Fetal programming: Difference between revisions

Revision as of 08:02, 24 November 2018

Revision as of 08:07, 24 November 2018

Line 1:

{{copy edit|date=November 2018}}

'''Fetal programming''', also known as '''prenatal programming''', is a theory which suggests that the environment surrounding the [[fetus]] during its developmental phase plays a seminal role in determining its disease risk during the later stages.

Three main forms of programming that occur due to changes in the maternal environment are:

Line 14:

=== Dutch famine 1944-45 ===

In 1944-45, setting up of German blockade led to lack of food supplies in the [[Netherlands]], which later was described as the [[Dutch famine of 1944–45|Dutch famine]]. Occurrence of this famine led to the population - including women in various stages of pregnancy - suffering from severe malnutrition. The Dutch Famine Birth Cohort Study examined the impact of lack of nutrition on children born during or after this famine. It showed that over the course of their lifetime, These children were at greater risk of suffering from [[Diabetes mellitus|diabetes]], [[cardiovascular disease]], [[obesity]], and other [[Non-communicable disease|non-communicable diseases]].

=== Barker Hypothesis ===

In the 1980’s [[David Barker (epidemiologist)|David Barker]] began a research study on this topic. The Barker Hypothesis, or [[Thrifty phenotype]], forms the basis for much of the research conducted on fetal programming. This hypothesis states that if the fetus is exposed to low nutrition, it will adapt to that particular environment. Nutrients are diverted towards the development of heart, brain, and other essential organs of the fetus. The body also undergoes metabolic alterations that ensure survival in spite of low nutrition but may cause problems in situations with normal or high nutrition.<ref>{{cite journal | vauthors = Remacle C, Bieswal F, Reusens B | title = Programming of obesity and cardiovascular disease | journal = International Journal of Obesity and Related Metabolic Disorders | volume = 28 Suppl 3 | issue = S3 | pages = S46–53 | date = November 2004 | pmid = 15543219 | doi = 10.1038/sj.ijo.0802800 }}</ref> This leads to increased risk of developing [[metabolic syndrome]].

== Nutritional Statusstatus ==

The developing fetus forms an impression of the world into which it will be born via its mother’s nutritional status. Its development is thus modulated to create the best chance of survival. However, excessive or insufficient nutrition in the mother can provoke maladaptive developmental responses in the fetus, which in turn manifest in form of post-natal diseases. It is possible that this has such a profound effect on the fetus’ adult life that it can even outweigh lifestyle factors.<ref name = "Fleming_2012" />

=== Excessive nutrition ===

BMI[[Body mass index]] prior to pregnancy and weight gain during pregnancy are both linked to high blood pressure in the offspring during adulthood. Mouse models suggest that this is due to high levels of fetal hormone [[leptin]], which is present in the blood of individuals that are overweight or obese. There is a theory that this hormone has a negative impact on regulatory systems of the fetus, and renders it impossible to maintain normal blood pressure levels. <ref>{{cite journal | vauthors = Taylor PD, Samuelsson AM, Poston L | title = Maternal obesity and the developmental programming of hypertension: a role for leptin | journal = Acta Physiologica | volume = 210 | issue = 3 | pages = 508–23 | date = March 2014 | pmid = 24433239 | doi = 10.1111/apha.12223 }}</ref>

=== Insufficient nutrition ===

Line 29:

== Hormonal influence ==

A delicate balance of hormones during pregnancy is regarded as being highly relevant to fetal programming and may significantly influence offspring outcomes.<ref name="Hoffman_2016">{{cite journal | vauthors = Hoffman MC | title = Stress, the Placenta, and Fetal Programming of Behavior: Genes' First Encounter With the Environment | journal = The American Journal of Psychiatry | volume = 173 | issue = 7 | pages = 655–7 | date = July 2016 | pmid = 27363547 | doi = 10.1176/appi.ajp.2016.16050502 }}</ref> Placental endocrine transfer to the developing fetus could be altered by the mental state of the mother, due to affected [[glucocorticoid]] transfer across the placenta.<ref name="Hoffman_2016" />

