Oxford Handbook of Midwifery (31 page)

These 400micrograms supplements are available on prescription, and are easily obtainable from pharmacies and health food shops. For women who have had a previously affected baby, a 5mg supplement is prescribed.

Some countries, for example the USA, have introduced mandatory fortification of flour used in food production with folic acid, in an effort to reduce the risk of NTDs even further. Such a strategy has been widely debated in the UK, but so far has been rejected on the grounds of masking the symptoms of vitamin B
₁₂
deficiency, issues for older people, technical aspects, and consumer choice.

1
Department of Health (1992).
Folic Acid and the Prevention of Neural Tube Defects: Report from an Expert Advisory Group
. London: DH.

CHAPTER 5
Health advice in pregnancy

92‌‌

Iron

Iron (Fe) is an essential mineral that has several important functions in the body. As an important component of the proteins haemoglobin and myoglobin, it carries oxygen to the tissues from the lungs; it is also a nec- essary component of some enzyme reactions. It is stored in the body in the form of the protein ferritin and haemosiderin; the amount of ferritin in serum is a useful indictor of body iron stores. Transferrin is an important protein involved in transporting iron within the body and delivering it to cells.

About 0.5–1mg/day is shed from the body in urine, faeces, sweat, and cells shed from the skin and gastrointestinal tract. High menstrual losses and increased requirements of pregnancy contribute to the higher incidence of iron deficiency in women of reproductive age. The body usually maintains iron balance by controlling the amount of iron absorbed from food.

There are two forms of iron in the diet: haem iron and non-haem iron. Haem iron in meat, fish, and poultry is absorbed very efficiently; this is not influenced by iron status. Non-haem iron, in cereals and pulses, is not as well absorbed as haem iron, but absorption is influenced by iron

status and several other dietary factors. Approximately 10–15% of dietary

iron is absorbed. Iron absorption follows a log linear response, in that when iron stores are high, absorption decreases, protecting against iron overload, and conversely, absorption increases when iron stores are low. Absorption is favoured by factors such as the acidity of the stomach, which maintains iron in a soluble form in the upper gut (in the ferrous form, Fe
²
+
, rather than the ferric form, Fe
³⁺
). Non-haem iron absorption is improved significantly when meat proteins and vitamin C are present in the diet. Factors that can significantly inhibit iron absorption include calcium, phenolic compounds in tea, coffee, cocoa and some herbs, phytates in seeds, nuts, vegetables and fruit, and soya protein.

Demand for iron is increased during pregnancy because of the increased RBC mass and fetal growth. The need for iron is minimal in the first trimester but increases throughout pregnancy, with a substantial increase during the third trimester. The absence of menstruation, body stores, and increased absorption are believed to compensate for the increased demand.
¹
Routine iron supplementation is no longer advocated, but supplementation may be necessary for women with low levels at the beginning of pregnancy.
²

Iron deficiency results in a microcytic anaemia, and maternal anaemia during pregnancy is associated with an increased risk of preterm delivery.
³
The physiological changes in plasma volume and RBC mass make measurements of haemoglobin concentration unreliable in pregnancy; therefore, for the purposes of screening, serum ferritin is the best single indicator of storage iron, provided a cut-off point of 30micrograms/L is used.
⁴

IRON

93

Recommended reading

Evans M (2008). Iron deficiency through the female life cycle—who should care?
MIDIRS Midwifery Digest
18
(37), 404–8.

Webster-Gandy J, Madden A, Holdsworth M (2006).
Oxford Handbook of Nutrition and Dietetics
. Oxford: Oxford University Press.

1. Expert Group on Vitamins and Minerals (2003).
   Risk Assessment Iron
   . Available at: M www.food.
   gov.uk/multimedia/pdfs/evm_iron.pdf (accessed 4 August 2004).
   
2. Department of Health (1991).
   Dietary Reference Values for Food Energy and Nutrients for the United Kingdom
   . Report on health and social subjects 41. London: HMSO.
   
3. Scholl T, Reilly T (2000). Anemia, iron and pregnancy outcome.
   Journal of Nutrition
   130
   , 443S–7S.
   
4. Van den Broek NR, Letsky EA, White, SA Shenkin A (1998). Iron status in pregnant women: which measurements are valid?
   British Journal Haematology
   103
   (3), 817–24.
   

   CHAPTER 5
   Health advice in pregnancy
   

   94‌‌
   

   Peanut allergy
   

   Peanut allergy is a serious adverse reaction to the proteins found in peanuts. The symptoms of peanut allergy vary from a mild, itchy rash or tingling around the mouth, to a severe, life-threatening situation that can include breathing difficulties and collapse. The number of individuals affected with peanut allergy is increasing, and it is suggested that the prevalence is around 1:200. Peanut allergy appears to be a lifelong condi- tion, although the severity and nature of the symptoms may change, and approximately 25% of children with peanut allergy will grow out of it.
   

