Throughout pregnancy, growing babies require an adequate supply of carnitine for normal growth and development. Because research shows that blood carnitine levels steadily decline throughout pregnancy, some scientists have wondered if certain women might be at higher risk for developing a low carnitine status.^1,2 And, since deficient carnitine levels have been linked to unfavorable outcomes such as preterm birth and low birth weight, increasing dietary carnitine intake may be necessary for women with reduced carnitine levels.^3,4 In this article, we will discuss the reasons why carnitine levels decrease during pregnancy, carnitine’s role in prenatal development, and how to maintain an adequate carnitine status during pregnancy.

Why do carnitine levels decrease during pregnancy?

During the first trimester, many women experience “morning sickness” (nausea and vomiting that can last all day), which may significantly reduce appetite and nutrient intake.⁵ Indeed, morning sickness may lead to various nutritional deficiencies, especially for women who started the pregnancy with a low nutritional status.⁵ The most common micronutrient deficiency experienced during pregnancy is iron-deficient anemia, which affects about 40 percent of pregnant women in the US.⁶ Because carnitine synthesis is partially reliant on iron status, this means a lot of women with low iron availability may not be able to make carnitine readily as needed.^7,8 Furthermore, research shows that pregnant women carrying excessive weight are more likely to be iron-deficient and have lower carnitine levels compared to pregnant women of normal weight.^9,10 A final factor worth mentioning is that pregnancy-related changes in kidney function can also lead to accelerated carnitine loss during urination.¹¹

How vital is carnitine for the mother and baby?

Throughout the prenatal period, babies use substantial amounts of fats and carnitine for energy production, growth, and development.¹² While in the womb, babies must also store adequate amounts of carnitine in the liver and muscle tissue to help ensure survival after birth.¹³ This is because infants rely heavily on the energy produced from ketones (byproducts from fats that can be used for energy) following birth – an energy-intensive process that requires high amounts of carnitine.¹⁴ By nature’s design, infants can also get carnitine and ketones from their mother’s breastmilk, which should ideally contain high amounts of carnitine to support the critical brain growth and development occurring during infancy.¹⁵ Also, carnitine can be used to convert ALA (an essential omega-3 fatty acid precursor) into DHA within cell membranes. DHA is an important nutrient for brain health across the lifespan, but especially important for developing neurological structures during the first few years of life.^16,17

Adequate carnitine status is also critical for the mother, as she needs sufficient amounts to support her energy metabolism during pregnancy, and sufficient amounts to pass along to her baby if she chooses to breastfeed.¹⁸ Interestingly, compared to non-pregnant women, pregnant women experience dramatic increases in ketone production when fasting.¹⁸ Because carnitine is required to support ketone production, it’s important that the mother has ample amounts of carnitine. 

How can I maintain an adequate carnitine status during pregnancy?

As discussed, many women experience iron-deficient anemia during pregnancy, which can impair their ability to produce carnitine. Fortunately, when iron status is adequate and enough protein is consumed, most women are able to synthesize a sufficient amount of carnitine from the amino acids lysine and methionine to meet their needs during pregnancy.¹⁹ Dietary methods for supporting a healthy carnitine status include eating foods high in carnitine, such as meat, poultry, fish, and dairy products. Animal protein sources are particularly helpful, as they contain highly absorbable iron which can also be used for carnitine synthesis.²⁰ Unfortunately, certain individuals (such as those carrying excess weight, those experiencing extreme morning sickness, and those following a vegan/vegetarian lifestyle) may be at risk of low carnitine status.³

Conclusion

Throughout pregnancy, high carnitine demands cause a steady decline in women’s blood carnitine levels. This is because, in addition to her increased production of ketones, carnitine is being shuttled to the growing baby, who must accumulate sufficient amounts during pregnancy to help meet the energy demands needed after birth. Considering that several health factors can contribute to a reduced carnitine status during pregnancy, we recommend that all expecting mothers talk to their doctors about whether they are getting enough carnitine, or whether additional carnitine supplementation is needed.