|Year : 2014 | Volume
| Issue : 2 | Page : 89-92
Pregnancy and Vitamin D
Jitendra Ingole1, Sonali Ingole2
1 Department of Internal Medicine, Smt. Kashibai Navale Medical College, Pune, Maharashtra, India
2 Department of Obst & Gynecology, Smt. Kashibai Navale Medical College, Pune, Maharashtra, India
|Date of Web Publication||11-Aug-2014|
Smt. Kashibai Navale Medical College, Pune, Maharashtra
Source of Support: None, Conflict of Interest: None
Vitamin D insufficiency is common in women across different races of childbearing age. It is being increasingly discovered that vitamin D has many important bodily functions apart from skeletal actions pertaining to Calcium homeostasis. Evidence suggests that the maternal risks due to vitamin D deficiency includes eclampsia, increased risk of gestational diabetes mellitus, glucose intolerance; and fetal risks include risk of rickets, osteoporotic fracture in late adulthood. It may be prudent to include screening of all pregnant women for vitamin D level as a part of routine antenatal care and supplementation be given if found deficient.
Keywords: Maternal and fetal health, pregnancy, vitamin D
|How to cite this article:|
Ingole J, Ingole S. Pregnancy and Vitamin D. J Mahatma Gandhi Inst Med Sci 2014;19:89-92
| Introduction|| |
The role of vitamin D during pregnancy and its effect on maternal and fetal health is just beginning to be understood. In the last 5 years, there has been an explosion of published data concerning the immune effects of vitamin D, yet little is known in this regard about the specific immune effects of vitamin D during the pregnancy period. What is clear, however, is that vitamin D deficiency during pregnancy is rampant throughout the world. ,,
| Epidemiology|| |
From early 1980s, when the laboratory test for serum vitamin D level began available, there was surge in diagnosis of vitamin D deficiency. It also became clear in subsequent years to come, that persons having dark skin pigmentation and having less exposure to Sun were amongst majority in deficient group. 
But what came as a surprise was high incidence of vitamin D deficiency, even in fair skinned people. The prevalence of vitamin D deficiency is thus, widespread equally in developing as well as developed countries. Its presence in pregnant women, carries a special importance due to possible chance of affecting fetus. It may be worthwhile to note that a few years ago, a 14-year-boy lead campaign to Scottish parliament for special importance of vitamin D awareness and recommendation in antenatal care (ANC) program in Scotland. 
Although, it is difficult to predict exact figures of pregnant females with vitamin D deficiency in developing countries due to lack of proper data; but nonetheless the condition is also common in India and needs urgent insight on broader level.  If certain disorders can be prevented by supplementing with an essential vitamin, it definitely will go a long way toward promotion of better health for expectant mothers and their off springs. Canadian Pediatric Society, in 2007, therefore recommended 2000 IU of vitamin D 3 for pregnant and lactating mothers with periodic blood tests to check levels of 25-hydroxy vitamin D (25(OH)D) and calcium. ,
| Risk Factors for Vitamin D Deficiency|| |
The following are postulated as risk factors for causation of vitamin D deficiency in pregnancy: Lack of sunlight exposure, fat malabsorption, vegetarian diet, drug therapy (steroids, anti-epileptic drugs), deeply pigmented skin and obesity. ,
Why vitamin D deficiency is important in relation to pregnancy?
Vitamin D deficiency can be linked to maternal and fetal effects. Maternal effect postulated to be due to the deficiency are: Eclampsia,  insulin resistance  and increased risk of gestational diabetes mellitus. 
Fetal effects of vitamin D deficiency are plenty some being short term and others may become apparent in later life. The skeletal role of vitamin D deficiency (in causation of rickets) is well-documented. With severe maternal vitamin D deficiency, the fetus rarely may develop rickets in utero with manifestation at birth.  Throughout gestation, if a woman is vitamin D deficient, it appears to impact fetal bone health more than maternal.  Vitamin D status during pregnancy also does play a role to certain extent in fetal skeletal development, tooth enamel formation and general fetal growth and development. 
Further, cardiovascular risk factors may have origin in fetal vitamin D deficiency.  It has also been shown conclusively that cord blood vitamin D level have strong correlation with innate immune response of fetus. 
How common is vitamin D deficiency in pregnant women
One recent study highlights the need of vitamin D in pregnancy. Hamilton et al.  presented findings in a study conducted on 559 pregnant women in year 2010. Serum sample for vitamin D level (25(OH) vitamin D3) was collected during routine ANC visits by pregnant women. The study revealed widespread vitamin D deficiency across different races African American (48%), hispanic (38%), caucasian/other (14%). 
