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Why It's Important to Eat Healthy Before You Get Pregnant: And Other Preconception Lifestyle Changes

Updated: Jan 6, 2021

Early Critical Windows Occur Before You Know You Are Pregnant

Critical windows are the windows of time where specific organ systems are developing and are most sensitive to being harmed by environmental factors. Environmental factors can be things we ingest that are harmful like alcohol, drugs, or other toxins or can be things we need for proper development like nutrients. Mom’s hormones, and other biological factors are also environmental factors. Hormone levels are a main environmental factor that influences milestone development. Things like stress, lack of sleep, medications, drugs and what we eat impact our hormone levels.

Many critical milestones occur early in pregnancy before a woman may know that she is pregnant. Therefore, you could be doing something that could harm your baby before you even know you are pregnant.

Windows of Susceptibility

Due to the different timing of organ development, an exposure to the same toxin at the same dose can have different effects and to differing degrees. The first two weeks of pregnancy the fertilized egg begins dividing and implants in the uterine wall. During the next approximately 3-8 weeks (the baby is considered an embryo at this time) the dividing cells start forming the precursors to the different organs. This period is particularly sensitive to exposures that can cause miscarriage or birth defects. The next 9-40 weeks (baby is now considered a fetus) the organs continue growing and developing and are still susceptible to harm from environmental exposure.

An example of a drug that caused different issues at various times of exposure is the drug Thalomide, which was used in the 1950’s to treat a variety of ailments, including nausea. The company marketed it as being safe for use during pregnancy. It was available over the counter in many countries, including the UK (it was never approved for use in the US).

It took 5 years for the link to be made to Thalomide and birth defects. This was partly due to the wide range of birth defects seen. It caused devastating effects from day 20-37 of pregnancy but did not seem to cause harm after day 37. Depending on which day the exposure occurred, a different part of the body was impacted, including hearing, eyesight, limbs and internal organs, and the brain. Visit to learn more about the history of Thalomide and see this chart to see what organ systems it affected based on the day taken.

During critical windows, your baby is also susceptible to a lack of nutrients. Cells are dividing at a rapid rate all through pregnancy and this takes a lot of energy. The body needs a variety of vitamins and minerals to produce energy, particularly the B-vitamins. An example of a lack of a nutrient causing an issue during a critical window is that a lack of folate increases the risk of neural tube defects. The neural tube is the precursor to the spine and brain. If it does not close by about day 21 serious birth defects can occur. The most common ones are spina bifida and anencephaly. Supplementation with folate prevents most neural tube defects. The key, though, is starting supplementation in time for this critical window, so that the body has enough folate during the first three weeks of pregnancy. This means starting supplementation before pregnancy (note, certain medications and alcohol interfere with folate absorption).

Medline Plus has a summary of neural tube defects.

It Can Take Weeks or Months to Prepare the Body for Pregnancy

It may take weeks or months for the body to completely flush out toxins from medication or drugs and it may take weeks or months to build up important stores of nutrients, both of which are important to the healthy development of a baby. This is particularly true between pregnancies, as the body needs time to replenish the nutrients a baby uses during development in utero and after pregnancy if breastfeeding. Mom also needs time and nutrients to heal from pregnancy and labor.

If you have pre-existing conditions, there may also be nutritional deficiencies or imbalances that need to be addressed prior to getting pregnant. Some of these can take time. For example, women with Type 2 Diabetes will want to make sure their blood sugar is well under control. Uncontrolled blood sugar can be dangerous for mom and baby. Plus, it can impact fertility.

Uterine Lining Health

Health of the uterine lining is critical for implantation of the embryo and for the developing placenta. Therefore, there are things we can do prior to getting pregnant to support the development of a healthy uterine lining. Things like moderate exercise and reducing caffeine intake can help with circulation to the uterus. Also, some alternative modalities like acupuncture and massage can be helpful. Addressing insulin resistance can also help with balancing the hormones that regulate the menstrual cycle.

Health of Eggs and Sperm Impacted by What we do in the Weeks and Months and Years Prior to Conception

Women are born with their lifetime supply of eggs. These eggs are immature until right before fertilization. Within the ovaries are follicles, which contain eggs. Each month many eggs are chosen to begin the maturation process. The maturation process occurs during the first part of a woman’s cycle and ends with one egg (usually) being released for fertilization. This is ovulation. Since the egg cell finishes maturing each month there is the potential to impact the quality of that egg during that time.

Men continuously produce sperm, but it takes about three months to produce sperm. Therefore, the actions a man takes everyday impact the quality of his future sperm.

Hormones and other molecules (like cAMP/cGMP) influence egg maturation and release and therefore the quality of the eggs. Similarly, hormones play an important role in sperm production. As we age there is more likely to be genetic errors when copying DNA during cell division. Quality sleep, proper nutrition (particularly nutrition that balances blood sugar), managing stress and exercise all impact hormone regulation.

What We Do Pre-conception and During Pregnancy Effects Health of Our Babies and Future Descendants for Life

Cells need to know what to do with DNA/RNA. They need a way to know which genes should be turned on or off and how much they should be turned on. DNA/RNA is marked with tags (epigentic markers or tags) that tell the cells which genes should be expressed. This is a complex topic that scientists are just beginning to understand. I will be writing a future post on this to help explain how epigenetics works and why it is so important. But for now, the key take away is that these markers on the DNA/RNA are altered by things that we do like smoking, how we eat, exercise and stress. And there is some evidence that these markers can be passed to our children and their children, etc. Some epigenetic markers are passed to the next generation and many are added during pregnancy based on stressors in the environment. These changes impact the health of your baby for life. They can impact learning and risk of chronic disease later in life.

This becomes particularly important for growing a baby because those markers tell the baby’s cells what to become (ie the heart versus liver versus muscle), but also program those cells for the future. Therefore, what we do throughout our lives has the potential to impact our baby’s health. In particular, what we do preconception (men and women) and what we do during pregnancy affects these markers. Infancy and early childhood are also critical times for adding/removing genetic markers, so we as parents have a lot of control concerning our baby’s health during this time (often referred to as the first 1000 days).

In summary, the preconception window is a time of opportunity. It is a time to make choices that can give your child a foundation of health (physical, mental, and emotional). This does not mean that you need to be perfect and that if your child has challenges that it is your fault. We are still learning so much on this front, that I think what we can do is make choices that fit with our lives. Perhaps for you it is giving up caffeine and losing ten pounds. For another person it may be only drinking one cup of tea a day and gaining ten pounds. The idea is that we can look at our lives and find areas where we can make improvements. First, we start with the low hanging fruit, the changes that prevent birth defects and immediate risk to a pregnancy. Then we can look at our lives and see where it makes the most sense to make changes that may have subtle but significant impacts. Reducing toxins in our environment (either from cleaning supplies or plastics), reducing coffee, eating more fruits and vegetables, etc.

Everyone’s journey will look different, but the idea is that you are making changes that will give your children, and their children, an improved foundation for health, learning and over all well-being.

In part two of this post I will discuss lifestyle changes to implement preconception. In the mean time sign up for updates and receive a free three day Pre-conception Meal Plan!

Citations and Additonal Resources

Hughes, Virginia. Epigentics: The Sins of the Father

Further Resources on Epigentics

Centers for Disease Control. What is Epigentics? Good summary of epigentics with some examples.

Scishow. Epigentics Episode. Fun ten minute video explaining epigentics.


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