Linking Climate Change With Pregnancy Outcomes

2020 Data from PMA Ethiopia

Kathryn Grace, Matt Gunther, Jiao Yu - University of Minnesota

Highlights

  • Heat exposure during pregnancy increases risks for spontaneous miscarriage and stillbirth.
  • However, women develop strategies for mitigating risks over time.
  • We find evidence that women who have lived in a hot place for many years are less likely to experience negative birth outcomes following heat exposure during pregnancy.

2020 Data from
PMA Ethiopia

2020 Data from PMA Ethiopia

Women report all pregnancy outcomes within 3 years

2020 Data from PMA Ethiopia

Must have resided near sample cluster (•) for 2 years (centroid displaced up to 10 km)

2020 Data from PMA Ethiopia

Beyond 2 years, women report how long they have lived in their current region

Measuring Heat Exposure

Addressing challenges to spatial and temporal aggregation

Measuring Heat Exposure

We use a daily maximum temperature record, CHIRTS Tmax (0.05 arc-degree resolution, 1980-2020)

Measuring Heat Exposure

For a given day during a pregnancy, we get a spatially precise measure of the Tmax readings within a 10km buffer around the sample cluster centroid
Lifetime exposure is less spatially precise - we take an average of all Tmax readings in the region on that day, weighted for the population density at each reading

Measuring Heat Exposure

It’s especially important to weight regional means by population density!

Measuring Heat Exposure

We create indicators at three heat thresholds for each day, 1980-2020.

We identify a heatwave whenever a threshold is passed for at least 3 consecutive days

  • 0-2 hot days = 0 heatwaves
  • 3 hot days = 1 heatwave
  • 4 hot days = 1.33 heatwaves, etc

Lifetime Heat Exposure by Region

One for each of 6 heat measures. Lifetime exposure to 30° C Days looks like this:

Likelihood of miscarriage / stillbirth

Analysis of the interaction between lifetime heat exposure (tertiles) and pregnancy heat exposure

Binary logistic regression. Controls include: mother’s age, partnership status, educational background, household wealth, religion, pregnancy intentions at conception, and clustered fixed effects for sample strata (region + urban).

Results: Heat as Days >30° C

Thanks!