Preterm birth risk at high altitude in Peru

Area of Science:

• Obstetrics and Gynecology
• Environmental Health
• Perinatal Epidemiology

Background:

• High altitude exposure is linked to adverse pregnancy outcomes.
• Previous studies on high altitude and preterm birth (PTB) have yielded conflicting results.
• Understanding altitude's impact on pregnancy is crucial for public health initiatives.

Purpose of the Study:

• To investigate the association between high altitude and preterm birth (PTB).
• To examine secondary outcomes including cesarean delivery and small for gestational age (SGA) births in relation to altitude.

Main Methods:

• A retrospective cohort study analyzed data from 550,166 deliveries across 43 hospitals in Peru (2000-2010).
• Altitude was categorized as low (0-1999 m), moderate (2000-2900 m), and high (3000-4340 m).
• Logistic regression and generalized estimating equations were used to analyze PTB, cesarean delivery, and SGA, controlling for confounders.

Main Results:

• No significant difference in PTB rates was observed across low, moderate, and high altitudes (5.6% vs. 6.2% vs. 6.8%, P = .13).
• Cesarean delivery rates were significantly lower at high altitudes (20.6%) compared to low altitudes (28.0%), with a 34% reduced risk (aOR, 0.66; 95% CI, 0.51-0.85).
• Small for gestational age (SGA) rates were higher at high altitudes (5.0%) compared to low altitudes (3.3%), indicating a 51% increased risk (aOR, 1.49; 95% CI, 1.14-1.93).

Conclusions:

• High altitude is not associated with an increased risk of preterm birth.
• Pregnancy at high altitudes is linked to a reduced rate of cesarean deliveries.
• Increased risk of delivering a small for gestational age (SGA) infant is associated with high altitude pregnancies.