Another study by Javaid et al.  concluded that maternal vitamin D insufficiency is common during pregnancy and is associated with reduced bone-mineral accrual in the offspring during childhood.
| Diagnosis|| |
Vitamin D deficiency should be suspected in a pregnant woman having low exposure to Sunlight, vegetarian dietary habits. Other clinical symptoms such as joint pain(s) may be non-specific. Thus, estimation of vitamin D level by laboratory remains the accurate way of assessing the deficiency and its severity. 
The correct test to order for is serum 25(OH) vitamin D test. It may be noted, that another test vitamin D, 1,25 dihydroxy does not reflect true status of vitamin D deficiency. Studies have shown that the vitamin D, 1,25 dihydroxy level does not significantly change until 25(OH) vitamin D, drops to levels that are considered severe vitamin D deficiency. 
There seems to be a lot of conflicting reports about adequate level of vitamin D.  However many experts accept a range 75 nmol/L (≥30 ng/mL) as optimal. Further, controversy also exists regarding the optimum concentration of vitamin D in pregnancy. Most experts, though, agree that serum vitamin D levels below 50 nmol/L (20 ng/mL) represent deficiency. , However, this current practice is based on the skeletal actions of the vitamin and it is yet not clear whether the same values of vitamin D Level are for applicable for pregnancy or not.
| Therapy|| |
Currently, women of reproductive age are assumed to be able to obtain the recommended intake for vitamins and no national organization recommends routine vitamin D supplementation during the pregnancy period. The US Preventive Services Task Force does not comment for or against routine screening for vitamin D deficiency in pregnant women.  Further, there is a lot of information and misinformation about vitamin D and suggestions about timing, dose, route of vitamin D supplementation.
But now, given the fact that vitamin D deficiency is much more common , than thought of, pharmacotherapy remains the practical and feasible option for correcting vitamin D levels. There are wide differences of thoughts over what should be the recommended dose for vitamin D. An important point to note here is that vitamin D deficient patients do require higher doses than recommended for prophylaxis against vitamin D deficiency. Recently, Institute of Medicine (USA) suggested that adequate dose for vitamin D needs to be 2000 to maximum 4000 IU/day. Whilst this may appear as very large dose, but there are no known teratogenic effects until date found to be due to vitamin D supplementation.
In yet another study, wherein supplementation of oral cholecalciferol in a 10 day course of 50,000 IU (Total dose 5 Lac IU), did not cause toxicity such as hypercalcemia.  suggesting that concern of vitamin D toxicity is probably much feared than actually found in clinical practice.
A recent randomized controlled trial with 350 women of diverse racial and ethnic backgrounds showed that 4000 IU vitamin D/day is most effective in improving the vitamin D status of pregnant women, attaining circulating levels of at least 40 ng/mL (100 nmol/L) for 25(OH)D. 
Vitamin D supplementation during lactation
Human milk contains little vitamin D (approximately 20 IU/L) and women who are vitamin D-deficient provide even less to their breastfed infants,  Lactating women given 4000 IU of vitamin D3/day not only had an increase in the level of 25(OH)D to more than 30 ng/mL but were also able to transfer enough vitamin D3 into their milk to satisfy an infant's requirement.
The vitamin is available as ergocalciferol (also called vitamin D2); and cholecalciferol (vitamin D3 activated form). Cholecalciferol (vitamin D3) is preferred over ergocalciferol for replenishment.
Cholecalciferol is available in oral form sachet containing 60,000 international units (IU); Tablets containing 1000 IU; or Injection form (aqueous solution vitamin D3 of strength 6 Lac IU). For routine supplementation for pregnant women, sachet containing 60,000 IU of vitamin D3 may be used with added advantage of being non-invasive route of administration.
Should vitamin D be incorporated in national level maternal and child health care program
Serum level of vitamin D may be measured as routine before planning for pregnancy/during antenatal visit check-up. And if found deficient vitamin D may be given as short course supplementation (Sachets form) during routine follow-up visits of pregnant woman. As the vitamin is fat soluble, short course supplementation may also suffice purpose and also improving patient compliance.
| Areas of Uncertainty|| |
Whilst majority of trials carried until recently were highlighting importance of vitamin D in bone and mineral metabolism, the non-skeletal effects such as effect on pregnancy, fetus are getting discovered. Thus, effects of supplementation for skeletal benefit versus non skeletal benefit also remains an area of research. , Whether it is vitamin D alone which is responsible for important functions during pregnancy or whether it is complex interplay between genetics, epigenetics and some other factors? Would supplementation of vitamin D carry equal benefits amongst all given pregnant women? What if vitamin D deficiency is detected late in pregnancy Would supplementation will still be of any value in such case? These questions still remain elusive until date.
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