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Is my morning sickness worse because of genetics?

Morning Sickness Genetic

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If you’ve ever had or known anyone who has experienced morning sickness in pregnancy, you’ll know that it’s more like “all day sickness” and can strike at the most inopportune times. Around 70%-80% of women experience nausea and vomiting in pregnancy (NVP), typically in the first trimester. (R) Not everyone has to deal with morning sickness, though, with some studies in siblings suggesting a genetic predisposition for morning sickness.

After further research, lo and behold, new data suggests that at least two genes are associated with extreme nausea and vomiting in pregnancy (known as hyperemesis gravidarum, or HG).

This post will discuss how and why morning sickness happens, general risk factors for morning sickness, the genetic links to more severe morning sickness, and natural remedies that may aid in reducing morning sickness symptoms, including prenatal supplements.

Why does morning sickness happen?

The truth is that nobody really knows for sure. Morning sickness may be related to changes in hormones, such as human chorionic gonadotrophin (hCG), thyroxine, and estrogen in pregnancy. It may also be linked to fluctuations in blood glucose related to changes in food consumption and anabolic hormones such as insulin and insulin-like growth factor-1 (IGF-1). It’s also possible that this common symptom is a mechanism evolved to protect the unborn fetus from potential toxins. Indeed, there is some evidence that NVP may reduce the risk of having a miscarriage, delivering preterm, or having a low birth-weight baby. (R)

Unfortunately, for up to 2% of women, morning sickness is not just unpleasant and annoying to deal with, it can be so severe as to necessitate medical intervention, including feeding tubes and intravenous fluids. And, in some cases, HG (severe morning sickness) can lead to miscarriage; birth defects; electrolyte imbalance; dangerous weight loss; dehydration; nutrient deficiencies; and weakness, fatigue, and depression. (R) (R) (R)

Who is more likely to get morning sickness?

Morning sickness might be more likely to occur in the following situations (R):

  • Where the fetus is female;
  • Multiple pregnancy (twins, triplets, etc.);
  • Where there is a family history or personal history of morning sickness;
  • In individuals with a high body mass index (BMI) or who are overweight or obese;
  • In individuals with a history of digestive issues and/or motion sickness;
  • In individuals with a history of migraines, headaches, and/or dizziness;
  • In younger birth parents; or
  • In people with a history of nausea when taking estrogen-containing contraceptives.

NVP is also more likely in people living in western countries and in an urban environment (although this may be down to differences in reporting rather than incidence). It is also more likely in people of Caucasian and Middle Eastern descent, but is rarer in people of African descent; First Nations, Inuit, and Native American people; and most Asian populations. (R)

Morning sickness is also significantly more likely in a person whose sister or mother had hyperemesis gravidarum, leading geneticists to investigate the link between NVP and genes. (R)

Is hyperemesis gravidarum genetic?

A study published recently in the journal Nature Communications revealed that two genes, GDF15 and IGFBP7, are associated with a higher risk of hyperemesis gravidarum. These genes code for placental development and influence appetite regulation, and have already been associated with cachexia, a condition characterized by loss of appetite and muscle wasting. (R)

A common variation in the GDF15 and IGFBP7 genes seems to increase the likelihood of HG, but only in some women, suggesting environmental influences and a role for nutriepigenetics, perhaps. Indeed, greater expression and activity of these genes, indicated by higher levels of specific proteins in the blood, has been found in people hospitalized for HG, compared to people with less severe or no morning sickness. (R)

Interestingly, morning sickness peaks at weeks 9-16, which is when the placenta and fetus are most vulnerable to damage from toxins, including ingested toxins from food and water. (R)

Other studies have noted that genes involved in the production of the hormone hCG and its receptors may also play a role in morning sickness. (R)

Reducing your risk of morning sickness

A gene-based therapy for HG may not result from research focused on morning sickness itself. Instead, researchers looking at cachexia, which is responsible for a significant number of cancer-related deaths (R), may uncover a useful therapy first.

In the meantime, to reduce your risk of morning sickness it can help to:

  • Achieve and maintain a healthy body weight prior to pregnancy.
  • Manage blood sugar levels by eating healthy meals and snacks throughout the day.
  • Getting regular exercise to support insulin sensitivity and to maintain a healthy body weight.
  • Avoid foods that trigger nausea (some common culprits include meat, seafood, and leftovers, which are more likely to contain harmful chemicals, parasites, and bacteria).
  • Avoid alcohol and caffeine (wean yourself off caffeine prior to pregnancy if possible; Amber wrote a great post on ways to reduce your caffeine intake that you can look at for more information, including switching to healthy decaf teas).

Some people find that when they become pregnant, even their favourite fruits and vegetables suddenly have too strong a taste. Broccoli, mushrooms, and bitter greens are common triggers for nausea, so don’t force yourself to eat these just because they’re good for you! Instead, eat plenty of milder tasting foods such as squash, carrots, peppers, legumes, and whole grains.

