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NUTRITION: Nutrition in Pregnancy


After studying this module you should:

    • Appreciate the marked metabolic changes that occur during pregnancy, postnatally and while breastfeeding.
    • Be able to describe the important micronutrients' that support women’s health.
    • Understand the micronutrients different biological roles for the mother and baby.
    • Appreciate that nutritional needs alter as the woman moves from preconception to pregnancy to breastfeeding.
    • Gain increased confidence when advising and counselling women about micronutrients.


  • Read the clinical review: if you don't have a printed version, click here to download a pdf
  • Complete the online assessment
  • Receive CPD certificate


Reviewed by Nicky Clark RM, RGN, ADM, CERT ED (ADULTS), MA, SFHEA



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    Pre-learning reflection

    Please take a moment to answer these pre-learning questions.  Once completed, click 'next step' below to start this module.  These answers will be logged on your CPD certificate which will be emailed to you on completion as evidence of your learning.

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    Pregnancy and lactation impose heavy nutritional and metabolic demands on mothers: producing a litre of milk takes about 700kcal.1

    Basal metabolic rate rises by about a third from before pregnancy to the 35th week of gestation.2

    Pregnancy is associated with weight gain (by 22% in one study) and increased fat mass (43% increase), especially during the second and third trimesters.3

    The marked metabolic changes that occur during pregnancy and lactation mean that women require a range of micronutrients to support their health before conception, during pregnancy and while breastfeeding. Adequate levels of these micronutrients reduce the risk of certain birth defects and allow women to cope with the considerable metabolic and nutritional demands placed on the mother during pregnancy and lactation.






    Already studied the clinical review? Go straight to the test here
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    Folic Acid


    The UK has the highest rate of neural tube defects in Europe – 0.8 to 1.5 per 1000 births.4

    Normally, the neural tube folds and closes between the 3rd and 4th weeks of pregnancy, forming the brain and spinal cord.
    NTDs arise from incomplete closure of the neural tube, which causes abnormal development of the brain and spinal cord.

    Women of childbearing age should take a supplement containing 400μg folic acid daily before conception and for the first 12 weeks of pregnancy, in addition to consuming folate from a varied diet.

    A mother’s folate requirements continue to increase during pregnancy. Poor folate supply leads to higher plasma homocysteine concentrations, which seems to be associated with an increased risk of placental abruption, stillbirths, very low birth weight, preterm deliveries, pre-eclampsia and clubfoot.5,6






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    Iodine is essential for the synthesis of the thyroid hormones thyroxine and triiodothyronine, which regulate numerous essential enzymatic and metabolic processes.

    The Department of Health recommends adults should receive 140μg of iodine a day.7

    According to National Diet and Nutrition Survey (NDNS) data for 2014/2015 to 2015/2016, 46% of women in the UK aged 19-64 years (childbearing age) have iodine urinary concentration below 100mcg/L.8

    Even mild iodine deficiency during pregnancy can reduce her child’s IQ and undermine school performance. Hypothyroidism seems to increase the risk of complications before, during and after birth. For example, subclinical hypothyroidism in early pregnancy increases the risk of pre-eclampsia by 70%.9





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    Vitamin D


    Calcitriol is the main circulating form of vitamin D, which has a well-established role in calcium and phosphorous homeostasis, promotes bone mineralisation and enhances intestinal absorption of calcium, iron, magnesium, phosphate and zinc. Vitamin D also seems to contribute to the regulation of reproduction.10,11

    The Chief Medical Officers of the UK recommend that pregnant and breastfeeding women take a supplement containing 10μg of  vitamin D to ensure the mother’s requirements for vitamin D are met and to build adequate fetal stores for early infancy.

    In the UK, sunlight from mid-October to the beginning of April does not include the wavelength needed for vitamin D synthesis. So, we rely on vitamin D stored during the summer and food sources. Oily fish is the only significant source of vitamin D in the typical UK diet.12






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    Iron is integral to many proteins in the body, including haemoglobin, lactoferrin and ribonucleotide reductase.5

    Insufficient dietary iron during pregnancy can result in irondeficiency anaemia, which is associated with poor intrauterine growth, higher mortality, premature delivery, low birth weight, and increased perinatal infant mortality.5

    Maintaining adequate iron stores during pregnancy may reduce the risk of postpartum anaemia.5

    Normally, humans absorb about 10% of the iron in the diet. Iron absorption increases during pregnancy. However, demand for  absorbed iron increases about 10-fold in late pregnancy.13 As a result, the mother’s and baby’s iron requirements remain higher than the amount of iron absorbed by most pregnant women.



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    Bones and teeth contain most of the calcium in the human body. But calcium has several other critical roles, such as ensuring  efficient transmission of nerve signals, controlling hormone secretion and allowing muscle contraction.

    During pregnancy, the fetus accumulates about 30g of calcium from the mother. Maternal calcium absorption approximately doubles to compensate for this calcium loss. Healthcare professionals can continue to recommend that adults consume 700mg of calcium a day.

    Breastfeeding mothers need 1250mg of calcium a day. By way of comparison, infants less than 1 year of age needed 525mg of  calcium a day (approximately 450ml of cow’s milk).14



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    Other micronutrients


    Chromium potentiates insulin’s action and is necessary for normal carbohydrate, protein, and fat metabolism.

    Copper is an essential cofactor in several critical enzymes involved in amino acid metabolism and energy production. Copper is critical in the activated form of the enzyme oxygen superoxide, an important free radical scavenger (a compound that deactivates atoms with an unpaired electron that may otherwise damage other molecules).

