Table 1.
Small-for-Gestational-Age (<2 Standard Deviations) Newborns Associated With Placenta Previa After Adjustment for Socio-demographics and Pregnancy Characteristics in Nulliparous and Multiparous Women Among Singleton Birthsa During 2000–2010 in Finland
| SGA | NULLIPARA | *Differences with Model x | MULTIPARA | *Differences with Model x |
|---|---|---|---|---|
| OR (95 % CI) | OR (95 % CI) | |||
| Model 1 unadjusted | 0.85 (0.59–1.23) | - | 2.47 (1.80–3.39) | - |
| Model 2 adjusted by maternal age | 0.81 (0.56–1.16) | 1: - | 2.35 (1.71–3.23) | 1: 8.2% |
| Model 3 adjusted by age and parity | NA | 2: - | 2.43 (1.76–3.34) | 2: - |
| Model 4 adjusted by Model 3 + prior preterm birth | NA | 2: - | 2.31 (1.68–3.18) | 3: 8.4% |
| Model 5 adjusted by Model 3 + prior caesarean section birth | NA | 2: - | 2.33 (1.69–3.21) | 3: 7.0% |
| Model 6 adjusted by Model 3+ prior SGA newborn | NA | 2: - | 2.22 (1.60–3.07) | 3: 14.7% |
| Model 7 adjusted by Model 3+ In vitro fertilization | 0.82 (0.57–1.18) | 2: - | 2.43 (1.77–3.34) | 3: 0% |
| Model 8 adjusted by Model 2 or 3 + smoking | 0.81 (0.56–1.16) | 2: 0% | 2.36 (1.71–3.25) | 3: 4.9% |
| Model 9 adjusted by Model 2 or 3 + preeclampsia | 0.81 (0.57–1.17) | 2: 0% | 2.36 (1.71–3.25) | 3: 4.9% |
| Model 10 adjusted by Model 2 or 3 + all confoundersb | 0.81 (0.57–1.17) | 2: 0% | 2.08 (1.50–2.89) | 3: 24.5% |
Cases with major congenital anomalies were excluded.
In nulliparous women OR of SGA adjusted for maternal age, smoking, IVF, socioeconomic status and preeclampsia.
In multiparous women OR of SGA adjusted for maternal age, parity, prior preterm birth, prior cesarean birth, prior SGA newborn, prior preeclampsia, smoking, IVF, socioeconomic status and preeclampsia.
(The contribution of each factor was measured by the percentage reduction in the odds ratio of placenta previa compared to Model 2 by using formula (OR Model 2 or 3 − OR Model x) / (OR Model 2 or 3 − 1).