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Iran J Ped Original Article Mar 2008; Vol 18 ( No 1), Pp:25-30

Effect of ­only Contraception on D in

Shahnaz Khaghani*1, PhD of Biochemistry; Narjes Ardestani2, MSc of midwifery; Parvin Pasalar 1, PhD of Biochemistry; Sedigeh Shams1, PhD of Biochemistry; Azin Nowrouzi 1, PhD of Biochemistry; Samira Heidary1, Medical Student

1. Department of Biochemistry, Tehran University of Medical Sciences, Tehran, IR Iran 2. Department of midwifery, Islamic Azad University, Varamin, IR Iran

Received: 18/10/06; Revised: 11/07/07; Accepted: 06/10/07

Abstract Objective: Nowadays progesterone contraceptives are being used by lactating women. In the last century elements effective in growth in infants, such as , phosphorus and have been evaluated. Vitamin D has been mentioned mainly in relation to prevention in infants. This study was initiated in order to investigate the effect of Progestin‐ only contraceptives on milk vitamin D. Material & Methods: In this cohort study 138 lactating women were assigned to either the hormonal (52 participants) or non‐hormonal (86 participants) groups according to their chosen method of contraception. The characteristics and goals of the study were explained in detail and informed consent was obtained from all subjects before inclusion in the study. Research units started their method of contraception 45 (7) days postpartum and continued at least for 6 months afterward. 10 ml milk samples were obtained before the baby nursed at 6 mos postpartum, and kept at ‐20 °C until analysis. Vitamin D levels were measured with RIA method. Findings: Vitamin D levels were found to be 11.2 (7.2) nmol/L in the hormonal and 10.67±6.6 nmol/L in the non‐hormonal groups, which was lower than other cultures. There was not a significant difference between the vitamin D levels of the two groups statistically (P>0.05). Conclusion: According the results, the consumption of progesterone‐only contraceptives had no effect on the vitamin D levels of mothers' milk, although with regard to low levels of vitamin D in the milk of lactating mothers, it is necessary to enrich with vitamin D and for mothers to use vitamin D supplements.

Key Words: Vitamin D; Human milk; Contraceptive; Progesterone‐only contraception

Introduction importance of vitamin D in infancy has been focused on protection from rickets, emerging is re‐emerging as a research suggests that optimal vitamin D significant health problem[1]. While the status may play a role in the protection against

* Correspondence author; Address: Department of clinical biochemistry, Faculty of Medicine, Poursina St, P.O. Box 14155-6447, Tehran, IR Iran E-mail: [email protected] 26 Effect of Progesterone Contraception on Milk VitaminD; Sh Khaghani, et al

the development of other diseases.[2] Scientific minimize exposure should be evidences are linking low circulating 25‐ selected, and protective clothing as well as hydroxyvitamin D to increased risk of sunscreens should be used[10]. But, the use of , , , disease, sunscreen with a protection factor (SPF) , , periodontal disease, of eight reduces the cutaneous production of schizophrenia, tooth loss and autoimmune vitamin D by 97.5% in adults[11]. disorders like multiple sclerosis and Exclusive breast‐feeding is now recom‐ rheumatoid arthritis[3,4]. mended by all international agencies for the During the last decade a greater first 6 mos of life. In spite of its benefits for appreciation has developed for determining infant health and survival[6], is a what factors influence bone accretion poor source of 25‐(OH) D and breastfed in healthy children. Part of this interest can be infants are at higher risk of vitamin D attributed to the suggestion that osteoporosis deficiency than others[5]. Hypovitaminosis D has its origins in childhood. Zamora and co‐ occurs because sun exposure is extremely workers in a retrospective study of limited for both mothers and infants and prepubertal girls found that those who dietary supplementation at the current daily received vitamin D supplements during the 1st recommended intake (DRI) of 400 IU/d is y of life had greater BMD (Bone Mineral inconsequential[12]. Hypovitaminosis D among Density) at the radius, femoral neck, and breast‐fed infants is a severe problem even in greater trochanter[5]. Poor infant skeletal sunlight‐rich environments such as Middle growth and mineralization, and poor infant East[13], being considered in the study of tooth mineralization could be related to Hashemipour S, et al, in Iran, 80% of subjects moderately low plasma 25‐hydroxyvitamin D had mild, moderate or severe hypovitaminosis concentrations[6]. D[14]. Direct exposure to radiation and Lactation is a complex physiological process dietary intake are the two main sources of that is influenced by numerous endogenous vitamin D[3]. Latitude, time of day, season of and exogenous factors. Progestin‐ the year, increased use of sunscreen, amount only oral contraceptive studies have shown a of exposed, pigmentation of the skin and mixture of effects on milk supply, and certain air pollution have a dramatic effect on the forms of progesterone exhibit a dose‐ quantity of vitamin D produced in the skin[7]. dependent suppression of lactation secondary Several studies found relation between breast to peripheral conversion to [15,16,17] milk vitamin D with education, and which is also responsible for a change in milk parity[8]. contents[16]. This study was initiated in order The skin has a high capacity to synthesize to investigate the effect of Progestin‐only vitamin D, but if sun exposure is low vitamin D contraceptives on breast milk vitamin D, and production is insufficient, especially in dark‐ relations between breast milk vitamin D with skinned infants[9]. Many dermatologists who BMI, age and number of parity. are concerned about the anticipated 55000 annual cases of , the most deadly form of , have dismissed the importance of exposure to sunlight. Despite the high prevalence of vitamin D insufficiency, Material & Methods these experts consider the health risks to be small compared with the danger of The study was carried on lactating mothers, melanoma.[4] Furthermore, the centers for attending Tehran health‐care centers (2006). Disease Control and Prevention, AAP They started their method of contraception (American Academy of Pediatrics) and the 45(±7) days postpartum and continued at American Cancer Society warned people to least for 6 months afterward. The limit exposure to ultraviolet light to decrease characteristics and goals of the study were the incidence of skin cancer. Even infants explained in detail and informed consent was younger than 6 months should be kept out of obtained from all subjects before inclusion in direct sunlight, children’s activities that the study. Iran J Pediatr. Vol 18 (No 1); Mar 2008 27