    Magnesium maintains adequate calcium and potassium levels; helps bones absorb phosphorus as well as regulating heartbeat, muscle contractions, and nerve transmissions.

    Manganese is involved in bone formation and the metabolism of amino acids, cholesterol and carbohydrate.

    Molybdenum is important for normal cell function and maintaining growth.


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    Other micronutrients


    Selenium is a component of several enzymes and is important for male fertility. Selenium deficiencies may increase the risk of gestational complications, miscarriages and the abnormal development of the nervous and immune systems. Low blood concentration of selenium in early pregnancy increases the risk of low birth weight.5

    Vitamin C: Inadequate vitamin C levels during pregnancy are associated with increased risk of infections, premature rupture of membranes, premature birth, and eclampsia.

    Vitamin E is a free radical scavenger and antioxidant, and is essential for the structure and function of the nervous system, retina, and skeletal muscle.

    Zinc ensures the normal function of several enzymes involved in important metabolic pathways, such as nucleic acid and protein metabolism. Zinc is also involved in taste, immune function and normal reproduction and fertility in women through ovulation and the menstrual cycle.16

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    Now that you have reviewed the learning, please complete the following multiple choice questions to test what you've learnt and receive your CPD certificate. 
    When does the neural tube normally fold and close?
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    According to National Diet and Nutrition Survey what percentage of women of childbearing age have iodine urinary concentration below 100mcg/L:
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    Which of the following is iron-deficiency anaemia associated with?
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    Women who are (or may become) pregnant are advised to avoid supplements containing vitamin A and the following sources: (please check all that apply)
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    Vitamin B12 is required for: (please check all that apply)
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    Post-learning reflection

    Please take a moment to answer these post-learning questions.  These answers will be logged alongside your pre-learning responses on your CPD certificate which will be emailed to you on completion as evidence of your learning.

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    References and further reading

    1. Hall Moran V, Lowe N, Crossland N, et al. Nutritional requirements during lactation. Towards European alignment of reference values: the EURRECA network. Maternal & Child Nutrition 2010;6(Suppl2):39-54.
    2. Lof M, Olausson H, Bostrom K, et al. Changes in basal metabolic rate during pregnancy in relation to changes in body weight and composition, cardiac output, insulin-like growth factor I, and thyroid hormones and in relation to fetal growth. The American Journal of Clinical Nutrition 2005;81:678-85.
    3. Bhardwaj S, Verma D, Kapoor S. Body composition and basal metabolic rate in pregnant women. Anthropological Review 2013;76:163.
    4. BMA. Mandatory fortification of flour with folic acid to prevent spina bifida and anencephaly. Parliamentary Brief May 2018.
    5. Allen LH. Multiple micronutrients in pregnancy and lactation: an overview. The American Journal of Clinical Nutrition 2005;81:1206S-12S.
    6. Krauss-Etschmann S, Shadid R, Campoy C, et al. Effects of fish-oil and folate supplementation of pregnant women on maternal and fetal plasma concentrations of docosahexaenoic acid and eicosapentaenoic acid: a European randomized multicenter trial. The American Journal of Clinical Nutrition 2007;85:1392-400.
    7. Hynes KL, Otahal P, Hay I, Burgess JR. Mild iodine deficiency during pregnancy is associated with reduced educational outcomes in the offspring: 9-Year follow-up of the gestational iodine cohort. The Journal of Clinical Endocrinology & Metabolism 2013;98:1954-62.
    8. Bath SC, Steer CD, Golding J, Emmett P, Rayman MP. Effect of inadequate iodine status in UK pregnant women on cognitive outcomes in their children: results from the Avon Longitudinal Study of Parents and Children (ALSPAC). The Lancet 2013;382:331-7.
    9. van den Boogaard E, Vissenberg R, Land J, et al. Significance of (sub)clinical thyroid dysfunction and thyroid autoimmunity before conception and in early pregnancy: a systematic review. Human Reproduction Update 2011;17:605-19.
    10. Lerchbaum E, Obermayer-Pietsch B. Mechanisms in endocrinology: Vitamin D and fertility: a systematic review. European Journal of Endocrinology 2012;166:765-78.
    11. Anagnostis P, Karras S, Goulis DG. Vitamin D in human reproduction: A narrative review. International Journal of Clinical Practice 2013;67:225-35.
    12. NICE. Vitamin D: supplement use in specific population groups. November 2014 (updated August 2017).
    13. Milman N, Bergholt T, Byg K-E, Eriksen L, Graudal N. Iron status and iron balance during pregnancy. A critical reappraisal of iron supplementation. Acta Obstetricia et Gynecologica Scandinavica 1999;78:749-57.
    14. British Dietetic Association. Food Fact Sheet: Calcium Accessed June 2018.
    15. Pieczyŕska J, Grajeta H. The role of selenium in human conception and pregnancy. Journal of Trace Elements in Medicine and Biology 2015;29:31-8.
    16. Cetin I, Berti C, Calabrese S. Role of micronutrients in the periconceptional period. Human Reproduction Update 2010;16:80-95.

    Further Reading
    Duckworth S, Mistry H, Chappell L. Vitamin supplementation in pregnancy. The Obstetrician & Gynaecologist 2012:14(3):175–8.
    Harvey NC, Holroyd C, Ntani G, et al. Vitamin D supplementation in pregnancy: A systematic review. Health Technology Assessment 2014:18:1-190

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