Vitamin D Dynamics in Women
| Status: | Recruiting |
|---|---|
| Conditions: | Women's Studies |
| Therapuetic Areas: | Reproductive |
| Healthy: | No |
| Age Range: | 19 - 35 |
| Updated: | 9/2/2018 |
| Start Date: | July 2015 |
| End Date: | June 2019 |
| Contact: | Kimberly O. O'Brien, PhD |
| Email: | koo4@cornell.edu |
| Phone: | 607-255-3743 |
Vitamin D Dynamics in Pregnant Women and Non-Pregnant Women of Reproductive Age
The goal of this pilot project is to utilize stable isotopically labeled vitamin D3 and state
of the art mass spectrometric methodology to assess vitamin D dynamics during pregnancy in
relation to calcitropic hormone status at this key life stage. At the conclusion of this
study, the investigators will have obtained novel information on the absorption and
utilization of vitamin D in women and determined if maternal vitamin D3 or maternal 25(OH)D3,
or both, can be transferred across the placenta to the fetus. The long-term goal is to better
understand the unique metabolism of vitamin D during pregnancy.
of the art mass spectrometric methodology to assess vitamin D dynamics during pregnancy in
relation to calcitropic hormone status at this key life stage. At the conclusion of this
study, the investigators will have obtained novel information on the absorption and
utilization of vitamin D in women and determined if maternal vitamin D3 or maternal 25(OH)D3,
or both, can be transferred across the placenta to the fetus. The long-term goal is to better
understand the unique metabolism of vitamin D during pregnancy.
Nearly 30% of US women are either vitamin D insufficient or deficient. Vitamin D inadequacy
during gestation is increasingly linked to adverse birth outcomes including preterm birth,
the risk of cesarean section and placental and pregnancy-associated infections. At this time
the Institute of Medicine (IOM) has not advocated any increase in vitamin D intake across
gestation but this remains controversial in large part due to insufficient information on the
basic physiology of vitamin D. Pregnancy induces dramatic changes in regulation of vitamin D.
The investigators hypothesize that increased maternal, placental, and fetal vitamin D
requirements during late gestation will result in an increase in vitamin D absorption and a
decrease in the half-life of both vitamin D3 and 25-hydroxyvitamin D. The fetus is entirely
dependent on maternal vitamin D to meet its requirements for this nutrient. Maternal vitamin
D is thought to be passively transferred across the placenta to the fetus given that neonatal
concentrations of 25(OH)D are at least 20-30% lower than maternal 25(OH)D concentrations. To
date, much of what is known about vitamin D absorption and utilization in humans has been
extrapolated from early radiotracer studies in adult men and non-pregnant women and there are
no in vivo data to determine if maternal vitamin D3 or maternal 25(OH)D3, or both, can be
transferred across the placenta to the fetus
The specific aims of this project are to:
1. Obtain pilot data on the absorption of vitamin D3 in non-pregnant and pregnant women,
following oral dosing with deuterated vitamin D3
2. Obtain pilot data on the dynamics of the conversion of vitamin D3 into 25-hydroxyvitamin
D3, following dosing with oral deuterated vitamin D3
3. Estimate the serum half-life of vitamin D3 and 25-hydroxyvitamin D3 in non-pregnant and
pregnant women
4. Evaluate the absorption of vitamin D3 in late gestation and evaluate the concentrations
of these forms of vitamin D in the cord blood at birth
5. Evaluate the ability of the placenta to rapidly transfer maternally absorbed vitamin D3
to the fetus at term
6. Evaluate the ability of the placenta to rapidly transfer maternally absorbed 25(OH)D3 to
the fetus at term
during gestation is increasingly linked to adverse birth outcomes including preterm birth,
the risk of cesarean section and placental and pregnancy-associated infections. At this time
the Institute of Medicine (IOM) has not advocated any increase in vitamin D intake across
gestation but this remains controversial in large part due to insufficient information on the
basic physiology of vitamin D. Pregnancy induces dramatic changes in regulation of vitamin D.
The investigators hypothesize that increased maternal, placental, and fetal vitamin D
requirements during late gestation will result in an increase in vitamin D absorption and a
decrease in the half-life of both vitamin D3 and 25-hydroxyvitamin D. The fetus is entirely
dependent on maternal vitamin D to meet its requirements for this nutrient. Maternal vitamin
D is thought to be passively transferred across the placenta to the fetus given that neonatal
concentrations of 25(OH)D are at least 20-30% lower than maternal 25(OH)D concentrations. To
date, much of what is known about vitamin D absorption and utilization in humans has been
extrapolated from early radiotracer studies in adult men and non-pregnant women and there are
no in vivo data to determine if maternal vitamin D3 or maternal 25(OH)D3, or both, can be
transferred across the placenta to the fetus
The specific aims of this project are to:
1. Obtain pilot data on the absorption of vitamin D3 in non-pregnant and pregnant women,
following oral dosing with deuterated vitamin D3
2. Obtain pilot data on the dynamics of the conversion of vitamin D3 into 25-hydroxyvitamin
D3, following dosing with oral deuterated vitamin D3
3. Estimate the serum half-life of vitamin D3 and 25-hydroxyvitamin D3 in non-pregnant and
pregnant women
4. Evaluate the absorption of vitamin D3 in late gestation and evaluate the concentrations
of these forms of vitamin D in the cord blood at birth
5. Evaluate the ability of the placenta to rapidly transfer maternally absorbed vitamin D3
to the fetus at term
6. Evaluate the ability of the placenta to rapidly transfer maternally absorbed 25(OH)D3 to
the fetus at term
Inclusion Criteria (Non-pregnant and pregnant participants participants):
- Caucasian race
- Age 19-35
- Body mass index (BMI) or pre-pregnancy BMI (If currently pregnant) < 28 kg/m2
Inclusion Criteria (Additional criteria for pregnant participants):
- Singleton pregnancy
- 20 to <36 weeks pregnant during study participation
- No pregnancy complications
- Planning to delivery by scheduled c-section (if participating in the placental
transfer study Aims 4-6)
Exclusion Criteria (Non-pregnant and pregnant participants):
- BMI or pre-pregnancy BMI ≥ 28 kg/m2
- Human immunodeficiency virus (HIV) infection
- Diagnosed eating disorder
- Malabsorption disease
- Diabetes
- Elevated diastolic blood pressure (>110 mm/Hg)
- Steroid use
- Substance abuse history
- Current use of medications known to influence vitamin D or calcium homeostasis
- Plans to travel to lower latitude during the 20-day study period
- Plans to become pregnant during the study period (non-pregnant only)
- Refuses to discontinue tanning bed use during study period
- Refuses to discontinue vitamin or mineral supplement use during study period
(non-pregnant only)
Exclusion Criteria (Additional criteria for pregnant participants):
- Gestational diabetes
- Pregnancy hypertension
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