Vitamin D Supplementarion in Pregnant Women at Risk and COVID-19 (D-WOMAN)

Randomised Clinical Trial of Vitamin D Supplementation in Pregnant Women and Prevalence of Covid-19 Immunity.

Vitamin D defiency during pregnancy is a major public health problem worldwide; In Spain, the average intake of vitamin D is lower than recommendations in an elevated percentage of the population, ranging from 50 to 95%, according to the Spanish Society of Community Nutrition (SENC). Recent research suggests that adverse pregnancy outcomes are associated to vitain D deficiency. Associated comorbidities are further complicated by the SARS-COV-2 Pandemic. Few studies have assessed the transmission of SARS-CoV-2 antibodies from mothers who have had the disease or have been vaccinated to their newborns, either at birth or during breastfeeding, or how vitamin D concentration influences the generation of such an immune response. The COVID-19 pandemic is a dynamic situation. Peer-reviewed studies in large study cohorts point to a clear relationship between prevalence and severity of COVID-19 and vitamin D deficiency.

Researchers propose a randomized, non-blinded clinical trial in pregnant women recruited at the obstetrics and gynecology service of the Virgen de las Nieves University Hospital Granada during the appointment of the first gynecological control visit (weeks 10-16 of pregnancy). The woman participating in the study will be assigned to two randomized follow-up groups, intervention group that will be supplied with 1.000 IU of vitamin D and control group with 400 IU of vitamin D.All pregnant women who want to participate in the study but do not wish to supplement, will be part of another group, the unsupplemented control group. Participants will take the supplementation from 10-16 weeks of gestation to delivery. The frequency of gybecological visits will coincide with their routine prenatal visits: weeks 10-16, weeks 20-24 and weeks 34-36 of gestation. During the entire duration of the study, pregnant women will be in touch with the health professionals through routine hospital controls. The present study was approved by the Ethics Commitee CEIM/CEI of Granada, Spain.

Intervention group will be administered 1,000 UI of vitamin D and a control group will be administered 400 UI of vitamin D. Participants will take the supplementation from the enrollment to delivery.

The research group aims at evaluating the efficacy of vitamin D supplementation at modying maternal levels of serum 25-hydroxyvitamin D during pregnancy. Concentrations < 30 ng/ml shall be considered as low vitamin D concentration.

All deliveries that take place at less than 37 weeks' gestation are considered preterm deliveries. Cases of preterm birth will be evaluated in both groups of study respect to maternal vitamin D results.

The existence of a diagnosis of pre-eclampsia during pregnancy, defined following the ISSHP recommendations will be evaluated in both groups of study. This diagnosis will be obtained from a review of the patient's clinical history and will be assessed with respect to maternal vitamin D results.

The existence of a diagnosis of Gestational diabetes mellitus defined based on criteria from the American Diabetes Association will be evaluated in both groups of study.This diagnosis will be obtained from a review of the patient's clinical history and will be assessed with respect to maternal vitamin D results.

The prevalence of covid-19 and immunity to covid in the population will be calculated by the derivation of clinical blood test results for covid-19 antibodies (IGG, IGM).

Cases of miscarriage, fetal death and stillbirths in the groups of study will be assessed with respect to maternal vitamin D results.

A blood sample (IGG,IGM) will be taken from the neonate to determine the immunity against covid-19. Blood IGG results higher than 33.8 BAU/ml will mean positive for covid-19 immunity.

All newborns born weighing less than 2,500 gr shall be considered as small-for-gestational-age (based on specific population percentiles) will be assessed with respect to maternal vitamin D results.

The psychomotor development of the newborn will be assessed using a validated questionnaire called Brunet-Lézine. This questionnaire will be answered by the mothers during the 6 months of the newborn's life.

INCLUSION CRITERIA: Pregnant women Over 18 years of age. Attendance at the hospital complex and intending to give birth in public centres in the province of Granada. With the capacity to understand and sign the informed consent form. EXCLUSION CRITERIA: Consumers of vitamin complexes. Co-infection with other infectious viruses or bacteria (HCV, HBV, HIV, among others). Severe respiratory symptoms that prevent participation in the study.