In this cohort study 138 lactating women Mean (and standard deviation) of breast were assigned to either the hormonal (52 milk vitamin D in hormonal group was 11.2 participants) or non‐hormonal (86 (7.2) and in non‐hormonal group was 10.7 participants) groups according to their chosen (6.6). The difference was not statistically method of contraception. The subjects, based significant (P>0.05). on their contraceptive method were divided Breast milk vitamin D didn’t relate with into two groups, 52 women received maternal BMI and education (P>0.05), progesterone‐only methods [Progesterone however Vitamin D in breast milk increased Only Pill (POP) or Depoedroxy Progesterone until third parity (P<0.05). Acetate (DMPA)] and 86 of them received non‐ hormonal contraception [Intra Uterine Device (IUD), Condom or sterilization]. All the mothers were apparently healthy. The characteristics of two groups were similar at Discussion the time of admission; none of them received Global high prevalence of vitamin D vitamin D supplement. insufficiency specially in Iran and re‐ At 6 month postpartum, before nursing the emergence of rickets, even in industrialized baby, 10 ml of each mother’s milk were countries despite fortifying some foods, and expressed. Samples were frozen immediately the growing scientific evidence are linking low after collection and stored at ‐20˚C until circulating 25‐hydroxyvitamin D to increased analysis was carried out. Vitamin D content of risk of osteoporosis, diabetes, cancer, each sample was measured by the RIA autoimmune disorders and some other method. diseases, motivated us to do this investigation. Two groups were compared at entrance Adequate concentration of circulating 25‐ into the study, for determination of potential hydroxyvitamin D [25 (OH) D] is critical to differences with respect to sociodemographic maintaining the health and function of the and baseline clinical characteristics. Statistical immune, reproductive, musculoskeletal and analysis was performed using SPSS version 12. of men and women of Student’s t‐test and X2 were used for all ages and races[4]. evaluation. Human milk typically contains a vitamin D concentration of 25 IU/L or less. Breastfed infants are at increased risk of developing vitamin D deficiency or rickets[10]. Vitamin D Findings deficiency prevalence is much higher in Asian countries; the studies carried out in the The groups did not differ according to age, preceding two decades have shown a high weight, height, BMI, education, occupation, prevalence of vitamin D deficiency in tropical number of , infant sex and birth countries such as China, Turkey, India, Iran weight. The baseline characteristics of the and Saudi Arabia and some other Asian subjects in two groups are shown in table 1. countries[17‐25].

Table 1‐ The characteristics of two groups at the time of admission Mothers Hormonal Non­hormonal N=138 N=52 N=86 Age 25.11 44224.77 BMI (Kg/m2) 24.26 25.84 Parity 11.79 1.1.81 Human milk vitamin D* 11.19 10.67 *The difference between mean of breast milk vitamin D in hormonal group and in non‐hormonal group was not statistically significant (P>0.05). 28 Effect of Progesterone Contraception on Milk VitaminD; Sh Khaghani, et al

