http://informahealthcare.com/jmf ISSN: 1476-7058 (print), 1476-4954 (electronic) J Matern Fetal Neonatal Med, Early Online: 1–5 ! 2015 Taylor & Francis. DOI: 10.3109/14767058.2015.1064106
ORIGINAL ARTICLE
Comparison of cord blood vitamin D levels in newborns of vitamin D supplemented and unsupplemented pregnant women: a prospective, comparative study J Matern Fetal Neonatal Med Downloaded from informahealthcare.com by RMIT University on 08/20/15 For personal use only.
Rajesh Nandal1, Rajiv Chhabra1, Deepak Sharma2, Meenakshi Lallar3, Urvashi Rathee4, and Prabhat Maheshwari1 1
Department of Pediatrics, Artemis Health Institute, Gurgaon, Haryana, India, 2Department of Neonatology, Fernandez Hospital, Hyderguda, Hyderabad, Andhra Pradesh, India, 3Department of Obstetrics and Gynecology, SHKM Medical College Mewat, Haryana, India, and 4Department of Obstetrics and Gynecology, Artemis Health Institute, Gurgaon, Haryana, India Abstract
Keywords
Objective: To screen pregnant women for deficiency of 25-hydroxyvitamin D (25(OH)D) and supplement selected vitamin D deficient pregnant women with vitamin D and to compare 25(OH)D levels in cord blood between them. Method: Sixty pregnant women were selected as cases (vitamin D levels 530 ng/ml) and 60 unscreened pregnant women were taken as controls. Cases were supplemented with available 60 000 IU vitamin D every two weeks for eight doses or till delivery, whichever was earlier. In both the cases and controls, cord blood was collected at the time of delivery and tested for 25(OH)D levels using Biomerieux miniVIDAS. Result: Maximum (66.7%) pregnant women who received vitamin D supplementation had cord blood vitamin D level 430 ng/ml, while only 3.3% unsupplemented pregnant women had cord blood vitamin D level 430 ng/ml. The median cord blood vitamin D level was 36.5 ng/ml in vitamin D supplemented and 11.35 ng/ml in unsupplemented women. The mean birth weight and mean crown heel length were 3.1 ± 0.485 kg versus 2.8 ± 0.705 kg and 49.35 ± 1.36 cm versus 48.67 ± 2.12 cm, respectively. Conclusion: Vitamin D supplemented women had sufficient levels of 25(OH)D in cord blood at birth in maximum cases and neonates had higher birth weights and increased crown heel length.
Birth weight, cord blood, crown heel length, 25(OD)D, pregnancy, supplementation, vitamin D
Introduction Vitamin D has a pivotal role in immediate and long-lasting health of the offspring. High prevalence of vitamin D deficiency during pregnancy and resurgence of rickets in infants and toddlers is being increasingly recognized worldwide [1]. The two major forms of vitamin D are vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). Vitamin D2 is obtained from plant sources. Vitamin D3 is mainly obtained in diet from animal sources and it is also synthesized in skin from exposure to UV-B radiation. Less than 10% of vitamin D comes from dietary sources in the absence of food fortification or the use of supplements. Vitamin D deficiency during pregnancy and subsequently in newborns has been observed in studies worldwide. Although vitamin D supplementation during pregnancy is effective in correcting vitamin D deficiency but there is no consensus with regard to dose
Address for correspondence: Dr. Deepak sharma, Department of Neonatology, Fernandez Hospital, Hyderguda, Hyderabad, Andhra Pradesh, India. E-mail: [email protected]
History Received 17 April 2015 Revised 4 June 2015 Accepted 16 June 2015 Published online 18 August 2015
and frequency of vitamin D supplementation during pregnancy. Researchers across the globe have studied vitamin D supplementation during pregnancy in different doses as vitamin D levels and requirements vary with sun exposure, skin color, nutrition, etc., which in turn lead to variable requirements of vitamin D in different populations. Taking into account high prevalence of vitamin D deficiency among pregnant women and their newborns in India and a vital role of vitamin D in neonatal, infant and child health this study was undertaken. The aim of this study was to screen pregnant women for vitamin D deficiency and supplement vitamin D in deficient pregnant women and then compare 25-hydroxyvitamin D (25(OH)D) levels in the cord blood of vitamin D supplemented deficient pregnant women and unsupplemented unscreened pregnant women.
Material and methods The present study was a prospective comparative study conducted during the period November 2013 to May 2014 in a tertiary care hospital in urban Gurgaon. The pregnant women included in the study belonged to upper socioeconomic class. The study was in agreement with the hospital ethics
2
R. Nandal et al.
J Matern Fetal Neonatal Med, Early Online: 1–5
Table 1. The classification of vitamin D levels given by Endocrine Society.
Table 2. Vitamin D levels of pregnant women in the case group. Cases (n ¼ 60)
Level
J Matern Fetal Neonatal Med Downloaded from informahealthcare.com by RMIT University on 08/20/15 For personal use only.
