Association of hemoglobin values at booking with adverse maternal outcomes among Peruvian populations living at different altitudes.

OBJECTIVE: To determine hemoglobin values associated with adverse maternal outcomes among Peruvian populations at different altitudes. METHODS: A retrospective cohort study was conducted using data from the Perinatal Information System. Adverse maternal outcomes were assessed. RESULTS: Risk of pre-eclampsia increased at maternal hemoglobin levels above 14.5 g/dL (OR 1.27; 95% CI, 1.18-1.36) or below 7.0 g/dL (OR 1.52; CI 95%, 1.08-2.14). Altitude above 2000 m reduced risk (OR 0.65; 95% CI 0.62-0.68). Risk of postpartum hemorrhage (PPH) increased with moderate/severe anemia (OR 6.15; 95% CI, 3.86-9.78) and at moderate altitudes (OR 1.26; 95% CI, 1.12-1.43). Mild anemia at any altitude was associated with reduced risk of pre-eclampsia (OR 0.85, 95% CI, 0.81-0.89) and PPH (OR 1.01; 95% CI, 0.88-1.15). Risk of premature rupture of membranes was reduced at high hemoglobin values. Maternal mortality increased at hemoglobin levels below 9.0 g/dL (OR 5.68; 95% CI, 2.97-10.80) and above 14.5 g/dL (OR 2.18; 95% CI, 1.22-3.91). Maternal mortality increased at moderate altitudes (OR 29.2; 95% CI, 2.62-324.60) and high altitudes (OR 66.4; 95% CI, 6.65-780.30) when hemoglobin levels were below 9.0 g/dL. CONCLUSION: Elevated altitude and hemoglobin levels influence maternal outcomes.

Maternal hemoglobin concentration and adverse pregnancy outcomes at low and moderate altitudes in Peru.

OBJECTIVE: To identify associations of maternal hemoglobin (Hb) with perinatal outcomes at low and moderate altitudes in Peru. METHODS: Study of records with sequential information using perinatal database system. The study included 295 651 pregnant women with their products. Using multiple logistic regression analysis, we estimated the probability of stillbirths, preterm and small for gestational age (SGA) births associated with maternal Hb levels at low (0-1999 m) and moderate altitudes (2000-2999 m). RESULTS: Maternal Hb decreased as pregnancy progressed from first to third trimester at both altitudes. Hb was higher at moderate than at low altitude (p < 0.001). Risks for stillbirths increased with low maternal Hb (odds ratio [OR]: 1.39 for Hb 9-9.9; OR: 1.84 for Hb 8-8.9; OR: 3.25 for Hb 7-7.9; and OR: 7.8 for Hb <7 g/dl); with Hb higher than 14.5 g/dl (OR: 1.31) and with altitudes ≥ 2000 m (OR: 1.2). High preterm rates were also observed with low Hbs (OR: 1.16 for Hb 9-9.9; OR: 1.64 for Hb 8-8.9; OR: 2.25 for Hb 7-7.9; and OR:2.87 for Hb<7 g/dl) and with Hb higher than 14.5 g/dl (OR: 1.14). High SGA rates were observed in neonates with maternal Hb of 7-7.9 (OR: 1.35) and <7 g/dl (OR:1.57), and higher than 14.5 g/dl (OR: 1.33), and with moderate altitudes (OR: 1.12). The cut-off points for lower risks of stillbirth and preterm births was 10 g/dl, and for SGA 9 g/dl of hemoglobin. CONCLUSION: Low and high maternal Hb levels and moderate altitude were independent risk factors for adverse perinatal outcomes.

Stillbirth rates in Peruvian populations at high altitude.

OBJECTIVE: To compare the stillbirth rates in 4 cities at different altitudes in Peru. METHODS: The stillbirth rates from a sample of 22,662 births recorded in the Perinatal Information System database were analyzed between 2005 and 2006 for the cities of Lima (150 m), Huancayo (3280 m), Cuzco (3430 m), and Puno (3850 m). RESULTS: Stillbirths were higher at high altitude (>3000 m) (OR 4.82; CI, 3.05-7.72) compared with low altitude. The effect of altitude was observed after controlling for socioeconomic (OR 4.29; CI, 2.61-6.93), demographic and biological (OR 4.18; CI, 2.65-6.77), maternal health care (OR 4.72; CI, 2.96-7.61), and fetal factors (OR 3.96; CI, 2.48-6.45). Inhabitants from the southern Andes demonstrated a protective effect on stillbirth rate compared with the central Andes, which may be due to an ancestry effect with longer multigenerational residence in the southern Andes population. CONCLUSION: Stillbirth rate is higher at high altitude compared with low altitude.