3.4 Developmental Origins of Health and Disease
The Developmental Origins of Health and Disease
Epigenetic changes begin before you are born. All your cells have the same genes but look and act differently. As you grow and develop, epigenetics helps determine which function a cell will have. For example, it may become a heart cell, nerve cell, muscle cell, or skin cell.
EXAMPLE: Nerve cell and muscle cell. Your nerve cells and muscle cells have the same DNA, but they work differently. A nerve cell transports information to other cells in your body. A muscle cell has a structure that aids in your body’s ability to move. Epigenetics allows the muscle cell to turn on genes to make proteins important for its job and turn off genes important for a nerve cell’s job.
The developmental origins of health and disease (DOHaD) paradigm, rooted in the 1980s work of Barker, underscores the critical role of the intrauterine environment in shaping fetal development and influencing health outcomes across generations. The concept of “programming” was initially proposed by Dörner in 1974, who explored how early life exposures, including hormones and neurotransmitters, affect neurodevelopment and adult disease (Koletzko, 2005). Although Dörner suggested gene-environment interactions early on, empirical support emerged only with advances in epigenetics. In 1991, Lucas coined the term “developmental programming” (Lucas, 1991).
Read
Padmanabhan, V., Cardoso, R. C., Puttabyatappa, M. (2016). Developmental programming, a pathway to disease. Endocrinology, 157(4), 1328–1340. https://doi.org/10.1210/en.2016-1003
Concept in Action
Watch Developmental origins of health and diseases (DOHaD) (3 mins) on YouTube.
Video source: Demystifying Medicine McMaster. (2016, April 27). Developmental origins of health and disease (DOHaD) [Video]. YouTube. https://www.youtube.com/watch?v=MDjBNlPyqvs
What are critical periods of development?
In pregnancy, each part of the fetus’ body forms during a specific time. This specific time is called the “critical period of development” for that body part. During this critical time of development, the body can be very sensitive to exposures. Examples of exposures may include medications, alcohol, infections, health conditions, or other substances.
Critical Periods of Development – Fact Sheet
Access an HTML version of this fact sheet on the NIH Bookself.
Source: Critical Periods of Development – Mother to Baby Fact Sheet by Organization of Teratology Information Specialists (OTIS), CC BY-NC-ND 3.0.
Does the chance for different types of birth defects change during pregnancy?
Every pregnancy starts out with a 3-5% chance of having a birth defect. This is called the background risk. If an exposure can increase the chance for birth defects, the chance depends on what body part is developing at the time of exposure. Once a body part has formed, it is no longer at risk to develop major birth defects. Some exposures could still affect a body part’s growth and/or function even after that body part has formed.
The chart in the Critical Periods of Development – Fact Sheet (above) shows the critical periods of development for different parts of the body. The chart starts from the time of conception when the egg and sperm join. The weeks listed on the chart are the “embryonic age” or “fetal age” of a pregnancy. This is different from a common way of dating a pregnancy called “gestational age.” Gestational age begins with the first day of a person’s last menstrual period. This day is usually about two weeks before a pregnancy is conceived. For example, 12 gestational weeks (since the first day of your last period) is the same as 10 fetal weeks (since the first day of conception).
Birth defects are physical or structural differences that may change how a body part looks and/or works. Birth defects are typically classified as “major” if they cause significant medical problems and may need surgery or other treatment. Heart defects, spina bifida, and clubfeet are examples of major birth defects. The solid bars on the chart show when each body part is most sensitive to harmful exposures and at risk for major birth defects.
“Minor” birth defects by themselves do not cause significant medical problems and usually do not require treatment or surgery. Minor birth defects can also be variations of typical development. Wide-set eyes and large ears are examples of minor birth defects. The striped bars show periods when the body parts are still at risk of developing minor birth defects and functional defects. “Functional defects” change how a part of the body works without changing how it looks. Intellectual disability and hearing loss are both examples of functional defects.
The chart also shows the location of the most common birth defects that can occur during each week. In general, major birth defects of the body and internal organs are more likely to happen between 3 to 12 embryonic/fetal weeks. This is the same as 5 to 14 gestational weeks (weeks since the first day of your last period). This is also referred to as the first trimester. Minor defects and functional defects, including those affecting how the brain works, can also occur later in pregnancy.
There are certain exposures that are known to contribute to fetal abnormalities, called teratogens, which include certain medications, illegal and legal substances, chemicals, and certain maternal infections. It is also known that environmental exposures can cause epigenetic changes and there is a greater likelihood of an impact on the epigenome during critical periods.
The First 1000 days
Researchers have learned that the first 1000 days of a child’s life are critical to a child’s optimal growth and development. How did they come up with the number 1000?
Concept in Action – the First 1000 Days
The First 1000 Days (text version)
Why is this period important and what can be done to optimize a child’s well-being in the first 1000 days?
Activity source: created by Andrea Gretchev, CC BY-NC 4.0 except where otherwise noted.
Attribution & References
Except where otherwise noted, this page is created by Andrea Gretchev and licensed under CC BY-NC 4.0.
- Critical Periods of Development – Mother to Baby Fact Sheet by Organization of Teratology Information Specialists (OTIS), CC BY-NC-ND 3.0.
References
Koletzko, B. (2005), Developmental origins of adult disease: Barker’s or Dörner’s hypothesis? American Journal of Human Biology, 17, 381-382. https://doi.org/10.1002/ajhb.20139
Lucas, A. (1991). Programming by early nutrition in man. Ciba Foundation Symposium, 156, 38-50. Cited in: Padmanabhan, V., Cardoso, R.C., & Puttabyatappa, M. (2016). Developmental programming, a pathway to disease. Endocrinology, 157(4), 1328-1340. https://doi.org/10.1210/en.2016-1003
Organization of Teratology Information Specialists (OTIS). (2023, February). Critical periods of development, mother to baby | Fact sheets. https://www.ncbi.nlm.nih.gov/books/NBK582659/ CC BY-NC-ND 3.0.
