Potential influence of temperature and precipitation on preterm birth rate in Puerto Rico

Abstract

The preterm birth (PTB) rate for singletons born in the tropical Caribbean island Puerto Rico increased from 11.3% in 1994, which was comparable to rates in the U.S., to as high as 18.3% in 2006 before decreasing to 15.5% in 2012. A few studies have reported that weather extremes are associated with higher risk of preterm birth, however, the effects of ambient temperature and precipitation has not been well examined in Puerto Rico. We compiled child birth data from the National Center for Health Statistics and weather data from the National Oceanic and Atmospheric Administration from 1994 to 2012. We explored the association between the weather factors and PTB rates with a distributed lag non-linear model (DLNM). We did not find direct association of lagged effect of temperature on birth outcome over monthly timescales. Both high intensity and frequency of precipitation and high frequency of storm and flood events are associated with increased risk of PTB rates. While the weather factors do not explain the marked increase and decrease in PTB rate, we emphasize the negative effects on PTB from weather extremes particularly precipitation in Puerto Rico.

Associations between high temperatures in pregnancy and risk of preterm birth, low birth weight, and stillbirths: systematic review and meta-analysis

“…The high threshold level signals temperatures above the 75th, 90th, and 99th centile, for example, depending on individual studies. Fourteen studies did not report outcomes in any of these four categories and were not included in forest plots or summary measures 293031323334353637383940414243…”

“…Fourteen studies did not report outcomes in any of these four categories and were not included in forest plots or summary measures. [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43] In studies that reported several significant outcomes, we selected the measure with the highest effect size. Given that the lag or temperature threshold at which impacts are largest is unknown and will probably vary between populations, the highest estimate might be the true highest level, rather than the result of multiple testing.…”

Universal Thermal Climate Index (UTCI) and adverse pregnancy outcomes in Ahvaz, Iran

“…Some studies have reported a possible relation between preterm birth, stillbirth, and low birth weight with ambient temperature [ 4 ]. For example, Yu et al reported the effect of extreme weather on preterm birth in the tropical island of Puerto Rico [ 5 ]. Apparently, increase in temperature in the warm season is significantly more dangerous than the cold season [ 6 ], and studies have reported a positive relation between preterm birth and heat wave exposure during pregnancy [ 7 , 8 ].…”

Time series analysis of total and direct associations between high temperatures and preterm births in Detroit, Michigan

“…In this DAG, AT is the exposure of interest and PTB the outcome of interest. Given suspected associations between PTB and precipitation23 and between PTB and vitamin D, for which one source is solar radiation,24 as well as causal meteorological relationships between AT, solar radiation and precipitation via a parent weather system, precipitation and solar radiation are potential confounders of the AT-PTB association. In this DAG, primary and secondary air pollutants are the hypothesised mediators of the temperature-PTB association given that: (1) they have been associated with the health outcome in other locations3 and in this data set in the third trimester,4 (2) high temperature enhances the rate of ground-level ozone formation and (3) power plant emissions increase when temperatures rise to accommodate additional demand for air conditioning 25.…”