Deficient Insufficient Sufficient Potential toxicity
Range (ng/ml)
Range (nmol/ml)
520 20–29 30–100 4100
550 50–72.5 75–250 4250
committee and human rights committee. Two groups were formed, 60 cases (64 pregnant women were screened by determination of 25(OH)D level at 20 ± 2 weeks of gestation out of which 60 women were found deficient with vitamin D levels 530 ng/ml on screening and were included as cases). Sixty unscreened pregnant women were taken as controls. Pregnant women with multiple pregnancy, chronic renal diseases, atherosclerosis, sarcoidosis, histoplasmosis, hyperparathyroidism and malignancy were excluded from the study. Detailed obstetric and medical history was taken from both the cases and controls. Pregnant women in the case group (25(OH)D530 ng/ml) were treated with available 60 000 IU vitamin D (Calcirol – Cadilla 1 g sachet containing 60 000 IU cholecalciferol/vitamin D3) every two weeks in the form of one sachet in one glass of milk, for eight doses or till delivery, whichever was earlier. Iron and calcium supplementation was continued undisturbed [2,3]. In both the cases and controls, cord blood was collected at the time of delivery and tested for 25(OH)D levels. Weight and length measurements were done at birth using digital weighing scale (with accuracy of ±1 g) and infantometer. Head circumference was measured after 36–48 h of birth. The 25(OH)D levels were done using Enzyme Linked Immunofluorescence Assay IFA, with Biomerieux mini VIDAS using appropriate recommendations. Perinatal outcome was noted in both the groups. The classification of vitamin D levels given by Endocrine Society was taken as reference (Table 1) [3]. Statistical analysis was performed by the SPSS program for Windows, version 10.1 (SPSS, Chicago, IL). Continuous variables were presented as mean ± SD, and categorical variables presented as absolute numbers and percentage. Data were checked for normality before statistical analysis. Normally distributed continuous variables were compared using the unpaired t test, whereas the Mann–Whitney U test was used for those variables that were not normally distributed. For more than two groups, ANOVA or the Kruskal–Wallis test was used as appropriate. Categorical variables were analyzed using either the chisquare test or Fisher’s exact test. For all statistical tests, a p value less than 0.05 was taken to indicate a significant difference.
Results Out of 64 booked pregnant women who were screened for vitamin D levels for inclusion in the study (pregnant women with vitamin D levels 530 ng/ml were to be included), 60 were found to have vitamin D levels 530 ng/ml, which were then included as cases in the study for supplementation with vitamin D. All patients were able to complete eight weeks dose no dropout. Hence, the prevalence of vitamin D
Vitamin D (ng/ml) 512 12–20 21–30 Total Median (IQR) (ng/ml)
Frequency
%
30 18 12 60 11.99 (8.0–17.0)
50.0 30.0 20.0 100.0
deficiency was 93.75%. Among the cases 50% of the pregnant women had vitamin D level 512 ng/ml, 30% pregnant women had vitamin D levels in the range of 12–20 ng/ml and 20% in the range of 21–30 ng/ml. Median vitamin D level of the case group was 11.99 ng/ml (Table 2). The majority of pregnant women in the case group (43.3%) were in the age group of 31–35 years. In the control group also, majority (41.7%) were in the same age group of 31–35 years. The mean age in the case group was 30.83 ± 4.0 years and in the control group was 30.65 ± 4.78 years. There was no significant difference in the age profile of the two groups (p ¼ 0.821). The mean period of gestation (POG) in the control group was 37.78 ± 2.12 weeks, while in the case group mean POG was 37.94 ± 0.96 weeks. The mean POG among the two groups was comparable (p ¼ 0.608). Around 56.7% of pregnant women in the case group delivered by LSCS, 33.3% pregnant women had a normal vaginal delivery and 10% had instrumental delivery. In the control group, 58.3% women had LSCS, 36.7% had normal vaginal delivery and 5% had instrumental delivery. There was no significant difference in mode of delivery in the case and control groups (p ¼ 0.286). In the case group 45% women delivered babies with birth weight in the range 3.1–3.5 kg, 35% delivered babies in weight range 2.5–3 kg, 13.3% delivered babies weighing more than 3.5 kg and 6.7% delivered babies with birth weight less than 2.5 kg. In the control group of pregnant women, 26.7% delivered babies weighing in the range 2.5–3 kg and 3.1–3.5 kg, while 31.7% had babies weighing less than 2.5 kg. Around 15% women delivered babies who weighed more than 3.5 kg. The mean birth weight in the cases group was 3.1 ± 0.485 kg and in the control group was 2.8 ± 0.705 kg. There was a significant difference in the birth weight in the case and control groups (p ¼ 0.004, p ¼ 0.012, respectively) (Table 3) (Figure 1). The mean crown heel length of neonates in the case group was 49.35 ± 1.36 cm and in the control group 48.67 ± 2.12 cm. There was a significant difference in the crown heel length of neonates in the case and control groups (p ¼ 0.039). The mean head circumference of neonates in the case group was 34.18 ± 1.31 cm and in the control group 33.88 ± 1.55 cm. There was no significant difference in the head circumference of neonates in the case and control groups (p ¼ 0.255). Around 3.3% neonates in the case groups were born with transient tachypnea and 1.7% had distress. In the control group, 5% neonates had fetal distress and 1.7% had hypocalcemic seizures and respiratory distress syndrome
Vitamin D supplemented and unsupplemented pregnant women
DOI: 10.3109/14767058.2015.1064106
Table 3. Birth weights in the vitamin D supplemented women (cases) and vitamin D unsupplemented (controls). Controls (n ¼ 60) Birth weight 52.5 kg 2.5–3 kg 3.1–3.5 kg 43.5 kg Total Mean ± SD
Frequency
%
19 31.7 16 26.7 16 26.7 9 15.0 60 100.0 2.82658 ± 0.705
Table 4. Cord blood vitamin D levels in newborns of vitamin D supplemented (cases) and unsupplemented pregnant women (controls).
