Table 4.
Recurrence of preterm birth at < 37, < 35 and < 32 weeks and subtypes in second pregnancy based on preterm birth at less than 37, less than 35, and less than 32 weeks in the first pregnancy, respectively: Missouri, 1989 to 1997
| Preterm birth in the first pregnancy | Preterm birth in second pregnancy, adjusted OR (95% CI) | ||
|---|---|---|---|
| All preterm births | Spontaneous births | preterm Medically preterm indicated births | |
| Preterm birth at < 37 wks | |||
| Preterm birth at < 37 wks | 2.9 (2.8, 3.0) | 2.7 (2.5, 2.9) | 3.3 (3.1, 3.6) |
| Spontaneous preterm birth | 2.8 (2.7, 3.0) | 3.2 (3.1, 3.4) | 1.7 (1.5, 1.9) |
| Medically indicated preterm birth | 3.0 (2.8, 3.3) | 1.0 (0.9, 1.2) | 7.7 (7.0, 8.5) |
| Preterm birth at < 35 wks | |||
| Preterm birth at < 35 wks | 3.6 (3.4, 3.9) | 3.1 (2.8, 3.4) | 4.8 (4.3, 5.4) |
| Spontaneous preterm birth | 3.3 (3.0, 3.6) | 3.6 (3.2, 4.0) | 2.5 (2.1, 3.0) |
| Medically indicated preterm birth | 4.6 (4.0, 5.2) | 1.6 (1.3, 2.1) | 10.6 (9.1, 12.4) |
| Preterm birth at < 32 wks | |||
| Preterm birth at < 32 wks | 4.9 (4.2, 5.7) | 4.1 (3.4, 4.9) | 6.5 (5.2, 8.0) |
| Spontaneous preterm birth | 4.5 (3.8, 5.4) | 4.6 (3.7, 5.6) | 4.3 (3.1, 5.8) |
| Medically indicated preterm birth | 5.8 (4.5, 7.4) | 2.7 (1.8, 4.1) | 11.3 (8.4, 15.1) |
ORs are adjusted for maternal age (second birth), education (second birth), marital status, race/ethnicity, smoking and alcohol use, prepregnancy body mass index, and lack of or late initiation of prenatal care and interpregnancy interval. OR, Odds ratio; CI, confidence interval.
Modified from Ananth et al,18 with permission.
Ananth CV, Getahun D, Peltier MR, Salihu HM, Vintzileos AM. Recurrence of spontaneous versus medically indicated preterm birth. Am. J. Obstet. Gynecol. 2006;195:643–50.