Boon Lim1,2, Associate Professor
Department of Obstetrics and Gynaecology, Canberra Health Services,
Canberra, Australia
Australian National University
As the impacts of climate change continue to accelerate, there has been
an exponential rise in the number of natural disasters, with flooding
playing a significant role. Over the last 50 years there has been a
five-fold increase in the number of floods, with flooding contributing
to 44% of all natural disasters (World Meteorological Organisation.Weather-related disasters increase over past 50 years, causing
more damage but fewer deaths , 2021). Developing countries are
particularly vulnerable to the effects of these natural disasters, which
contribute to direct health implications as well as significant
disruptions to access to health care. Data surrounding the impacts of
climate change on health outcomes has grown, revealing a growing field
of literature examining the negative impacts of flooding on reproductive
outcomes.
Multiple direct and indirect factors contribute to poor reproductive
health outcomes following flooding events. Flood waters lead to poor
water quality as well as an increase in infectious diseases.
Displacement of large numbers of people, particularly in developing
countries, leads to overcrowding in emergency accommodation and
subsequently increased rates of communicable diseases. Furthermore,
damage to health infrastructure and limited access to health facilities
impact women’s ability to seek pregnancy care (UK AID. Foreign,
Commonwealth and Development Office. The effects of floods on
access to sexual and reproductive health and family planning in
Pakistan , 2023). The physical and psychological stressors experienced
by women affected by floods are hypothesised to contribute to the higher
rates of gestational hypertension, preeclampsia and babies with low
birth weights (Partash et al. Taiwan J Obstet Gynecol 2022;
61:10-4). These effects are compounded in lower socioeconomic areas,
particularly developing countries with already limited resources.
Following recent floods in Pakistan, over 8 million people were
displaced; only 29% of women in displacement camps have received
counselling on pregnancy care and 19% have received delivery kits (UK
AID, 2023).
There have also been studies evaluating the influence of environmental
factors on the sex ratio (the ratio of males to females in a population)
of live births. Anaesthetic gases, air pollution and times of flooding
have all been shown to impact sex ratio of deliveries in affected
populations. Following floods in Brisbane, Australia there was a
noticeable reduction in the sex ratio, thought to be linked to a
reduction of the hardness and pH in the drinking water. The change in
sex ratio is hypothesised to be due to the sensitivity of the Y-bearing
spermatozoa to dietary changes during the meiotic stages of
spermatogenesis, which occurs approximately 7 weeks prior to arrival of
the ejaculate (Lyster & Bishop. J. Reprod. Fertil,
1965;10:35-47). This effect of flooding is further supported by the
seasonal trend noted in the sex ratio, which is related to the level of
precipitation approximately 10-11 months prior to birth (Lyster.BJOG , 1974;81:626-631) (Fig.1).
With flooding becoming increasingly prevalent throughout the world, it
is clear that the focus needs to shift to providing affected communities
by reducing barriers to accessing care, particularly antenatal care.
Careful planning is required to ensure improved access to care, water
quality and reduce overcrowding to reduce pregnancy complications and
better health outcomes of children globally.
Figure 1.