=== Thyroid ===

Line 44:

== Toxins ==

Toxins such as alcohol, tobacco and certain drugs exposed to the baby during their development are thought to contribute to foetalfetal programming, especially via alterations to the HPA axis.<ref name="Bekdash_2014">{{cite journal | vauthors = Bekdash R, Zhang C, Sarkar D | title = Fetal alcohol programming of hypothalamic proopiomelanocortin system by epigenetic mechanisms and later life vulnerability to stress | journal = Alcoholism, Clinical and Experimental Research | volume = 38 | issue = 9 | pages = 2323–30 | date = September 2014 | pmid = 25069392 | pmc = 4177357 | doi = 10.1111/acer.12497 }}</ref> Especially if exposed to during a critical window of foetalfetal development, this is thought to exert most consequence for the foetusfetus.<ref name="Bekdash_2014" />

=== Alcohol ===

Prenatal and/or early postnatal exposure to alcohol (ethanol) has been found to exert negative effects on child neuroendocrine and behaviouralbehavioral factors.<ref name="Weinberg_2008">{{cite journal | vauthors = Weinberg J, Sliwowska JH, Lan N, Hellemans KG | title = Prenatal alcohol exposure: foetal programming, the hypothalamic-pituitary-adrenal axis and sex differences in outcome | journal = Journal of Neuroendocrinology | volume = 20 | issue = 4 | pages = 470–88 | date = April 2008 | pmid = 18266938 | doi = 10.1111/j.1365-2826.2008.01669.x }}</ref> Alcohol passes through the placenta, through ingestion by the mother during her pregnancy, and is accessed by the baby in utero.<ref name="Weinberg_2008" /> the changes posed to the foetusfetus by ethanol exposure may significantly effect growth and development; these disorders constitute foetalfetal alcohol spectrum disorders (FASD).<ref name="Weinberg_2008" /> The exact interactions between ethanol and the developing foetusfetus are complex and largely uncertain, however there are thought to be both direct and indirect effects on a developing baby as it develops.<ref name="Weinberg_2008" /> Predominant effects are thought to be the foetusfetus's endocrine, metabolic and physiological functions.<ref name="Weinberg_2008" />

=== Smoking ===

The negative consequences of [[smoking]] are well-known, although the consequences may be even more apparent during pregnancy.<ref name="Suter_2013" /> Exposure to tobacco smoke during pregnancy, commonly known as ''in utero'' maternal tobacco smoke exposure (MTSE), can contribute to the different response of babies of smoking mothers.<ref name="Suter_2013" /> About 20% of mothers smoke whilst pregnant and this is associated with increased risk of complications, for example, preterm birth, decreased foetalfetal growth leading to decreased birth weight, and impaired lung development of the baby whilst they develop in the womb.<ref name="Suter_2013" />

=== Drugs ===

There is evidence for pharmacological programming during the first trimester: foetalfetal programming.<ref name="Bayliss_2002">{{cite journal | vauthors = Bayliss H, Churchill D, Beevers M, Beevers DG | title = Anti-hypertensive drugs in pregnancy and fetal growth: evidence for "pharmacological programming" in the first trimester? | journal = Hypertension in Pregnancy | volume = 21 | issue = 2 | pages = 161–74 | date = January 2002 | pmid = 12175444 | doi = 10.1081/prg-120013785 }}</ref> One such drug type suspected to influence the developing baby are anti-hypertensive drugs used during pregnancy.<ref name="Bayliss_2002" /> Pre-eclampsia (a conditional of hypertension during pregnancy), is a serious problems for proportion of pregnant mothers and can predispose the mother to a variety you complications including increased risk of mortality and problems during parturition.<ref name="Bayliss_2002" />

== References ==