Because many people find that they lose their appetite for animal products in pregnancy, this can lead to inadequate protein intake, especially because pregnancy can increase your protein requirements by almost as much as 100% by some estimations. (R) Be sure to top up your protein intake with legumes, nuts, pulses, seeds, and even a plant-based protein powder if that’s easier.

See also: 10 things I learned going vegan for a week

Natural remedies to treat morning sickness

Ginger is probably the most well-known remedy for NVP, and for good reason. A large body of research supports the use of fresh ginger, ginger tea, and ginger capsules for relieving nausea and soothing the digestive tract. In one single-blind clinical trial study, 67 pregnant women were evaluated for treatment of their nausea symptoms. An experimental group received 250mg of ginger capsules for four days, while the control group received a placebo. Those who took the ginger capsules fared much better than the placebo group in both improvement of nausea symptoms (85% vs. 56%) and decrease in vomiting (50% vs. 9%). The study concluded that practitioners may recommend 1,000mg of ginger daily to pregnant women, but it’s important for women to consult with their doctor before taking any supplements or medication. (R)

Supporting better blood glucose regulation can also keep morning sickness in check. As such, it can help to eat meals and snacks that provide protein, fats, and fibre alongside a complex, starchy carbohydrate. This helps to avoid large fluctuations in blood sugar. Be sure not to skip breakfast or any other meals, even if this means eating something simple like plain crackers or toast. Regular exercise also helps support blood sugar regulation by improving insulin sensitivity.

A note on prenatal supplements and nausea

Prenatal supplements can help ensure a good intake of folate, iron, omega-3 DHA (docosahexanoic acid), and other vital nutrients needed during this period of rapid growth. Unfortunately, some people experience nausea when taking prenatal formulas. If this is the case for you, try taking supplements before bedtime with a small snack, rather than with breakfast.

Most prenatal supplements will include some vitamin B6, which has been shown to help reduce nausea and vomiting in pregnancy. (R) In a randomized, double-blind clinical trial comparing the effects of ginger (25omg) and vitamin B6 (40mg), along with a sugar placebo taken over four days, 120 pregnant women saw about a 61% reduction in symptoms after each supplement treatment compared to a 43% reduction after placebo alone. However, those in the placebo group also discontinued their treatment and began using other methods after their severity of symptoms did not subside. Those taking ginger capsules, however, did have a slightly higher risk of stomachache, heartburn, and increased nausea. (R)

It’s important not to take too much vitamin B6, so check the level of your prenatal vitamin and talk to your health care practitioner about topping out at around 25mg three times per day to help with nausea. Do not take additional vitamin B6 without first consulting with a medical professional, and don’t take more than he or she recommends.

Morning sickness supplement comparison

SupplementFormulaQuantitySafety warning
Solaray Ginger Root Extract250mg ginger root extract at 5% gingerols, 100mg ginger60 capsulesPregnant women should consult their healthcare provider prior to use
Pure Science Ginger Root Capsules700mg ginger root extract at 5% gingerols50 capsulesPregnant women should consult their healthcare provider prior to use
Pure Encapsulations B-Complex Plus16.7mg Vitamin B6, 100mg thiamin, 108mg niacin, 12.7mg riboflavin, 400mcg folate, 400mcg Vitamin B12, 400mcg biotin, 100mg pantothenic acid120 capsulesDo not overdose Vitamin B6, and be sure to consult with your healthcare provider before taking this product if pregnant
Thorne Research Basic B Complex10mg Vitamin B6, 110mg thiamin, 140mg niacin, 10mg riboflavin, 400mcg folate, 400mcg Vitamin B12, 400mcg biotin, 110mg pantothenic acid60 capsulesDo not overdose Vitamin B6, and be sure to consult with your healthcare provider before taking this product if pregnant

Takeaways

Remember that for most women, morning sickness eases up considerably at around 14-16 weeks and is much less common in second pregnancies! Still, there are various ways to reduce the symptoms of morning sickness, including natural remedies like ginger and tea and making sure to stay on top of taking your prenatal supplements. Individuals using anticoagulants should talk to their physician before taking ginger (or any natural health products), as it may interfere with blood clotting. (R)

If you’re experiencing severe nausea and vomiting, or if it persists well into your second trimester, talk to your midwife, physician, or other health care practitioner for advice. And again, speak to your OB/GYN before taking any supplements or other medication to ensure it’s safe for your particular pregnancy.

Do you have any tried-and-true methods for relieving morning sickness? Let us know in the comments!

Leigh Matthews

Leigh Matthews, BA Hons, H.Dip. NT, is a health and wellness writer for Gene Food specializing in plant-based nutrition. Read her full bio here.

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