   Peanuts (also called groundnuts or monkey nuts) are classified as a vegetable as they belong to the legume family (and are thus related to peas, beans, and lentils). They were introduced into the UK around the time of the Second World War and are now used in the manufacture of a wide range of foods. Cooking or roasting peanuts does not alter the allergenicity of these proteins, therefore both fresh and roasted peanuts may evoke a reaction. Many people have multiple allergies, therefore reactions to other legume proteins may occur, although this is less common. However, individuals allergic to peanuts do react more commonly to tree nuts, such as brazil, almond, and hazel.
   

   The development of allergy or allergic disease is hereditary and known
   

   to occur more commonly in people who have other atopic conditions, such as eczema, asthma, or hay fever, or who have at least one close relative with such conditions.
   

   Pregnancy, breastfeeding, and weaning
   

   Although the research is inconclusive, it has been suggested that sensi- tization can occur
   in utero
   or through breastfeeding, as peanut protein has been detected in breast milk. However, the Department of Health’s Committee on Toxicity of Chemicals in Food, Consumer Products and the Environment has recently completed a review and has concluded that there is no evidence that eating or refraining from eating peanuts has any bearing on a child acquiring peanut allergy. Therefore the revised advice is as follows:
   ¹
   

   • Pregnant or breastfeeding women who wish to consume peanuts as part of a healthy diet may do so irrespective of any family history of allergies.
     ¹
     
   • There is no reason for pregnant or nursing mothers who do not fall into this category to avoid eating peanuts, unless they themselves have a peanut allergy.
     
   • The Department of Health recommends that all infants be exclusively breastfed for 6months. If a mother decides to introduce solid food before this time she should avoid peanuts or other allergic-type foods such as nuts, seeds, milk, eggs, wheat, and fish. When introduced, these foods should be given one at a time so that any allergic reaction is more easily identified.
     ²
     

PEANUT ALLERGY

95

is advised that parents consult their GP or health visitor before giving peanuts or peanut-containing foods to their baby for the first time. There is no evidence to suggest that avoiding peanut consumption until 3 years of age will prevent peanut allergy.
^1,2

1. Department of Health (2009).
   Revised Government Advice on Consumption of Peanut During Pregnancy, Breastfeeding and Early Life and Development of Peanut Allergy
   . London: DH.
   
2. Committee on Toxicity (2009).
   Statement on the Review of the 1998 COT Recommendations on Peanut Avoidance.
   London: Food Standards Agency. Available at: M http://cot.food.gov.uk/
   cotstatements/cotstatementsyrs/cotstatements2008/cot200807peanut (accessed 2.3.11).
   

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   Health advice in pregnancy
   

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   Exercise
   

   There are many benefits to be gained from taking exercise such as brisk walking, swimming, and gentle aerobic exercise during pregnancy:
   

   • A more positive, healthy outlook during pregnancy.
     
   • Greater ability to cope with the discomforts of pregnancy and labour.
     
   • Less need for induction of labour, epidural analgesia, and caesarean section.
     
   • The improvement in muscle tone, strength, and endurance resulting from regular exercise can prepare the woman for the physical stresses of labour and caring for the baby afterwards.
     
   • After delivery, regaining the normal pre-pregnancy weight is easier.
     

     Limiting factors
     

     Certain situations that arise in pregnancy may limit the amount of exercise it is safe to take, or may make exercise contraindicated. The woman should seek medical advice prior to exercising if she has any of the following:
     

   • Preterm rupture of the membranes
     
   • Pregnancy-induced hypertension
     
   • Antepartum haemorrhage
     

     •
     History of premature labour or several miscarriages
     

   • Muscle or joint problems
     
   • Multiple pregnancy
     
   • Low back pain
     
   • Medical conditions, such as existing heart disease.
     

     Advice
     

     Provided there are no other problems and the woman is otherwise healthy, the following advice should be given regarding safe exercise during pregnancy.
     

     For women who are used to regular exercise
     

   • Drink water before, during, and after exercise.
     
   • Do not undertake any exercise that results in becoming overheated. The fetus does not cool down as quickly as the mother and its oxygen requirements remain raised for longer.
     
   • Start exercise gradually, as the body rapidly shifts oxygen and energy towards the working muscles. Lower the intensity of aerobic exercise and monitor her heart rate regularly throughout the exercise period.
     
   • Avoid any exercise causing loss of balance and sports with a high risk of falling. Avoid bouncing and jerking movements and deep knee bends that put a strain on the hip and leg joints
     
   • Stop immediately if any exercise causes dizziness, faintness, shortness of breath, nausea, contractions, vaginal bleeding, or fluid leakage.
     

     If the mother is new to regular exercise
     

   • Start very slowly, with a 10–15min period of gentle exercise.
     
   • Gradually increase this to 30min as she becomes more familiar with the routine.
     

Most gyms and fitness clubs have trained attendants who can devise a programme for the pregnant and newly postnatal woman. It is safe to exercise for 30–40min, three times per week.

EMPLOYMENT

97‌‌

Employment

Many women want to continue to work during their pregnancy and there is legal protection for women who wish to do so.

A woman is not legally obliged to inform her employer of her pregnancy until she gives notice of the date she intends to start her maternity leave. That notification must be given by 15 weeks before the expected week of childbirth at the latest, i.e. when the woman is approximately 6 months pregnant.

It is advisable for the woman to inform her employer of her pregnancy, as she is entitled to certain rights: