O&G Forum

morbidity and mortality. Bryson et al reported a cyclic interaction between physical health during pregnancy and food security amongst Ugandan women: illness during pregnancy decreased food procurement and consequent undernutrition intensi ed illness, making it even harder for women to access food.11 Extreme weather events are expected to increase health risks for pregnant women in rural areas making it easier to enter and harder to exit the cycle of ill health and poor food security. e world’s freshwater resources, particularly natural drinking sources, are believed to be threatened by the e ects of climate change. Groundwater, crop soils and many rivers are likely to become increasingly saline from higher tidal waves and storm surges. High salinity levels in drinking water impact the health of populations. Khan et al (2011) reported higher rates of preeclampsia and gestational hypertension in women living in the southwest coast of Bangladesh compared with non-coastal pregnant women due to saline contamination of drinking water.12 Air Pollution Air pollution is among the top 10 threats to global health as listed by theWHOand the fourth leading risk factor for earlydeathworldwide in2019.13,14Ambient air pollution is a dynamicmixture of ultra ne, ne and coarse particles as well as various gases, which results from fossil fuel combustion, industrial processes and waste incineration. Household air pollution is generated from cooking with low quality fuels and technologies. e World Health Organisation (WHO) recommended that safe level for particulate matter (PM) 2.5 is 5 micrograms per cubic of air as an annual average.15 Approximately 93% of children live in environments with air pollution levels above the WHO guidelines. Residential cooking contributes as much as 12% of global PM 2.5. ere is mounting evidence that several aspects of reproduction are impacted by air pollution. ese include decreased live birth rates, increased rates of miscarriage and fertility problems. While the mechanism of action is not well understood, an association has been drawn between exposure to PM 2.5 and decreased human fecundity with possible explanations include reduced sperm quality and an inverse relationship between oocyte numbers, maturation and even fertilisation rates.16 A recent systematic review speci cally focusing on a US population noted a signi cant association between increased PM2.5 and heat exposure with worse birth outcomes.17 Exposure to PM 2.5 is associated with an increased risk in preterm birth and low birth weight in 79% and 86% of the studies respectively. Additionally air pollution has signi cant negative e ects on the cardiovascular system. Meta-analyses have shown signi cant positive associations between the incidence of preeclampsia and exposure to PM 2.5 and nitrogen dioxide.18 Pollutants are believed to adversely a ect trophoblast invasion and placental vascularisation resulting in placental dysfunction. Heat-related impact Physiological changes associated with pregnancy creates a speci c vulnerability to climate change. Pregnant women are at greater risk for heat-related illnesses than their non-pregnant counterparts as they are less able to thermoregulate. Increased fat deposition and the decreasedbody-surface-area tobody-mass ratioreduces thepregnant mother’s ability to lose heat to the environment. Mothers exposed to extreme heat during pregnancy are at higher risk of stillbirths, preterm births and delivering low birth weight infants.19 Moodley et al (2021) found a 4% increase in pregnancy loss for every 1 degree increase in temperature in a rural setting in SouthAfrica.20Maternal exposure to heat stress also increases one’s risk for dehydration and renal failure. Dehydration in early pregnancy adversely a ects fetal growth while it is associated with preterm birth in later gestations. In a systemic review by Bekkar et al, the risk of pre-term birth was increased by 11.6% per 5.6°C increase in temperature.17 Term birth weight decreased by 16g per IQR temperature increase, and the risk for stillbirth increased by 6% per 1°C increase the week before delivery during summer. Maternal hyperthermia in early pregnancy is associated with increased risk of congenital malformations such as neural tube and cardiac defects in the fetus. Increased heat is already a reality for many – including people living in informal settlements where houses are o en built of corrugated iron with little or no ventilation. Flooding and droughts Droughts and oods reduces access to reliable water sources resulting in dehydration. Additionally, droughts and oods decrease food security, which impacts on maternal nutrition. Increased rates of preterm birth and low birth weight babies were reported following the Hurricane Katrina in 1997. Evidence from the Iowa ood, the El Nino ood as well as the Yangtze River Flood indicate that prenatal maternal stress caused by a natural disaster such as ooding are associated with a higher risk of cognitive impairment in childhood.21 e severity and e ect is proportional to the duration of exposure and the severity of ooding. Vector borne illnesses Increasing temperature is also associated with increases in the rates of malaria, dengue and Zika which are more harmful to pregnant compared to non-pregnant women as well as their fetuses. Malaria, Dengue fever and Lyme disease are of the most common vector- borne illnesses, where pregnant women are at an increased risk of developing severe malaria. Vectors, which are all ectotherms (cold- blooded) breed easier in warmer climates, as seen in SSA. Predicting the spread and e ect of vector-borne disease is a very di cult predict as it has many variables including aggressiveness of climate control, and vaccination rollout and usage. Spread of mosquitos such as A. aegypti is limited by cool ambient temperatures in higher altitudes. ere is fear that as the earth warms, these limits will shi enabling ourishing of these mosquitos, and Dengue fever in previously una ected areas. Furthermore, there is a possibility that as ambient temperatures rise, the lifecycle of the malaria parasite will accelerate, thereby increasing the rate of spread of malaria.22 Role of the physician e “pledge for planetary health to unite health professionals in the Anthropocene” encourages physicians to strive to upli our planet. Physicians should actively address environmental, social, and structural determinants of health andprotect the natural systems that support a viable planet for future generations. We should share and expand our knowledge for the bene t of society and the planet.23 Physicians caring for pregnant women should try to ensure that their patients have access to clean drinking water, shade and cooling centres during periods of extreme heat. Women should be informed about the riskof illness fromfood, water andvector-bornepathogens. All food must be prepared with safe clean water. Actions needed by the health-sector Health professionals, health associations, academics and researchers O&G Forum 2022; 32: 01-03 EDITORIAL OBSTETRICS & GYNAECOLOGY FORUM 2022 | ISSUE 3 | 2