The researchers note that the VDDs within the studied pregnant women to be 77.7% during the quarantine period, with the strict lockdown found to be the only influencing factor on such deficiencies following a reduced sunlight exposure.
The Spanish researchers emphasise: “As far as we know, this research is the first to explore the changes in 25(OH)D levels in pregnant women due to confinement related to the COVID-19 pandemic.”
“This valuable information could guide us in the future to take action, such as with vitamin D supplementation, in the case that public officials order the population to stay indoors for any given reason,” they stress, highlighting the importance of establishing supplementation and dietary intervention strategies within such at-risk groups.
Nutrition for pregnancy
Vitamin D is an essential nutrient required for many bodily functions, with an optimal status associated with an array of health benefits spanning from cardiovascular function to immunity. Exposure to UVB sunlight exposure is the main source of the vitamin, yet, inevitably there are variations in its availability according to variables such as latitude, season, and time of the day. Following this, it has been established that significant variations in its absorption occur across different regions and populations, as well as significant deficiencies.
It is noted that optimal vitamin D levels are even more vital throughout pregnancy, due to correlations between deficiencies and adverse outcomes, such as preterm birth, pre-eclampsia and gestational diabetes mellitus (GDM). However, a strong prevalence of deficiencies in this population has been found, with no specific guidelines for supplementation implemented.
The long-term outcomes following the Covid-19 epidemic, in relation to eating behaviours and physical activity, have been recently investigated due to the significant restrictions limiting sunlight exposure to the population. A previous cross-sectional study conducted by the researchers explored VDDs in pregnant women and its association with gestational diabetes. Yet, a strict lockdown was imposed in this area of Spain during the study.
To continue this research and assess the impact of the strict lockdown imposed in the region, the scientists conducted a further retrospective study to establish the potential relationship between VDD in pregnant women and the occurrence of lockdown.
Throughout this initial study period of 2019 to 2020, 886 pregnant women were recruited. Over the 10-month period, blood samples were collected during the second trimester to obtain serum 25(OH)D concentrations, in addition to a gestational diabetes screening test.
The data was analysed using a logistic regression model and was adjusted by biweekly measured vitamin D-specific UVB dose in the studied geographical area, establishing a prevalence odds ratio (POR) for the association.
Following this, it was established that the POR during the strict lockdown was 4.0, with a significant deficiency prevalence of 77.5% during quarantine.
In addition, the logistic regression model established that in the pregnant women, VDD prevalence was significantly influenced by the strict lockdown compared to other external factors.
The study concludes: “This VDD prevalence was greatly influenced by the quarantine, with a significant increase in the SL group (77.8%), as a consequence of the decreased exposure to sunlight due to the in-house confinement in this cohort of participants.”
Considering the significant adversities resulting from VDDs during pregnancy for the health of both mother and child, they add: “In addition to skin production, vitamin D-enriched diets and supplementation are also relevant sources of vitamin D. Access to food and medication was not significantly restricted during home confinement, and no special measures were taken to supplement the participants.”
However, it should be noted that longer term studies utilising higher levels of control are required, as well as within a sample more representative of different regions, to enable for the implementation of potential dietary interventions.
“Influence of Strict Lockdown on Vitamin D Deficiency in Pregnant Women: A Word of Caution”
by Nuria Agüero-Domenech, Eduardo Bernabeu, Antonio García-Valentín, Ana Sarrión, Silvia Jover, Javier Baranda, Ernesto Cortés-Castell, Vicente Gil-Guillén and María J. García-Terue