The purpose of this study is to further investigate the association between vitamin D deficiency/insufficiency and hypertensive disorders of pregnancy by studying the impact of screening for vitamin D deficiency and supplementation when low levels of vitamin D are detected. Screening for vitamin D deficiency (less than 20 ng/mL) and insufficiency (less than 30 ng/mL) may determine the need for additional supplementation, as most prenatal vitamins only contain 400 IU of vitamin D. The rates of hypertensive disorders of pregnancy amongst patients who received supplementation and maintained adequate vitamin D levels will be followed.