (25.6-28) |
| Duration from randomization to delivery, mean (SD), wk | 13.7 (4.7) | 13.6 (4.3) |
| Duration from randomization to delivery, median (IQR), wk | 12.3 (11-14.1) | 12.4 (11.1-14.2) |
| Systolic blood pressure at randomization, mean (SD), mmHg | 114.9 (9.5) | 114.4 (9.2) |
| Diastolic blood pressure at randomization, mean (SD), mmHg | 68.9 (8) | 68.7 (8.8) |
| Laboratory findings | ||
| Results of 75 g oral glucose tolerance, mean (SD), mmol/L | ||
| Plasma glucose level after overnight fast | 5.2 (0.5) | 5.2 (0.5) |
| Postprandial plasma glucose level at 1 h | 9.4 (1.9) | 9.7 (1.9) |
| Postprandial plasma glucose level at 2 h | 7.1 (1.6) | 7.1 (1.6) |
| Hemoglobin A1c at randomization, mean (SD), mmol/molf | 33 (3.4) [n = 266] | 32.9 (3.5) [n = 265] |
Abbreviation: BMI, body mass index.
Conventional unit conversion factor: to convert glucose to mg/dL, divide by 0.0555.
Numeric values are reported as No. (%) unless otherwise indicated.
Ethnic groups were collected in a closed form. Individuals accounted under the category of Other include the following: Afghan, 3; Bangladeshi, 3; Brazilian, 8; Croatian, 1; Euroasian, 1; Indian, 7; Lithuanian, 1; Nigerian, 1, Pakistani, 3; Filipino, 1; Polish, 3; Romanian, 1; Spanish, 1; and Syrian, 1. Irish Travellers are a nomadic indigenous minority that was formally recognized as an ethnic group by the Irish State in 2017.
Having a medical card indicates that the participant receives all care free of charge; private health insurance indicates that the participant can choose to receive private health care billed to their insurance.
Indicates that percentage values are calculated from 181 participants in the early metformin group and from 172 in the placebo group.
BMI was calculated as weight in kilograms divided by height in meters squared.
Reference range for hemoglobin A1c: 25 to 35 mmol/mol.