Vitamin D deficiency can result in rickets, a little time spent outside home, air pollution, painful disease characterized by softening of sunscreen use contribute to vitamin D and growth plates. In Canada, it was deficiency. reported that 85% of all patients suffering There are other hypotheses to explain rickets had been breastfed[26]. Also, In Iran, vitamin D deficiency among Asians. Awumey Rafii reported 29% of 140 cases of rickets in et al showed higher activity level of 24‐ Bahrami Children’s Hospital were less than six hydroxylase in fibroblasts of Asian Indians in months of age[25]. Even moderately low plasma America compared with controls. Therefore, 25‐hydroxyvitamin D concentrations observed increased vitamin D catabolism may cause in Parisian women at the end of winter were vitamin D deficiency in Asians[31]. associated with poor fetal and infant skeletal Obese individuals, as a group, have low growth and mineralization, and poor infant plasma concentrations of 25(OH) D, obesity tooth mineralization[28]. impairs vitamin D utilization in the body, In the present study breast milk vitamin D meaning obese people need twice as much in both groups was low, and no statistically vitamin. Wortsman et al found BMI was significant difference was observed between inversely correlated with serum vitamin D3 the two groups. concentrations after irradiation and with peak In a study in Tehran that was carried out by serum vitamin D2 concentrations after vitamin [8] Hashemipour et al, 1210 adults ranging D2 intake . However in this study no between 20 and 64 years old were randomly relationship was found between breast milk selected and their serum levels of 25(OH) D vitamin D content and BMI of the mothers. were measured. It showed that, prevalence of Pehlivan et al, in Turkey found no severe, moderate and mild Vitamin D correlation between the parity and vitamin D deficiency were 9.5%, 57.6% and 14.2%, deficiency[3], but in this study we found respectively[14], which was similar to our correlation between the number of results. Also, in a series of 82 wrist X‐rays pregnancies and breast milk vitamin D, that performed for children less than 5 years of age was the vitamin D increase till third parity and admitted to a hospital in Tehran, signs of the decrease afterwards. rickets were reported in 15% of the cases[27]. In the same study from Turkey, Ismail and Direct exposure to ultraviolet radiation and colleagues found positive correlation between dietary intake are the two main sources of serum 25‐OH‐vitD level and educational vitamin D. The skin has a high capacity to status[7]; however, we found no relationship synthesize vitamin D, but if sun exposure is between education and vitamin D in mothers' low vitamin D production is insufficient, milk. especially in dark‐skinned infants[5]. Some Dermatologists and cancer experts advise factors like air pollution, pigmentation of the caution in exposure to the sun, especially in skin, latitude, time of day, season of the year, childhood, and recommend regular use of use of sunscreen, dressing habits have a sunscreens. Sunscreens markedly decrease dramatic effect on the quantity of vitamin D vitamin D production in the skin. Further‐ produced in the skin[3,7,10,29,30]. more, the Centers for Disease Control and In India, in a study enrolling 9‐24 month‐ Prevention, with the support of many old infants with the same socioeconomic organizations including the American conditions and no vitamin D supplementation, Academy of Pediatrics (AAP) and the the group living in the region with intensive American Cancer Society, have recently air pollution had lower serum 25‐ launched a major public health campaign to hydroxyvitamin D levels than those living in decrease the incidence of skin cancer by the country with no air pollution (12.6 nmol/L urging people to limit exposure to ultraviolet versus 28.2 nmol/L)[30]. Tehran, the site of light. Indirect epidemiologic evidence now audit, has intensive air pollution that prevents suggests the age at which direct sunlight optimal exposure to sunlight. In addition, exposure is initiated is even more important mothers' dressing habits, low dietary vitamin than the total sunlight exposure over a lifetime D intake, lack of vitamin supplementation, in determining the risk of skin cancer. Thus, Iran J Pediatr. Vol 18 (No 1); Mar 2008 29

guidelines for decreasing exposure include Conclusion directives from the AAP that infants younger than 6 months should be kept out of direct According to the results, the consumption of sunlight, children’s activities that minimize progesterone‐only contraceptives had no sunlight exposure should be selected, and effect on the vitamin D levels of mothers' milk, protective clothing as well as sunscreens although with regard to low levels of vitamin should be used[10]. D in the milk of lactating mothers, it is We found no previous study about this necessary to enrich foods with vitamin D and subject, but on the basis of this audit no for mothers to use vitamin D supplements. correlation was found between human milk 25(OH) D level in two groups, so it seems POP and DMPA do not have any adverse effects on vitamin D. However, further study is needed to Acknowledgment demonstrate these findings. As seen in our results and that of Hashemipour et al there is The authors wish to thank the support of Vice serious maternal vitamin D deficiency in Chancellor of Tehran University of Medical Tehran. Due to the vitamin D deficiency Sciences. The authors also wish to thank Dr observed in this study and related ones, it is Ebrahim Javadi from biochemistry really emphasized to enrich foods with department of Tehran University of Medical vitamin D, to use vitamin D supplements in Sciences for their help in all stages of this mothers, and to educate them research. how to conquer vitamin D deficiency. Some authors believe a RDA of 400 IU/d (10µg/d) in adults seems woefully inadequate to maintain normal circulating concentrations of vitamin D in adults with minimal solar References exposure that dermatologists recommended. 1. Thomson K, Morley R, Grover SR, et al.

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