Table 1.
Summary of the clinical characteristics of participants.
| Term (>36 + 6 weeks) | Late preterm (34–36 + 6 weeks) | Early preterm (<34 weeks) | |
|---|---|---|---|
| (n = 76) | (n = 12) | (n = 6) | |
| Age (years, mean ± SD) | 32.5 ± 5.5 | 34.4 ± 5.1 | 32.5 ± 4.6 |
| BMI at ∼10 weeks (mean ± SD) |
26.4 ± 5.7 | 26.0 ± 4.8 | 26.2 ± 6.0 |
| Smoked during pregnancy (n, %) | 5, 6.6% | 0, 0% | 1, 17% |
| Ethnicity (n, %) | |||
| White | 46, 61% | 7, 58% | 5, 83% |
| Afro-Caribbean | 17, 22% | 2, 17% | 1, 17% |
| Asian | 13, 17% | 3, 25% | 0, 0% |
| History (n, %) | |||
| Previous SPTB <34 weeksa |
36, 47% | 3, 25% | 4, 67% |
| Previous SPTB ≥34 weeksb |
9, 12% | 7, 58% | 1, 17% |
| Previous LMC | 31, 41% | 2, 17% | 1, 17% |
| Sample donated | |||
| 12–20 weeks (n, %) | 66, 87% | 9, 75% | 5, 83% |
| Progesterone | 0, 0% | 0, 0% | 2, 33% |
| Ultrasound indicated cerclage |
|||
| (Cervix <25 mm; n, %) | 2, 2.6% | 5, 42% | 1, 17% |
| Elective cerclage (n, %) | 12, 16% | 0, 0% | 3, 50% |
| Cervico-vaginal fetal fibronectin |
|||
| >50 ng/mL detected at 22–24 |
|||
| weeks (n, %) | 6, 7.9% | 5, 42% | 3, 50% |
| Shortest cervical length (mm, mean ± SD) | 29.5 ± 4.4 | 24.8 ± 6.8 | 26.5 ± 8.0 |
| Positive result in infection screen | |||
| (n, %)c | 29, 38% | 2, 17% | 1, 17% |
SPTB spontaneous preterm birth, LMC late miscarriage (16–23 + 6 weeks).
a
One or more SPTB <34 weeks. These women may also have had LMC or SPTB ≥34 weeks.
b
One or more SPTB ≥34 weeks. These women may also have had LMC.
c
Infections screened for bacterial vaginosis, Trichomonas vaginalis, gonococcus, chlamydia, group B Streptococcus, candidiasis and asymptomatic bacteriuria.