Table 1.
Maternal and newborn characteristics of prospective ORCHID study cohort participants eligible for screening after 24 weeks, stratified by completion of OGTT.
| Characteristic | Total Cohort n (%) |
OGTT Complete n = 501 (85.1%) |
OGTT not Done or Incomplete n = 88 (14.9%) |
p-Value |
|---|---|---|---|---|
| Maternal characteristics | ||||
| Age (years) | 589 (100%) | 28.8 ± 5.7 | 27.1 ± 5.0 | 0.008 |
| Ethnicity | < 0.001 | |||
| Non-Indigenous | 324 (55.0%) | 300 (92.6%) | 24 (7.4%) | |
| Aboriginal and Torres Strait Islander | 229 (38.9%) | 169 (73.8%) | 60 (26.2%) | |
| Other high-risk ethnicity † | 36 (6.1%) | 32 (88.9%) | 4 (11.1%) | |
| BMI after 24 weeks (kg/m2) | 589 (100%) | 28.5 ± 6.1 | 28.5 ± 7.2 | 0.92 |
| BMI category ‡ | 0.28 | |||
| Normal or underweight (≤ 28.4) | 330 (56.0%) | 281 (85.2%) | 49 (14.8%) | |
| Overweight (28.5–32.9) | 130 (22.1%) | 115 (88.5%) | 15 (11.5%) | |
| Obese (≥ 33.0) | 129 (21.9%) | 105 (81.4%) | 24 (18.6%) | |
| Parity (prior delivery ≥ 20 weeks) ≥ 1 at enrolment | 401 (68.1%) | 336 (83.8%) | 65 (16.2%) | 0.21 |
| Family history of diabetes § | 181 (30.7%) | 146 (80.7%) | 35 (19.3%) | 0.046 |
| Any antenatal smoking | 162 (27.5%) | 116 (71.6%) | 46 (28.4%) | < 0.001 |
| Antenatal urinary tract infection | 30 (5.1%) | 26 (86.7%) | 4 (13.3%) | 0.80 |
| Previous caesarean delivery ¶ | 70 (17.5%) | 62 (88.6%) | 8 (11.4%) | 0.23 |
| Length of gestation at first antenatal presentation (weeks) | 589 (100%) | 9.8 ± 5.8 | 11.2 ± 7.1 | 0.057 |
| Remoteness classification of health service | 0.220 | |||
| MMM2 | 50 (8.5%) | 48 (96.0%) | 2 (4.0%) | |
| MMM3 | 383 (65.0%) | 320 (83.6%) | 63 (16.4%) | |
| MMM6 | 78 (13.2%) | 72 (92.3%) | 6 (7.7%) | |
| MMM7 | 78 (13.2%) | 61 (78.2%) | 17 (21.8%) | |
| Newborn characteristics | ||||
| Gestational age at delivery (weeks) | 589 (100%) | 39.2 ± 1.5 | 38.8 ± 1.6 | 0.015 |
| Birthweight (g) | 589 (100%) | 3458 ± 531 | 3221 ± 513 | < 0.001 |
| Length (cm) # | 586 (99.4%) | 50.6 ± 2.7 | 49.3 ± 2.5 | < 0.001 |
| Head circumference (cm) †† | 587 (99.7%) | 34.6 ± 1.6 | 34.2 ± 1.5 | 0.025 |
| Sex—Male | 303 (51.4%) | 266 (87.8%) | 37 (12.2%) | 0.056 |
ORCHID = Optimisation of Rural Clinical and Haematological Indicators for Diabetes in pregnancy study; OGTT = 75 g oral glucose tolerance test; BMI = body mass index; MMM = Modified Monash Model. Data include women eligible for screening after 24 weeks gestation; Data are mean ± standard deviation for continuous variables. For categorical variables, data are number (%) of cohort for total cohort or number (%) of total with characteristic for OGTT group. Two-sided t-test p-value reported for comparison between groups for continuous data. Pearson Chi-square test p-value reported for comparison between groups for categorical data, with the exception of differences in remoteness classification, which was compared by Cuzick non-parametric test for trend across ordered groups. † Other high-risk ethnicity includes African (n = 3), Asian (n = 8), Indian (n = 4), Middle-Eastern (n = 3), Maori (n = 13), and Pacific-Islander (n = 5) women. ‡ BMI, maternal weight in kilograms divided by the square of maternal height in meters, calculated after 24 weeks gestation. BMI categorised according to World Health Organization criteria as adjusted by Hyperglycaemia and Pregnancy Outcomes Study Group to account for maternal weight gain by 24 weeks gestation. § Family history of diabetes includes women with a first-degree relative with type 1 or type 2 diabetes or history of GDM. ¶ Previous caesarean delivery includes only women of parity (prior delivery ≥ 20 weeks) ≥ 1 at enrolment. # Length data only available for 498 participants with complete OGTT. †† Head circumference only available for 499 participants with complete OGTT.