Preterm birth risk at high altitude in Peru.

OBJECTIVE: High altitude has been implicated in a variety of adverse pregnancy outcomes including preeclampsia and stillbirth. Smaller studies show conflicting data on the association between high altitude and preterm birth (PTB). The objective of this study was to assess the association between altitude and PTB. STUDY DESIGN: A retrospective cohort study was performed using data from the Perinatal Information System, which includes deliveries from 43 hospitals in Peru from 2000 through 2010. Altitude was classified into the following categories: low (0-1999 m), moderate (2000-2900 m), and high (3000-4340 m). The primary outcome was PTB (delivery <37 weeks). Secondary outcomes were cesarean delivery and small for gestational age (SGA). Deliveries less than 23 weeks are not included in the database. χ(2) analyses were performed to compare categorical variables, and a logistic regression was used to calculate the odds ratios and control for confounders. Clustering by hospital was accounted for using generalized estimating equations. RESULTS: A total of 550,166 women were included (68% low, 15% moderate, 17% high altitude). The overall PTB rate was 5.9%, with no difference in the PTB rate among the 3 altitudes (5.6%, 6.2%, 6.8%, P = .13). There was a significant difference in cesarean rates (28.0%, 26.6%, 20.6%, P < .001) with a 34% decreased risk at high vs low altitude adjusted for confounders (adjusted odds ratio, 0.66; 95% confidence interval, 0.51-0.85). There was a difference in SGA (3.3%, 3.6%, 5.0%, P = .02) with a 51% increased risk at high vs low altitude adjusted for confounders (adjusted odds ratio, 1.49; 95% confidence interval, 1.14-1.93). CONCLUSION: High altitude is not associated with PTB. At high altitude, the cesarean rate was reduced and the SGA rate was increased.

Association between maximum temperature and PM2.5 with pregnancy outcomes in Lima, Peru.

BACKGROUND: We have previously documented an inverse relationship between PM2.5 in Lima, Peru, and reproductive outcomes. Here, we investigate the effect of temperature on birth weight, birth weight-Z-score adjusted for gestational age, low birth weight, and preterm birth. We also explore interactions between PM2.5 and temperature. METHODS: We studied 123,034 singleton births in three public hospitals of Lima with temperature and PM2.5 during gestation between 2012 and 2016. We used linear, logistic, and Cox regression to estimate associations between temperature during gestation and birth outcomes and explored possible modification of the temperature effect by PM2.5. RESULTS: Exposure to maximum temperature in the last trimester was inversely associated with both birth weight [ß: -23.7; 95% confidence interval [CI]: -28.0, -19.5] and z-score weight-for-gestational-age (ß: -0.024; 95% CI: -0.029, -0.020) with an interquartile range of 5.32 °C. There was also an increased risk of preterm birth with higher temperature (interquartile range) in the first trimester (hazard ratio: 1.04; 95% CI: 1.001, 1.070). The effect of temperature on birthweight was primarily seen at higher PM2.5 levels. There were no statistically significant associations between temperature exposure with low birth weight. CONCLUSIONS: Exposition to maximum temperature was associated with lower birth weight and z-score weight-for-gestational-age and higher risk of preterm birth, in accordance with much of the literature. The effects on birth weight were seen only in the third trimester.

Pregnancy outcomes associated with Cesarean deliveries in Peruvian public health facilities.

A continuous rise in the rate of cesarean deliveries has been reported in many countries over recent decades. This trend has prompted the emergence of a debate on the risks and benefits associated with cesarean section. The present study was designed to estimate cesarean section rates over time during the period between 2000 and 2010 in Peru and to present outcomes for each mode of delivery. This is a secondary analysis of a large database obtained from the Perinatal Information System, which includes 570,997 pregnant women and their babies from 43 Peruvian public health facilities in three geographical regions: coast, highlands, and jungle. Over 10 years, 558,901 women delivered 563,668 infants weighing at least 500 g. The cesarean section rate increased from 25.5% in 2000 to 29.9% in 2010 (26.9% average; P < 0.01). The rate of stillbirths was lower with cesarean than vaginal deliveries (P < 0.01). On the other hand, and as expected, the rates for preterm births, twin pregnancies, and preeclampsia were higher in women who delivered by cesarean section (P < 0.01). More importantly, the rate of maternal mortality was 5.5 times higher in the cesarean section group than in the vaginal delivery group. Data suggest that cesarean sections are associated with adverse pregnancy outcomes.