Cases (n ¼ 60) Frequency
%
4 6.7 21 35.0 27 45.0 8 13.3 60 100.0 3.10915 ± 0.485
Controls p value 0.004
0.012
3
Cord blood level of Vitamin D (ng/ml) 512 12–20 20–30 430 Total Median (IQR) (ng/ml)
Frequency
Cases %
31 51.7 18 30.0 9 15.0 2 3.3 60 100.0 11.35 (8.35–17.07)
Frequency
%
p value
0 0.0 50.001 2 3.3 18 30.0 40 66.7 60 100.0 36.5 (29.0–75.0) 50.001
30
J Matern Fetal Neonatal Med Downloaded from informahealthcare.com by RMIT University on 08/20/15 For personal use only.
25 20
vitamin D unsupplemented
15
vitamin D supplemented
10
Column1
5 0 3.5 kg
Figure 1. Bar diagram showing a comparison of birth weight in vitamin D supplemented women (cases) and vitamin D unsupplemented women (controls).
each. There was no significant difference in neonatal outcomes in cases and controls (p ¼ 0.244, 1.000, 1.000, 0.495). Maximum (66.7%) pregnant women in cases had cord blood vitamin D level 430 ng/ml, while 3.3% pregnant women in controls had cord blood vitamin D level 430 ng/ml. Among cases 3.3% pregnant women had cord blood vitamin D level in the range 12–20 ng/ml, 30% had cord blood vitamin D level in the range 20–30 ng/ml and none had cord blood vitamin D level less than 512 ng/ml. In controls maximum (51.7%) pregnant women had cord blood vitamin D levels 512 ng/ml, followed by 30% who had cord blood vitamin D levels in the range 12–20 ng/ml, 15% had cord blood vitamin D levels in the range 20–30 ng/ml and only 3.3% had cord blood vitamin D levels more than 30 ng/ml. The median cord blood vitamin D level was 36.5 ng/ml in cases and 11.35 ng/ml in controls. Around 96.7% cord blood levels were deficient in vitamin D in the control group and 33.3% were deficient in the case group. There was a highly significant difference between cord blood vitamin D levels in cases and controls (p50.001) (Table 4). A significant positive correlation was found between vitamin D levels and cord blood vitamin D levels of cases (r ¼ 0.529, p50.001) (Figure 2).
Discussion 25(OH)D, the storage form of vitamin D, crosses the hemochorial human placenta readily, such that cord blood
25(OH)D concentrations are equal to or up to 20% lower than maternal concentrations [4,5]. Due to its half-life of 2–3 weeks, 25(OH)D is the metabolite that is the most reliable clinical indicator of vitamin D status [6]. Maternal 25(OH)D levels are the most significant regulator of neonatal circulating 25(OH)D concentrations. Vitamin D is required for fetal and neonatal bone development. Maternal vitamin D status affects the neonatal calcium homeostasis during the first 6–8 week of postnatal life. Breast milk is deficient in vitamin D hence sufficient cord blood levels of 25(OH)D ensure adequate supply in early infancy in the exclusively breast fed babies with limited sun exposure [7]. Gestational vitamin D insufficiency has been linked to altered brain development and adult mental health, in particular schizophrenia [8,9]. Inadequate levels of vitamin D during early life may lead to the development of immunological diseases in the offspring later in life such as Type 1 diabetes, allergic diseases and lower respiratory tract infections, wheezing and asthma [10,11]. Various studies worldwide have shown a high prevalence of vitamin D deficiency during pregnancy and in cord blood of newborns at birth [12–17]. There are a few studies on serum 25(OH)D concentration and the prevalence of vitamin D deficiency among pregnant women and neonates from India, all of which have observed a high prevalence of physiologically significant vitamin D deficiency among pregnant women and their newborns, the magnitude of which warrants public health intervention [18–21]. The present study shows that there is a high prevalence of vitamin D deficiency (93.75%). Vitamin D supplementation during pregnancy (with 60 000 IU every two weeks for eight doses or till delivery) leads to a higher cord blood vitamin D levels as compared to pregnancies which did not receive supplementation. The median cord blood vitamin D levels were 36.5 ng/ml in vitamin D supplemented women and 11.35 ng/ml in the unsupplemented women. Around 81.7% cord blood levels were deficient (520 ng/ml) in the vitamin D unsupplemented women but only 3.3% cord blood levels were deficient (520 ng/ml) in the vitamin D supplemented pregnant women. Supplementation with 60 000 IU resulted in optimal level of vitamin D in the cord blood in maximum cases without any toxic levels (4100 ng/ml). There was a highly significant positive correlation between vitamin D levels of vitamin D supplemented women and cord blood vitamin D levels, i.e. as maternal vitamin D levels rise there is a rise in cord blood levels of vitamin D. Neonatal
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J Matern Fetal Neonatal Med, Early Online: 1–5
J Matern Fetal Neonatal Med Downloaded from informahealthcare.com by RMIT University on 08/20/15 For personal use only.
