Nutrient Requirements in Twin Pregnancies
Researching this particular topic “Nutrition Requirements in Twin Pregnancies” has not yielded a ton of answers unfortunately - but that’s not surprising when it comes to women’s health. There is guidance about nutritional recommendations for singleton pregnancies (when someone is pregnant with one baby), but there’s gap in guidelines when it comes to multiples.
Nevertheless, there is some research to show that additional amounts of certain nutrients are needed in pregnancy.
Rate of twin pregnancies
The rate of twin pregnancies have increased over the last 30 years due to a few reasons:
Use of assisted reproductive technologies like IVF (in my experience, some of my patients have two embryos transferred based on how their retrieval went and their age)
Obesity (BMI equal to and over 30) leads to an 40% increase in twin pregnancies
Notable adverse pregnancy outcomes & twin pregnancy
As the rate of twin pregnancy has increased, so has the risk of adverse pregnancy outcomes. These include:
Hypertension and preeclampsia
Iron-deficiency anemia
Preterm birth
Important Nutrients in Twin Pregnancies
Folic Acid
Folic acid is important in the prevention of neural tube defects. The neural tube closes around 4 weeks after conception (once the sperm meets the egg), which is the rationale behind supplementing with folic acid 3 months before conception happens (but really supplementing with folic acid if you’re sexually active and of reproductive age). Research shows that neural tube defects are often higher in twin pregnancies (2.3 out of 1000 births).
Folate (commonly seen as methylated folate), unfortunately does not have the same breadth of evidence as folic acid when it comes to the prevention of neural tube defects (sorry to be the bearer of bad news!).
Alberta Health Services (AHS) notes a recommendation of a higher amount of folate than is usually recommended in a singleton pregnancy (which is often 0.4mg).
Iron
Iron is the most common nutritional deficiency in women - mainly due to menses. When most people enter pregnancy they are already deficient in iron, and level continues to decrease as blood volume increases, red blood count increases, and other maternal needs.
Ferritin, the marker which will tell you if an iron-deficiency is present, is commonly measured with beta-hCG (and may be artificially elevated at that point) and again around 24-28 weeks with the gestational diabetes test.
In pregnancy specifically, iron-deficiency anemia (low ferritin + hemoglobin) increases the risk of pre-term birth and low birth weight. Therefore, if we can assess someone’s stores by the end of the first trimester (and possibly supplement with iron), it may help to reduce these risks.
Vitamin D
In my experience, many of my pregnant clients are vitamin D deficient. A common factor is that we live in Canada - as of this article, we spent the last week in Toronto with long sleeves and pants at the end of May!
Vitamin D is important in pregnancy as low levels are associated with:
Increased body pain
Placental complications
Small for gestational age babies
Preterm birth
Low birth weight babies
Vitamin D is one of those vitamins that I commonly encourage patients to test, especially since a vitamin D deficiency in the postpartum is linked to an increased risk of postpartum depression - a serious condition that individuals with a twin pregnancy are already at risk of.
Calcium
This might be an obvious one, more calcium is needed because two skeletons are being formed instead of one. AHS recommends that total calcium intake per day should be around 2000-2500mg.
I commonly have clients use a calcium calculator to assess how much calcium they are getting from their diet, so we can determine how much to supplement with.
DHA
DHA (docosahexaenoic acid) is an omega-3 fatty acid that may also reduce the risk of preterm birth and low birth weight. In addition, it helps with fetal nervous system and eye development.
Supplementation should be considered in people who don’t routinely eat fish, or are vegan or vegetarian.
Special Considerations
For pregnant individuals following a specific diet (ex. vegan and vegetarian), assessing the levels of most of these nutrients (via blood work) will provide the most information to determine if additional supplementation is needed.
It’s been found that supplementing through diet in the hopes of raising certain levels (ex. eating 3 cups of spinach or a steak to increase ferritin; or spending more time outside to increase vitamin D), while helpful, may not be enough to correct a deficiency.
Next Steps
If you are pregnant with twins, consider visiting a naturopathic doctor to determine if you need extra supplementation beyond what’s in your prenatal, and maybe even doing some blood work!