Impact of Maternal Body Weight on Vitamin D Status During Pregnancy

University of Ulster240 enrolled

Overview

Research shows high levels of vitamin D deficiency in pregnant women in Northern Ireland. Body composition is a determinant of vitamin D status. Vitamin D is a fat soluble vitamin and therefore may be hidden within the adipose/fat tissue in overweight/obese individuals. All pregnant and breastfeeding women are advised to take a daily supplement containing 10μg vitamin D. The investigators hypothesise that overweight/ obese pregnant women have a lower vitamin D status than their leaner counterparts at the start of pregnancy and may need a higher daily supplementation to achieve a sufficient status. The investigators propose a randomised supplementation study where pregnant women (n 240) from the Western Health and Social Care Trust Area will be invited to take part. Inclusion criteria: pregnant women first trimester, without current pregnancy related complications, singleton pregnancy, aged ≥18 years, with Body Mass Index (BMI) \> 18.5kg /m². Participants will be randomised to receive either 0μg (placebo) plus a multivitamin or 10μg vitamin D plus a multivitamin from 12 weeks gestation until delivery. The multivitamin already contains 10μg vitamin D; Therefore participants will be randomised to receive a total of 10μg or 20μg vitamin D. Blood samples (20mls) will be taken at 12, 28 and 36 weeks gestation. A sample of blood will be taken from the cord after delivery. Vitamin D status is the main outcome measurement. All blood samples will be analysed for vitamin D and other associated metabolites. Data will be collected on health and lifestyle, supplementation use and food intake. Body composition measurements will be recorded at each appointment and infant anthropometric measurements will be taken from the maternal notes after delivery. Findings from this research will be used to inform nutrition policy on appropriate vitamin D supplementation levels in pregnancy which may be dependent upon pre pregnancy BMI.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

DOUBLE

Eligibility

Sex: FEMALEMin age: 18 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * Pregnant women * Age ≥18years * BMI \>18.5 kg/m² * Without current pregnancy related complications * At least 12 weeks gestation * Have a singleton pregnancy (as confirmed at first scan) * Pregnant women who are currently taking vitamin D and have had a sun holiday will be included in this study. All participants will agree to discontinue any current supplementation and will be provided with a multivitamin for the duration of pregnancy. Exclusion Criteria: * Aged \<18 years * Pregnancy BMI \<18.5kg/m² * Participants with multiple pregnancy * Participants currently involved in another research study * Participants with a history of gastrointestinal, hepatic, renal, vascular or haematological disorders. * Participants who have had in vitro fertilisation (IVF) treatment * Participants with a history of NTD affected pregnancies * Pregnant women with active thyroid disease (e.g., Graves, Hashimoto or thyroiditis) * Planned home births

Outcomes

Primary Outcomes

Change in Vitamin D (25-hydroxyvitamin D) status

Serum Vitamin D status (Week 12, 28 + 36 gestation) \& cord serum Vitamin D status (delivery)

Time frame: Baseline (Week 12 gestation), Mid-point (Week 28 gestation) & End of pregnancy (Week 36 gestation + Delivery)

Secondary Outcomes

Gestational weight gain

Time frame: Baseline (Week 12 gestation), Mid-point (Week 28 gestation) & End of pregnancy (Week 36 gestation)

Change in inflammation status

Plasma inflammation status (Week 12, 28 + 36 gestation) \& cord plasma inflammation status (delivery)

Time frame: Baseline (Week 12 gestation), Mid-point (Week 28 gestation) & End of pregnancy (Week 36 gestation + Delivery)

Change in bone turnover markers

Plasma bone turnover markers (Week 12, 28 + 36 gestation) \& cord plasma bone turnover markers (delivery)

Time frame: Baseline (Week 12 gestation), Mid-point (Week 28 gestation) & End of pregnancy (Week 36 gestation + Delivery)

Genetics

e.g. CYP2R1, CYP27B1, CYP24A1

Time frame: Baseline (Week 12 gestation)

Dietary intake

Food diary with food frequency questionnaire

Time frame: Week 28 gestation

Foetal growth chart measurement

Time frame: Baseline (Week 12 gestation), Mid-point (Week 28 gestation) & End of pregnancy (Week 36 gestation + Delivery)

Change in Vitamin D related measures

Blood Vitamin D related status (Week 12, 28 + 36 gestation) \& cord Vitamin D related status (delivery)

Time frame: Baseline (Week 12 gestation), Mid-point (Week 28 gestation) & End of pregnancy (Week 36 gestation + Delivery)

Haemoglobin

As part of full blood count

Time frame: Baseline (Week 12 gestation), Mid-point (Week 28 gestation) & End of pregnancy (Week 36 gestation + Delivery)

Plasma ferritin

Clinical chemistry analyser

Time frame: Baseline (Week 12 gestation), Mid-point (Week 28 gestation) & End of pregnancy (Week 36 gestation + Delivery)

Transferrin saturation

Clinical chemistry analyser

Time frame: Baseline (Week 12 gestation), Mid-point (Week 28 gestation) & End of pregnancy (Week 36 gestation + Delivery)

Iron status

Serum, clinical chemistry analyser

Time frame: Baseline (Week 12 gestation), Mid-point (Week 28 gestation) & End of pregnancy (Week 36 gestation + Delivery)

Soluble transferrin receptor

ELISA

Time frame: Baseline (Week 12 gestation), Mid-point (Week 28 gestation) & End of pregnancy (Week 36 gestation + Delivery)

Hepcidion

ELISA

Time frame: Baseline (Week 12 gestation), Mid-point (Week 28 gestation) & End of pregnancy (Week 36 gestation + Delivery)

Methylation analysis

Iron and vitamin D related genes

Time frame: Baseline (Week 12 gestation), Mid-point (Week 28 gestation) & End of pregnancy (Week 36 gestation + Delivery)

Impact of Maternal Body Weight on Vitamin D Status During Pregnancy

Overview

Conditions

Interventions

Eligibility

Locations (1)

Outcomes

Primary Outcomes

Secondary Outcomes