Figure 2. Scatter diagram showing a significant positive correlation of cord blood vitamin D levels with vitamin D levels of cases (vitamin D supplemented pregnant women) (r ¼ 0.529, p50.001).
outcomes were similar in vitamin D supplemented and unsupplemented pregnancies. However, hypocalcemic seizure on day 5 of life was noted in one neonate in the control group (cord blood 25(OH)D level 58 ng/ml). Birth weight and crown heel lengths were significantly higher in neonates born to women supplemented with vitamin D as compared to unsupplemented women. Also a significantly higher number of low birth weight babies were born to unsupplemented women as compared to vitamin D supplemented pregnant women. In a study in 2011, it was concluded that vitamin D3 4000 IU/day was safe and effective in achieving optimal levels of vitamin D in both women and newborns [22]. Another recent study in Dhaka concluded that a regimen of initial dose of 70 000 IU and 35 000 IU/week of vitamin D3 in third trimester of pregnancy attained sufficient levels of vitamin D in all mothers and newborns [23]. In the present study, the dosage schedule was kept two weekly (instead of weekly or daily) as none of the available vitamin D formulations had less than 60 000 IU of vitamin D. Strengths of this study include 100% compliance in all enrolled women. However, due to financial constraints, the reevaluation of the maternal vitamin D levels after complete supplementation/delivery in the case group could not be done and for the same reason controls were not screened for vitamin D levels. Although India is a tropical country with adequate sun exposure, the reason for this high prevalence of vitamin D deficiency during pregnancy may be related to decreased cutaneous synthesis of vitamin D owing to higher skin pigmentation; lower duration as well as surface area exposed to the sun due to greater coverage of body and lesser participation in outdoor activities, primarily vegetarian diet, urban air pollution and no widespread fortification [18].
Indian diet is low in calcium and high in phytates, and contributes to secondary hyperparathyroidism by increased conversion of 25OHD to polar metabolites and inactive 24,25dihydroxyvitamin D3 [24]. At present, vitamin D supplementation is usually not a part of antenatal care programs in India. Although routine iron and calcium supplementation is done in pregnancy and the available calcium supplements contain around 250 IU of vitamin D. Although universal vitamin D screening during pregnancy is debated, most experts agree to screen the high risk women. The high-risk criteria includes south Asian origin, black African, black Caribbean or Middle Eastern origin, women who have limited exposure to sunlight (e.g. those who are predominantly housebound or are generally fully covered when outdoors), women who eat a diet particularly low in vitamin D (e.g. no oily fish, eggs, meat or vitamin D-fortified margarine or breakfast cereal), and women with a body-mass index higher than 30 kg/m2 before pregnancy [3,25,26]. The Indian women definitely belong to the high risk group fulfilling nearly all of the above criteria. Also, there is no consensus on the dose of vitamin D supplementation during pregnancy, which varies from 2000 to 4000 IU daily according to various recommendations [2,3,25–27]. However, these recommendations are formulated by research done in western developed nations where lighter skin pigmentation and more sun exposure (e.g. sunbathing and more outdoor activities) leads to a higher amount of vitamin D being synthesized from sunlight. In these countries the diet is rich in vitamin D containing food and fortification of food products with vitamin D is also prevalent. This is not seen in the Indian scenario, so here the pregnant women might need a higher supplementation dose during pregnancy as compared to their western counterparts.
DOI: 10.3109/14767058.2015.1064106
Vitamin D supplemented and unsupplemented pregnant women
Conclusion From the present study, it can be concluded that supplementation with 60 000 IU of vitamin D3 (every two weeks in for eight doses or till delivery, whichever was earlier) in pregnant women with 25(OH)D levels 530 ng/ml beyond second trimester leads to sufficient levels of 25(OH)D in cord blood at birth in maximum cases as compared to unsupplemented women. Vitamin D supplemented women as compared to unsupplemented women have higher birth weights, increased crown heel length and lesser number of low birth weight babies.
Acknowledgements
12.
13.
14. 15.
16.
17.
J Matern Fetal Neonatal Med Downloaded from informahealthcare.com by RMIT University on 08/20/15 For personal use only.
We thank Dr Navjeet Singh for his kind help and support. 18.
Declaration of interest The authors report no conflicts of interest.
