Chapter 5
83Preconception care
The period before conception is increasingly regarded as important for the health of pregnant women and future generations. Successive reports from the Centre for Maternal and Child enquiries1,2 conclude that lack of pre-conception care is a contributory factor in maternal deaths, whilst evidence from life course epidemiology3,4 and epigenetics5 highlights the importance of the intrauterine environment in determining chronic disease risk in child-hood and adultchild-hood. factors, such as maternal diet and nutritional status, which can be modified before conception, have an important influence on the intrauterine environment and fetal development. Consequently, the preconception period is seen as a critical period where intervention can lead to both short- term benefit, by reducing pregnancy complications and adverse birth outcomes, and long- term health gain, as emphasized in the wHO Global Action Plan for the Prevention and Control of Non- communicable Diseases 2013– 2020.6
Fetal programming
Pregnancy is a critical time for healthy fetal development as the fetus relies heavily on maternal stores and nutrient intake for optimal growth. Nutrition and weight management before and during pregnancy are already known to have a profound effect both on the development of the fetus and health outcomes later in life. However, fetal programming (based on Barker’s hypothesis)7 is an emerging concept discovering links between environ-mental conditions during embryonic and fetal development and the risk of diseases later in life.
The fetal environment is influenced by several factors, including the intake of macro- and micronutrients and toxic compounds by the mother.
The genome as such is not changed in the programmed individual, but the causative factors may affect the expression of genes in a way that has lasting effects on the metabolic functions. The critical issue is that fetal program-ming is even transmitted to the next generations. However, the molecu-lar mechanisms that are involved in this fetal programming are far from understood, and the Centre for fetal Programming8 is aiming to unravel the impact of maternal dietary factors on childhood health.
The concept of fetal programming has gained increased credence sup-ported by strong findings from human epidemiologic studies and animal models.9 Specifically, in utero exposures to altered maternal nutrition (excess and deficient), stress (e.g. glucocorticoids), or environmental toxins, among others, may alter organ structure or function. As approximately 50% of all cell divisions for growth occur from conception to birth, it is not surprising that environmental stresses may impact cell number. Although the genotype of programmed offspring does not change, modified gene expression may be a consequence of exposure- mediated epigenetic changes, thus altering the expression of regulatory peptides and organ function.
The word ‘programming’ illustrates the idea that during critical periods in early fetal development, there are persisting changes in fetal body structure and function that are caused by environmental stimuli.
This theory links to the concept of ‘developmental plasticity’ where our genes are believed to express different ranges of physiological or
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morphological states, in response to the environmental conditions which were encountered during our fetal development.9 for example, if the mother has an inadequate diet whilst pregnant, then this signals that liv-ing conditions in the long term will be impoverished; consequently the fetus adapts by changing its body size and metabolism to prepare for food shortages after birth. Physiological and metabolic processes in the body subsequently undergo long- term changes as a result of this restricted fetal growth.10
epidemiological observations as well as clinical and experimental stud-ies support the concept of fetal programming as the origin of a number of diseases, including obesity, type 2 diabetes, and allergic diseases. It is also believed that maternal conditions, such as cardiovascular disease and hypertension, during pregnancy can have long- term effects upon the adult health of the fetus. Several exposures during pregnancy have already been indicated to have an impact.8
Asthma and allergic disease
• environmental: exposure to polychlorinated biphenyl compounds in pregnancy is associated with an increased risk of asthma in the children at age 20 years.
• Diet: peanut, nut, and fish consumption in pregnancy are found to be associated with a lower risk of child asthma and allergic rhinitis;
conversely, intake of low- fat yoghurt and artificially sweetened beverages were identified as risk factors.
• vitamin D: a high maternal vitamin D concentration might be associated with an increased risk of allergic diseases in offspring.11
Metabolic disease
• Maternal exposure to perfluorinated compounds (environmental pollutants) may be associated with an increased propensity for obesity in young adult women.
• Protein intake: high maternal protein intake in pregnancy may increase the risk of overweight children.
Reproductive outcomes
• Maternal smoking in pregnancy was associated with an earlier age of menarche in their daughters.
• fetal exposure to perfluorinated compounds resulted in altered reproductive function later in life. This was specifically related to poorer semen quality and reproductive hormone profile measures in young men.
