Table 4.
Evaluation of the association of influenza vaccination and birth outcomes among pregnant women by trimester of vaccination with propensity score matching (PSM) analysis*, post-partum interview, July–December 2014, Managua, Nicaragua.
| Birth outcomes | Influenza vaccine 2014 season |
|||||
|---|---|---|---|---|---|---|
| Vaccinated in first trimester (n = 280) | Vaccinated in second trimester (n = 1600) | Vaccinated in third trimester (n = 1162) | ||||
| aOR (95% CI) | aOR (95% CI) ×1000sim*** | aOR (95% CI) | ||||
| Small for gestational age (SGA) | 0.90 | (0.40; 2.03) | 1.00 | (0.86; 1.17) | 0.83 | (0.55; 1.25) |
| Preterm birth** (PTB) | 1.67 | (0.73; 3.83) | 0.87 | (0.75; 0.99) | 0.66 | (0.45; 0.96) |
| Low birth weight (LBW)** | 1.71 | (0.55; 5.26) | 0.80 | (0.64; 0.97) | 0.64 | (0.38; 1.09) |
aOR = Adjusted Odds Ratio.
Propensity Score Models adjusted for age, race, education level, type of fuel used for cooking, number of people in the household, reporting receiving at least one tetanus vaccine, number of antenatal visits, Fe and vitamin B12 consumption during pregnancy, albendazol consumption during pregnancy, calcium consumption during pregnancy, aspirin consumption during pregnancy, alcohol consumption before pregnancy, body mass index (BMI) at first antenatal visit, number of parturitions, and reporting at least one chronic condition (obesity, diabetes, asthma, renal disease, liver disease, blood disease, neurologic disease).
Models adjusted for delivery hospital, hospitalization during pregnancy for any specific complication (preeclampsia, eclampsia, hemorrhage, sepsis, urinary infection, diabetes, severe acute respiratory infection), reporting at least one episode of influenza-like illness during pregnancy (ILI), alcohol consumption before pregnancy, number of parturitions, sex of the baby, and influenza circulation.
Based on 1000 simulations when requirement one-to-two vaccinated-to-unvaccinated proportion for good propensity score matching was not met; point estimate and lower and upper confidence interval represent 50th, 25th and 97.5th percentiles of point estimates (n = 1000), respectively.