Please select the eligibility criteria that correspond to the clinical trial below.
Title: Calcium Plus Vitamin D Supplementation During Pregnancy of Adolescent Mothers: Effects on Maternal and Infant Bone Mass, Calcium and Bone Metabolism and Breast Milk Composition
Brief Summary: Pregnancy and lactation are periods of high calcium requirement. Inadequate maternal calcium intake and vitamin D insufficiency may adversely affect fetal and neonatal growth and maternal bone mass particularly in adolescent mothers. The investigators propose to evaluate the influence of calcium plus vitamin D supplementation during pregnancy on bone mass of lactating adolescent mothers with habitually low calcium and vitamin D, on fetal growth and neonate bone mass. Mothers are randomly assigned to receive daily calcium (600 mg) plus vitamin D3 (200 IU) supplement or placebo from mid gestation until parturition. Fetal growth parameters are assessed by standard ultrasound techniques at mid and late gestation. Maternal bone mass is assessed by dual energy x-ray absorptiometry (DXA) at 2 and 5 months postpartum and 6 months after weaning. Infant bone mass is assessed by DXA at 2 months postpartum.


Options:
A: Inclusion Criteria:

* Healthy pregnant Caucasian women aged 24-41 years,
* A normal pregnancy giving birth between 38-42 gestational weeks.

Exclusion Criteria:

* Chronic diseases,
* Other ethnic origin than Caucasian, and
* Alcohol or drug abuse.
B: Inclusion criteria:

1. 28 0/7-36 6/7 weeks gestational age (GA) at birth;
2. family identifies the child as black or African American;
3. \< 28 days of supplemental oxygen (subsequent oxygen therapy for \< 72 hrs for a brief subsequent illness or surgery will be allowed);
4. admitted to a participating site NICU, special care nursery, transitional care nursery, or well-baby nursery as a neonate; and
5. \< 40 weeks corrected GA at enrollment.

Exclusion criteria:

1. BPD (\> 28 days of supplemental oxygen);
2. pre-existing diagnosis of moderate to severe osteopenia of prematurity and/or alkaline phosphatase \> 700;
3. history of fracture;
4. gastrointestinal surgery, including for NEC;
5. known gastrointestinal malabsorption;
6. major congenital anomaly;
7. congenital pulmonary or airway disorder (e.g., cystic fibrosis, tracheomalacia, swallowing disorder, bronchopulmonary sequestration);
8. documented wheezing or stridor prior to enrollment;
9. previous vit. D supplementation with \> 400 IU/day;
10. family plans to move more than 60 miles from CWRU or other pre-defined radius at other sites;
11. baseline hypo- or hypercalcemia, hypo- or hyperphosphatemia; and
12. baseline 25(OH) D level \< 10 ng/ml.
C: Inclusion Criteria:

* Healthy, singleton term infants of appropriate for gestational age, according to Centers for Disease Control (CDC) growth charts based on weight at birth between 5th and 95th percentiles for sex
* Born to healthy breastfeeding women
* Exclusively breast fed infants from birth, according to WHO definition: breast milk, expressed breast milk, vitamins, minerals and medicine but not including water, breast milk substitutes, other liquids and solid foods.

Exclusion Criteria:

* Infants of mothers with a history of gestational diabetes or hypertension in pregnancy; chronic alcohol use; malabsorption syndromes (Celiac disease, Crohn's, etc.), due to malabsorption of fat soluble vitamins
* Mothers taking any medications that can affect vitamin D metabolism (anticonvulsants and corticosteroids)
* Mothers taking ≥ 2,000 IU/d of vitamin D from supplementation
D: Inclusion Criteria:

* 13-19 y old
* between 23 and 29 wk of gestation
* primiparous
* carrying single fetus
* intending to exclusively or predominantly breastfeed

Exclusion Criteria:

* chronic health problems
* smokers
* users of nutritional supplements, except iron supplements provided during standard prenatal care

Answer: D