Table 1 Impact of early pregnancy temperature exposure on the clinically unobserved pregnancy loss rate.

From: Post-conception heat exposure increases clinically unobserved pregnancy losses

Daily mean temperature (°C)

Coeff

SE

p value

95% CI

below –5

–0.036

(0.087)

0.681

[− 0.218; 0.146]

–5 to 0

–0.195

(0.072)

0.013

[− 0.345; − 0.045]

0 to 5

–0.088

(0.062)

0.173

[− 0.217; 0.042]

5 to 10

–0.124

(0.046)

0.015

[− 0.220; − 0.027]

10 to 15

0.016

(0.033)

0.628

[− 0.054; 0.087]

15 to 20

Ref. cat

   

20 to 25

0.036

(0.045)

0.437

[− 0.059; 0.131]

over 25

0.225

(0.049)

0.000

[0.122; 0.327]

  1. The coefficients show the impact of early pregnancy temperature exposure by temperature category. The coefficients represent the effect of one additional day with a given mean temperature on the clinically unobserved pregnancy loss rate relative to a day with a mean temperature of 15–20 °C. The early pregnancy period is defined as a six-week-long period starting after the week of conception. The estimations come from Eq. (9). The outcome variable is the clinically observed conception rate per week per 100,000 women aged 16–44 years, which is calculated using conceptions that end in clinically observed pregnancy outcomes. The impacts of temperature exposure on the clinically unobserved pregnancy loss rate are obtained by multiplying the estimated temperature coefficients by − 1. The model has county-by-year fixed effects, region-by-calendar-week fixed effects, and region-by-calendar-week-specific quadratic time trends. Precipitation, pre-conception weather, and the share of non-working days are controlled for. We weight by the counties’ average female population size (aged 16–44 years) between 1981 and 2015. Standard errors are clustered by county and time.
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