Epigenetics
As more is understood about the human genetic make- up, a number of genes (alleles) that determine how individuals respond to various expo-sures have been identified. It is already known that there are differences in the type of gene that individuals have— one person may have type 1 of a particular gene, whilst another person has type 2 or type 3 of that same gene. Scientists have now discovered that these different gene types react in different ways to prenatal exposures and events. for example, it has been
shown that a person with a type 1 gene may deal very well with stress and the child will be of normal birthweight, while the type 2 person will have an excessive amount of cortisol and this infant will be programmed for later anxiety problems.
The fetal environment is influenced by several factors, including the intake of macro- and micronutrients and toxic compounds by the mother.
The genome as such is not changed in the programmed individual, but the causative factors may affect the expression of genes in a way that has last-ing effects on the metabolic functions. The critical issue is that fetal pro-gramming is even transmitted to the next generations. There is thus much current research to explore, examine, and understand the impact of envi-ronmental factors working during the fetal period and how these factors may interact with genetic factors and with environmental factors working prior to or after this period in determining the development, the health, and specific diseases appearing during the life course of the individual.
The genotype of the mother has also been shown to be related to the number of alcohol- related physical features that the baby will show. In par-ticular, if the mother has the ADH2- 2 allele, which leads to a more rapid clearing out of alcohol from her body, then her infant is not likely to have alcohol- related birth defects.
Studies of this kind will help to determine which women are at high risk for having a baby with later problems.
Relevance to midwifery care
Many women are motivated to adopt healthier behaviours in the preconcep-tion period and yet, despite a high level of pregnancy planning, awareness of preconception health among women and health professionals is low, whilst the individual responsibility for providing preconception care is sometimes unclear.12 However, as both epidemiologic and epigenetic research findings suggest that focusing on pre- pregnancy intervention by health professionals would not merely benefit the ‘worried well’ or women with specific medical disorders but could be an effective approach to addressing important health inequalities relating to smoking, alcohol, obesity, and other risky behaviours, it must be a priority in contemporary midwifery care.
References
1 Lewis G (ed.) (2007). The Confidential Enquiry into Maternal and Child Health (CEMACH). Saving Mothers’ Lives: reviewing maternal deaths to make motherhood safer: 2003– 2005. The Seventh Report on Confidential Enquiries into Maternal Deaths in the United Kingdom. London: CeMACH.
2 Centre for Maternal and Child enquiries (CMACe) (2011). Saving Mothers’ Lives. Reviewing mater-nal deaths to make motherhood safer: 2006– 2008. The Eighth Report of the Confidential Enquiries into Maternal Deaths in the United Kingdom. BJOG 118(Suppl 1): 1– 203.
3 Hanson M, fall C, Robinson S, Baird J, BMA Board of Science (2009). Early Life Nutrition and Lifelong Health. London: British Medical Association.
4 Ben- Shlomo Y, Kuh D (2002). A life course approach to chronic disease epidemiology: conceptual models, empirical challenges and interdisciplinary perspectives. Int J Epidemiol 31: 285– 93.
5 Gluckman P, Hanson M, Buklijas T, Low f, Beedle A (2009). epigenetic mechanisms that underpin metabolic and cardiovascular diseases. Nat Rev Endocrinol 5: 401– 8.
6 world Health Organization (2013). Global Action Plan for the Prevention and Control of Non- communicable Diseases 2013– 2020. Geneva: world Health Organization.
7 Barker DJP (2004). The developmental origins of adult disease. J Am Coll Nutr 23: 588S– 95S.
8 Centre for fetal Programming (2014). About fetal programming. Available at: M www.cfp- research.
com/ About%20CfP/ About%20fetal%20programming.aspx.
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9 Bateson P (2001). fetal experience and good adult design. Int J Epidemiol 30: 928– 34.
10 Jørgensen Sw, Brøns C, Bluck L, et al. (2015). Metabolic response to 36 hours of fasting in young men born small vs appropriate for gestational age. Diabetologia 58: 178– 87.
11 Hansen S, Maslova e, Strom M, et al. (2015). The long- term programming effect of maternal 25- hydroxyvitamin D in pregnancy on allergic airway disease and lung function in offspring after 20 to 25 years of follow- up. J Allergy Clin Immunol 136: 169– 76.e2.
12 Royal College of Midwives (2012). Maternal Emotional Wellbeing and Infant Development: A Good Practice Guide for Midwives. London: Royal College of Midwives.