References 1. Ponsonby AL, Lucas RM, Lewis S, Halliday J. Vitamin D status during pregnancy and aspects of offspring health. Nutr J 2010;2: 389–407. 2. Institute of Medicine of the National Academics (US). Dietary reference intakes for calcium and vitamin D. Washington (DC): National Academy Press; 2011. 3. Holick MF, Binkley NC, Bischoff-Ferrari HA, et al. M. Treatment, and prevention of vitamin D deficiency: an endocrine society clinical practice guideline. J Clin Endocrinol Metab 2011;96:1911–30. 4. Fleischman AR, Rosen JF, Cole J, et al. Maternal and fetal serum 1,25-dihydroxyvitamin D levels at term. J Pediatr 1980;97:640–2. 5. Wieland P, Fischer JA, Trechsel U, et al. Perinatal parathyroid hormone, vitamin D metabolites, and calcitonin in man. Am J Physiol 1980;239:385–90. 6. Jefferykc L. Assessing vitamin D status: pitfalls for the unwary. Mol Nutr Food Res 2010;54:1–10. 7. Hyppo¨nen E. Preventing vitamin D deficiency in pregnancy: importance for the mother and child. Ann Nutr Metab 2011;59: 28–31. 8. Liu NQ, Hewison M. Vitamin D, the placenta and pregnancy. Arch Biochem Biophys 2012;523:37–47. 9. Mackay SA, Fe´ron F, Eyles D, et al. Schizophrenia, vitamin D, and brain development. Int Rev Neurobiol 2004;59:351–80. 10. Sørensen IM, Joner G, Jenum PA, et al. Maternal serum levels of 25-hydroxy-vitamin D during pregnancy and risk of type 1 diabetes in the offspring. Diabetes 2012;61:175–8. 11. Morales E, Romieu I, Guerra S, et al., INMA Project. Maternal vitamin D status in pregnancy and risk of lower respiratory tract
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infections, wheezing and asthma in offspring. Epidemiology 2012; 23:64–71. Gale CR, Robinson SM, Harvey NC, et al. Maternal vitamin D status during pregnancy and child outcomes. Eur J Clin Nutr 2008; 62:68–77. Ergu¨r AT, Berberog˘lu M, Atasay B, et al. Vitamin D deficiency in Turkish mothers and their neonates and in women of reproductive age. J Clin Res Pediatr Endocrinol 2009;1:266–9. Haggarty P, Campbell DM, Knox S, et al. Vitamin D in pregnancy at high latitude in Scotland. Br J Nutr 2013;109:898–905. Zhuang XL, Zhu ZW, Zhu DB, et al. Maternal-neonatal vitamin D status and related factors. Zhonghua Er Ke ZaZhi 2012;50: 498–503. Palmer EG, Ramirez-Enriquez E, Frioux SM, Tyree MM. Vitamin D deficiency at birth among military dependants in Hawaii. Hawaii J Med Public Health 2013;72:88–91. Cadario F, Savastio S, Pozzi E, et al. Vitamin D status in cord blood and newborns: ethnic differences. Ital J Pediatr 2013; 39:35. doi: 10.1186/1824-7288-39-35. Jain V, Gupta N, Kalaivani M, et al. Vitamin D deficiency in healthy breastfed term infants at 3 months & their mothers in India: seasonal variation & determinants. Indian J Med Res 2011;133: 267–73. Sachan A, Gupta R, Das V, et al. High prevalence of vitamin D deficiency among pregnant women and their newborns in northern India. Am J Clin Nutr 2005;81:1060–4. Marya RK, Rathore S, Dua V, Sangwan K. Effect of vitamin D supplementation during pregnancy on foetal growth. Ind J Med Res 1988;88:488–92. Marwaha RK, Tandon N, Chopra S, et al. Vitamin D status in pregnant Indian women across trimesters and different seasons and its correlation with neonatal serum 25-hydroxyvitamin D levels. Br J Nutr 2011;106:1383–9. Hollis BW, Johnson D, Hulsey TC, et al. Vitamin D supplementation during pregnancy: double blind, randomized clinical trial of safety and effectiveness. J Bone Miner Res 2011;26: 2341–57. Roth DE, Mahmud AA, Raqib R, et al. Pharmacokinetics of highdose weekly oral vitamin D3 supplementation during the third trimester of pregnancy in Dhaka, Bangladesh. Nutrients 2013;5: 788–810. Harinarayan CV, Ramalakshmi T, Prasad UV, et al. High prevalence of low dietary calcium, high phytate consumption and vitamin D deficiency in healthy south Indians. Am J Clin Nutr 2007;85:1062–7. American College of Obstetricians and Gynecologists. Vitamin D: screening and supplementation during pregnancy. Committee Opinion No. 495. Obstet Gynecol 2011;118:197–8. National Institute for Health and Clinical Excellence. Antenatal care. UK: NICE; 2010. Godel JC. Position statement: vitamin D supplementation: recommendations for Canadian mothers and infants. 2007. Available from: http://www.cps.ca/en/documents/position/vitamin-d [last accessed 2014].
ORIGINAL ARTICLE
Comparison of cord blood vitamin D levels in newborns of vitamin D supplemented and unsupplemented pregnant women: a prospective, comparative study J Matern Fetal Neonatal Med Downloaded from informahealthcare.com by RMIT University on 08/20/15 For personal use only.
Rajesh Nandal1, Rajiv Chhabra1, Deepak Sharma2, Meenakshi Lallar3, Urvashi Rathee4, and Prabhat Maheshwari1 1
Department of Pediatrics, Artemis Health Institute, Gurgaon, Haryana, India, 2Department of Neonatology, Fernandez Hospital, Hyderguda, Hyderabad, Andhra Pradesh, India, 3Department of Obstetrics and Gynecology, SHKM Medical College Mewat, Haryana, India, and 4Department of Obstetrics and Gynecology, Artemis Health Institute, Gurgaon, Haryana, India Abstract
Keywords
Objective: To screen pregnant women for deficiency of 25-hydroxyvitamin D (25(OH)D) and supplement selected vitamin D deficient pregnant women with vitamin D and to compare 25(OH)D levels in cord blood between them. Method: Sixty pregnant women were selected as cases (vitamin D levels 530 ng/ml) and 60 unscreened pregnant women were taken as controls. Cases were supplemented with available 60 000 IU vitamin D every two weeks for eight doses or till delivery, whichever was earlier. In both the cases and controls, cord blood was collected at the time of delivery and tested for 25(OH)D levels using Biomerieux miniVIDAS. Result: Maximum (66.7%) pregnant women who received vitamin D supplementation had cord blood vitamin D level 430 ng/ml, while only 3.3% unsupplemented pregnant women had cord blood vitamin D level 430 ng/ml. The median cord blood vitamin D level was 36.5 ng/ml in vitamin D supplemented and 11.35 ng/ml in unsupplemented women. The mean birth weight and mean crown heel length were 3.1 ± 0.485 kg versus 2.8 ± 0.705 kg and 49.35 ± 1.36 cm versus 48.67 ± 2.12 cm, respectively. Conclusion: Vitamin D supplemented women had sufficient levels of 25(OH)D in cord blood at birth in maximum cases and neonates had higher birth weights and increased crown heel length.
Birth weight, cord blood, crown heel length, 25(OD)D, pregnancy, supplementation, vitamin D
Introduction Vitamin D has a pivotal role in immediate and long-lasting health of the offspring. High prevalence of vitamin D deficiency during pregnancy and resurgence of rickets in infants and toddlers is being increasingly recognized worldwide [1]. The two major forms of vitamin D are vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). Vitamin D2 is obtained from plant sources. Vitamin D3 is mainly obtained in diet from animal sources and it is also synthesized in skin from exposure to UV-B radiation. Less than 10% of vitamin D comes from dietary sources in the absence of food fortification or the use of supplements. Vitamin D deficiency during pregnancy and subsequently in newborns has been observed in studies worldwide. Although vitamin D supplementation during pregnancy is effective in correcting vitamin D deficiency but there is no consensus with regard to dose
Address for correspondence: Dr. Deepak sharma, Department of Neonatology, Fernandez Hospital, Hyderguda, Hyderabad, Andhra Pradesh, India. E-mail: [email protected]
History Received 17 April 2015 Revised 4 June 2015 Accepted 16 June 2015 Published online 18 August 2015
and frequency of vitamin D supplementation during pregnancy. Researchers across the globe have studied vitamin D supplementation during pregnancy in different doses as vitamin D levels and requirements vary with sun exposure, skin color, nutrition, etc., which in turn lead to variable requirements of vitamin D in different populations. Taking into account high prevalence of vitamin D deficiency among pregnant women and their newborns in India and a vital role of vitamin D in neonatal, infant and child health this study was undertaken. The aim of this study was to screen pregnant women for vitamin D deficiency and supplement vitamin D in deficient pregnant women and then compare 25-hydroxyvitamin D (25(OH)D) levels in the cord blood of vitamin D supplemented deficient pregnant women and unsupplemented unscreened pregnant women.
Material and methods The present study was a prospective comparative study conducted during the period November 2013 to May 2014 in a tertiary care hospital in urban Gurgaon. The pregnant women included in the study belonged to upper socioeconomic class. The study was in agreement with the hospital ethics
2
R. Nandal et al.
J Matern Fetal Neonatal Med, Early Online: 1–5
Table 1. The classification of vitamin D levels given by Endocrine Society.
Table 2. Vitamin D levels of pregnant women in the case group. Cases (n ¼ 60)
Level
J Matern Fetal Neonatal Med Downloaded from informahealthcare.com by RMIT University on 08/20/15 For personal use only.
Deficient Insufficient Sufficient Potential toxicity
Range (ng/ml)
Range (nmol/ml)
520 20–29 30–100 4100
550 50–72.5 75–250 4250
committee and human rights committee. Two groups were formed, 60 cases (64 pregnant women were screened by determination of 25(OH)D level at 20 ± 2 weeks of gestation out of which 60 women were found deficient with vitamin D levels 530 ng/ml on screening and were included as cases). Sixty unscreened pregnant women were taken as controls. Pregnant women with multiple pregnancy, chronic renal diseases, atherosclerosis, sarcoidosis, histoplasmosis, hyperparathyroidism and malignancy were excluded from the study. Detailed obstetric and medical history was taken from both the cases and controls. Pregnant women in the case group (25(OH)D530 ng/ml) were treated with available 60 000 IU vitamin D (Calcirol – Cadilla 1 g sachet containing 60 000 IU cholecalciferol/vitamin D3) every two weeks in the form of one sachet in one glass of milk, for eight doses or till delivery, whichever was earlier. Iron and calcium supplementation was continued undisturbed [2,3]. In both the cases and controls, cord blood was collected at the time of delivery and tested for 25(OH)D levels. Weight and length measurements were done at birth using digital weighing scale (with accuracy of ±1 g) and infantometer. Head circumference was measured after 36–48 h of birth. The 25(OH)D levels were done using Enzyme Linked Immunofluorescence Assay IFA, with Biomerieux mini VIDAS using appropriate recommendations. Perinatal outcome was noted in both the groups. The classification of vitamin D levels given by Endocrine Society was taken as reference (Table 1) [3]. Statistical analysis was performed by the SPSS program for Windows, version 10.1 (SPSS, Chicago, IL). Continuous variables were presented as mean ± SD, and categorical variables presented as absolute numbers and percentage. Data were checked for normality before statistical analysis. Normally distributed continuous variables were compared using the unpaired t test, whereas the Mann–Whitney U test was used for those variables that were not normally distributed. For more than two groups, ANOVA or the Kruskal–Wallis test was used as appropriate. Categorical variables were analyzed using either the chisquare test or Fisher’s exact test. For all statistical tests, a p value less than 0.05 was taken to indicate a significant difference.
Results Out of 64 booked pregnant women who were screened for vitamin D levels for inclusion in the study (pregnant women with vitamin D levels 530 ng/ml were to be included), 60 were found to have vitamin D levels 530 ng/ml, which were then included as cases in the study for supplementation with vitamin D. All patients were able to complete eight weeks dose no dropout. Hence, the prevalence of vitamin D
Vitamin D (ng/ml) 512 12–20 21–30 Total Median (IQR) (ng/ml)
Frequency
%
30 18 12 60 11.99 (8.0–17.0)
50.0 30.0 20.0 100.0
deficiency was 93.75%. Among the cases 50% of the pregnant women had vitamin D level 512 ng/ml, 30% pregnant women had vitamin D levels in the range of 12–20 ng/ml and 20% in the range of 21–30 ng/ml. Median vitamin D level of the case group was 11.99 ng/ml (Table 2). The majority of pregnant women in the case group (43.3%) were in the age group of 31–35 years. In the control group also, majority (41.7%) were in the same age group of 31–35 years. The mean age in the case group was 30.83 ± 4.0 years and in the control group was 30.65 ± 4.78 years. There was no significant difference in the age profile of the two groups (p ¼ 0.821). The mean period of gestation (POG) in the control group was 37.78 ± 2.12 weeks, while in the case group mean POG was 37.94 ± 0.96 weeks. The mean POG among the two groups was comparable (p ¼ 0.608). Around 56.7% of pregnant women in the case group delivered by LSCS, 33.3% pregnant women had a normal vaginal delivery and 10% had instrumental delivery. In the control group, 58.3% women had LSCS, 36.7% had normal vaginal delivery and 5% had instrumental delivery. There was no significant difference in mode of delivery in the case and control groups (p ¼ 0.286). In the case group 45% women delivered babies with birth weight in the range 3.1–3.5 kg, 35% delivered babies in weight range 2.5–3 kg, 13.3% delivered babies weighing more than 3.5 kg and 6.7% delivered babies with birth weight less than 2.5 kg. In the control group of pregnant women, 26.7% delivered babies weighing in the range 2.5–3 kg and 3.1–3.5 kg, while 31.7% had babies weighing less than 2.5 kg. Around 15% women delivered babies who weighed more than 3.5 kg. The mean birth weight in the cases group was 3.1 ± 0.485 kg and in the control group was 2.8 ± 0.705 kg. There was a significant difference in the birth weight in the case and control groups (p ¼ 0.004, p ¼ 0.012, respectively) (Table 3) (Figure 1). The mean crown heel length of neonates in the case group was 49.35 ± 1.36 cm and in the control group 48.67 ± 2.12 cm. There was a significant difference in the crown heel length of neonates in the case and control groups (p ¼ 0.039). The mean head circumference of neonates in the case group was 34.18 ± 1.31 cm and in the control group 33.88 ± 1.55 cm. There was no significant difference in the head circumference of neonates in the case and control groups (p ¼ 0.255). Around 3.3% neonates in the case groups were born with transient tachypnea and 1.7% had distress. In the control group, 5% neonates had fetal distress and 1.7% had hypocalcemic seizures and respiratory distress syndrome
Vitamin D supplemented and unsupplemented pregnant women
DOI: 10.3109/14767058.2015.1064106
Table 3. Birth weights in the vitamin D supplemented women (cases) and vitamin D unsupplemented (controls). Controls (n ¼ 60) Birth weight 52.5 kg 2.5–3 kg 3.1–3.5 kg 43.5 kg Total Mean ± SD
Frequency
%
19 31.7 16 26.7 16 26.7 9 15.0 60 100.0 2.82658 ± 0.705
Table 4. Cord blood vitamin D levels in newborns of vitamin D supplemented (cases) and unsupplemented pregnant women (controls).
Cases (n ¼ 60) Frequency
%
4 6.7 21 35.0 27 45.0 8 13.3 60 100.0 3.10915 ± 0.485
Controls p value 0.004
0.012
3
Cord blood level of Vitamin D (ng/ml) 512 12–20 20–30 430 Total Median (IQR) (ng/ml)
Frequency
Cases %
31 51.7 18 30.0 9 15.0 2 3.3 60 100.0 11.35 (8.35–17.07)
Frequency
%
p value
0 0.0 50.001 2 3.3 18 30.0 40 66.7 60 100.0 36.5 (29.0–75.0) 50.001
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25 20
vitamin D unsupplemented
15
vitamin D supplemented
10
Column1
5 0 3.5 kg
Figure 1. Bar diagram showing a comparison of birth weight in vitamin D supplemented women (cases) and vitamin D unsupplemented women (controls).
each. There was no significant difference in neonatal outcomes in cases and controls (p ¼ 0.244, 1.000, 1.000, 0.495). Maximum (66.7%) pregnant women in cases had cord blood vitamin D level 430 ng/ml, while 3.3% pregnant women in controls had cord blood vitamin D level 430 ng/ml. Among cases 3.3% pregnant women had cord blood vitamin D level in the range 12–20 ng/ml, 30% had cord blood vitamin D level in the range 20–30 ng/ml and none had cord blood vitamin D level less than 512 ng/ml. In controls maximum (51.7%) pregnant women had cord blood vitamin D levels 512 ng/ml, followed by 30% who had cord blood vitamin D levels in the range 12–20 ng/ml, 15% had cord blood vitamin D levels in the range 20–30 ng/ml and only 3.3% had cord blood vitamin D levels more than 30 ng/ml. The median cord blood vitamin D level was 36.5 ng/ml in cases and 11.35 ng/ml in controls. Around 96.7% cord blood levels were deficient in vitamin D in the control group and 33.3% were deficient in the case group. There was a highly significant difference between cord blood vitamin D levels in cases and controls (p50.001) (Table 4). A significant positive correlation was found between vitamin D levels and cord blood vitamin D levels of cases (r ¼ 0.529, p50.001) (Figure 2).
