Post-conception heat exposure increases clinically unobserved pregnancy losses

Abstract

Evidence of the relationship between temperature during pregnancy and human embryo mortality is limited. Most importantly, the literature lacks causal estimations and studies on early pregnancy losses. Here, we estimate the impact of early pregnancy temperature exposure on the clinically unobserved pregnancy loss rate. We use administrative data of clinically observed pregnancies from more than three decades for Hungary. We apply an empirical approach that allows us to infer the impact of temperature on the clinically unobserved pregnancy loss rate from the estimated effects on the clinically observed conception rate. The results show that exposure to hot temperatures during the first few weeks after the conception week increases the clinically unobserved pregnancy loss rate, whereas exposure to colder temperatures seems to decrease it. Importantly, the temperature-induced changes represent changes in the total number of pregnancy losses rather than a compositional change between clinically observed and clinically unobserved pregnancy losses.

Ecology and age, but not genetic ancestry, predict fetal loss in a wild baboon hybrid zone

“…The rate of fetal loss in Amboseli—approximately 1.4 out of 10 pregnancies (Beehner, Onderdonk, et al (2006) and this study)—is similar to some estimates of miscarriage rates for clinically recognized pregnancies in humans (e.g., ~10%–20% after implantation: Dimitriadis et al, 2020; Pinar et al, 2018). Moreover, abiotic environmental stressors, including high temperatures during pregnancy, have recently gained attention in potentially explaining adverse birth outcomes in humans, such as fetal loss (e.g., Hajdu & Hajdu, 2021; Kanner et al, 2020; Strand et al, 2012; Syed et al, 2022; but see Asamoah et al, 2018). For example, in low‐risk pregnant women in Utah, extreme heat exposure (>90th temperature percentile) increased the odds of stillbirth by ~5‐fold compared to exposure to moderate temperatures (Kanner et al, 2020).…”

The Effect of Prenatal Exposure to Climate Anomaly on Adulthood Cognitive Function and Job Reputation

“…In summary, both the Dutch famine study and our study indicate gestational period as the critical period of cognitive development. In addition to that, climate anomalies can affect heatwave frequency, and prenatal exposure to heatwave can increase risks of miscarriage and stillbirth [ 29 , 30 ]. Climate anomalies also affect infectious disease spreading, e.g., malaria, whose infection during pregnancy has adverse effects on both mother and fetus and may also affect fetus in the long run.…”

Ecology and age, but not genetic ancestry, predict fetal loss in a wild baboon hybrid zone

“…The rate of fetal loss in Amboseli—approximately 1.4 out of ten pregnancies (Beehner, Onderdonk, et al, 2006 and this study)—is similar to some estimates of miscarriage rates for clinically recognized pregnancies in humans (e.g., ∼10-20% after implantation: Dimitriadis et al, 2020; Pinar et al, 2018). Moreover, abiotic environmental stressors, including high temperatures during pregnancy, have recently gained attention in potentially explaining adverse birth outcomes in humans, such as fetal loss (e.g., Hajdu & Hajdu, 2021; Kanner et al, 2020; Strand, Barnett, & Tong, 2012; Syed, O’Sullivan, & Phillips, 2022; but see Asamoah, Kjellstrom, & Ostergren, 2018). For example, in low-risk pregnant women in Utah, extreme heat exposure (>90 th temperature percentile) increased the odds of stillbirth by ∼5-fold compared to exposure to moderate temperatures (Kanner et al, 2020).…”