Effect of Vitamin D Replacement on Maternal and Neonatal Outcomes

Hypovitaminosis D is prevalent worldwide across the lifecycle, including pregnant women, and particularly in the Middle East. It has been associated with adverse maternal and neonatal outcomes. While the Institute of Medicine (IOM) recommends 600 IU of vitamin D per day to reach a 25-Hydroxyvitamin D (25(OH)D) level ≥ 20 ng/ml, the Endocrine Society (ES) recommends 1,500-2,000 IU/day to reach a level ≥ 30 ng/ml, and the WHO guidelines do not recommend any supplementation as part of routine prenatal care. They do however underscore the fact that subjects with the lowest levels may be the ones to benefit most from vitamin D replacement. The benefits of such an approach and the doses needed to reach desirable levels have not been tested. This randomized trial proposes to do so, testing the effect of two vitamin D doses, a low dose of 600 IU daily and a high dose of 3,000 IU daily.

330 pregnant women, with 25(OH)D level 10-30 ng/ml during the early second trimester will be recruited form the American University of Beirut-Medical Center (AUB-MC), and Bahman Hospital. They will be randomized, in a double blinded fashion, to receive daily equivalent doses of cholecalciferol, 600 IU or 3,000 IU until delivery. Maternal clinical information and a food frequency questionnaire will be obtained at each visit until delivery. Maternal 25(OH)D and chemistries, including Calcium, creatinine, lipid profile, glucose and Insulin will be assessed at study entry, during third trimester and at delivery. Fetal measurements will be collected at study entry and during the second trimester. Neonatal anthropometric variables and venous umbilical cord 25(OH)D level will be measured at birth and infants will also undergo dual-energy x-ray absorptiometry (DEXA) scan assessment, for bone and fat mass, at one to 6 weeks. Maternal and neonatal genetic studies for vitamin D genes polymorphism, and other modules of placnetal calcium transport will be also performed.

Throughout the study, adverse events will be collected systematically and an independent Data and Safety Monitoring Board will be asked to review serious adverse events.

The percent of women achieving 25(OH)D ≥ 20ng/ml in the low dose will be compared to that in the high dose using Chi-Square. Independent t-test will be used to compare mean neonatal bone mineral content at one month of age between the 2 arms. For other outcomes, t-test will be used for continuous outcomes and Chi-square will be used for binary outcomes to compare means and proportions, respectively. The primary analysis is an intention-to-treat analysis (ITT) of unadjusted results. For the primary outcomes, p- values will be considered statistically significant if ≤ 0.025.

The investigators study would be the only randomized controlled trial in the Middle East, to investigate the recommended daily allowance for vitamin D, and the desirable dose to optimize neonatal musculoskeletal health, in women with low 25(OH)D levels, levels that are reflective of those in most countries from the Middle East.

Inclusion criteria

• Pregnant women gestational age (GA)< 14 weeks at screening visit. Middle Eastern woman (Middle East countries defined by WHO: Bahrain, Egypt, Iran, Iraq, Palestine, Jordan, Kuwait, Lebanon, Oman, Qatar, Saudi Arabia, Syria, , United Arab Emirates, Yemen)
• 25(OH)D level between 10ng/ml and 30ng/ml
• Age > 18 years
• Vitamin D supplementation ≤ 200 IU daily (If daily vitamin D supplementation > 200 IU daily, at enrollment, the pregnant women will be advised to adjust prenatal multivitamin doses in such a way that total vitamin D supplementation per week doesn't exceed 1400 IU per week, in consultation with primary Obstetric and Gynecology (OB-GYN) physician.)

Exclusion criteria

• 25(OH)D level < 10 ng/ml or > 30 ng/ml.
• Known metabolic bone disease
• Current medications likely to interfere with vitamin D metabolism (enzyme inducing anticonvulsants, anti -TB)
• Vitamin D supplementation > 600 IU daily
• Pregnant women with twins