Discussion 25(OH)D, the storage form of vitamin D, crosses the hemochorial human placenta readily, such that cord blood
25(OH)D concentrations are equal to or up to 20% lower than maternal concentrations [4,5]. Due to its half-life of 2–3 weeks, 25(OH)D is the metabolite that is the most reliable clinical indicator of vitamin D status [6]. Maternal 25(OH)D levels are the most significant regulator of neonatal circulating 25(OH)D concentrations. Vitamin D is required for fetal and neonatal bone development. Maternal vitamin D status affects the neonatal calcium homeostasis during the first 6–8 week of postnatal life. Breast milk is deficient in vitamin D hence sufficient cord blood levels of 25(OH)D ensure adequate supply in early infancy in the exclusively breast fed babies with limited sun exposure [7]. Gestational vitamin D insufficiency has been linked to altered brain development and adult mental health, in particular schizophrenia [8,9]. Inadequate levels of vitamin D during early life may lead to the development of immunological diseases in the offspring later in life such as Type 1 diabetes, allergic diseases and lower respiratory tract infections, wheezing and asthma [10,11]. Various studies worldwide have shown a high prevalence of vitamin D deficiency during pregnancy and in cord blood of newborns at birth [12–17]. There are a few studies on serum 25(OH)D concentration and the prevalence of vitamin D deficiency among pregnant women and neonates from India, all of which have observed a high prevalence of physiologically significant vitamin D deficiency among pregnant women and their newborns, the magnitude of which warrants public health intervention [18–21]. The present study shows that there is a high prevalence of vitamin D deficiency (93.75%). Vitamin D supplementation during pregnancy (with 60 000 IU every two weeks for eight doses or till delivery) leads to a higher cord blood vitamin D levels as compared to pregnancies which did not receive supplementation. The median cord blood vitamin D levels were 36.5 ng/ml in vitamin D supplemented women and 11.35 ng/ml in the unsupplemented women. Around 81.7% cord blood levels were deficient (520 ng/ml) in the vitamin D unsupplemented women but only 3.3% cord blood levels were deficient (520 ng/ml) in the vitamin D supplemented pregnant women. Supplementation with 60 000 IU resulted in optimal level of vitamin D in the cord blood in maximum cases without any toxic levels (4100 ng/ml). There was a highly significant positive correlation between vitamin D levels of vitamin D supplemented women and cord blood vitamin D levels, i.e. as maternal vitamin D levels rise there is a rise in cord blood levels of vitamin D. Neonatal
4
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Figure 2. Scatter diagram showing a significant positive correlation of cord blood vitamin D levels with vitamin D levels of cases (vitamin D supplemented pregnant women) (r ¼ 0.529, p50.001).
outcomes were similar in vitamin D supplemented and unsupplemented pregnancies. However, hypocalcemic seizure on day 5 of life was noted in one neonate in the control group (cord blood 25(OH)D level 58 ng/ml). Birth weight and crown heel lengths were significantly higher in neonates born to women supplemented with vitamin D as compared to unsupplemented women. Also a significantly higher number of low birth weight babies were born to unsupplemented women as compared to vitamin D supplemented pregnant women. In a study in 2011, it was concluded that vitamin D3 4000 IU/day was safe and effective in achieving optimal levels of vitamin D in both women and newborns [22]. Another recent study in Dhaka concluded that a regimen of initial dose of 70 000 IU and 35 000 IU/week of vitamin D3 in third trimester of pregnancy attained sufficient levels of vitamin D in all mothers and newborns [23]. In the present study, the dosage schedule was kept two weekly (instead of weekly or daily) as none of the available vitamin D formulations had less than 60 000 IU of vitamin D. Strengths of this study include 100% compliance in all enrolled women. However, due to financial constraints, the reevaluation of the maternal vitamin D levels after complete supplementation/delivery in the case group could not be done and for the same reason controls were not screened for vitamin D levels. Although India is a tropical country with adequate sun exposure, the reason for this high prevalence of vitamin D deficiency during pregnancy may be related to decreased cutaneous synthesis of vitamin D owing to higher skin pigmentation; lower duration as well as surface area exposed to the sun due to greater coverage of body and lesser participation in outdoor activities, primarily vegetarian diet, urban air pollution and no widespread fortification [18].
Indian diet is low in calcium and high in phytates, and contributes to secondary hyperparathyroidism by increased conversion of 25OHD to polar metabolites and inactive 24,25dihydroxyvitamin D3 [24]. At present, vitamin D supplementation is usually not a part of antenatal care programs in India. Although routine iron and calcium supplementation is done in pregnancy and the available calcium supplements contain around 250 IU of vitamin D. Although universal vitamin D screening during pregnancy is debated, most experts agree to screen the high risk women. The high-risk criteria includes south Asian origin, black African, black Caribbean or Middle Eastern origin, women who have limited exposure to sunlight (e.g. those who are predominantly housebound or are generally fully covered when outdoors), women who eat a diet particularly low in vitamin D (e.g. no oily fish, eggs, meat or vitamin D-fortified margarine or breakfast cereal), and women with a body-mass index higher than 30 kg/m2 before pregnancy [3,25,26]. The Indian women definitely belong to the high risk group fulfilling nearly all of the above criteria. Also, there is no consensus on the dose of vitamin D supplementation during pregnancy, which varies from 2000 to 4000 IU daily according to various recommendations [2,3,25–27]. However, these recommendations are formulated by research done in western developed nations where lighter skin pigmentation and more sun exposure (e.g. sunbathing and more outdoor activities) leads to a higher amount of vitamin D being synthesized from sunlight. In these countries the diet is rich in vitamin D containing food and fortification of food products with vitamin D is also prevalent. This is not seen in the Indian scenario, so here the pregnant women might need a higher supplementation dose during pregnancy as compared to their western counterparts.
DOI: 10.3109/14767058.2015.1064106
Vitamin D supplemented and unsupplemented pregnant women
Conclusion From the present study, it can be concluded that supplementation with 60 000 IU of vitamin D3 (every two weeks in for eight doses or till delivery, whichever was earlier) in pregnant women with 25(OH)D levels 530 ng/ml beyond second trimester leads to sufficient levels of 25(OH)D in cord blood at birth in maximum cases as compared to unsupplemented women. Vitamin D supplemented women as compared to unsupplemented women have higher birth weights, increased crown heel length and lesser number of low birth weight babies.
Acknowledgements
12.
13.
14. 15.
16.
17.
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We thank Dr Navjeet Singh for his kind help and support. 18.
Declaration of interest The authors report no conflicts of interest.
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