Carnitine status of pregnant women: effect of carnitine supplementation and correlation between iron status and plasma carnitine concentration

Abstract

Background/Objectives: It has been shown that plasma carnitine concentrations markedly decline during gestation in women. The reason for this, however, is unknown. One objective of this study was to investigate the effect of carnitine supplementation on plasma carnitine concentrations in pregnant women. The second objective was to investigate the hypothesis that reduced plasma carnitine concentrations during gestation are caused by a reduced carnitine synthesis because of a diminished iron status. Subjects/Methods: Healthy pregnant women (n ¼ 26) were randomly assigned in two groups receiving either a L-carnitine supplement (500 mg L-carnitine per day as L-carnitine L-tartrate) (n ¼ 13) or placebo (n ¼ 13) from the 13th week of gestation to term. Results: In the control group, there was a marked reduction of plasma carnitine concentration from the 12th week of gestation to term. This reduction was prevented by the supplementation of carnitine. In the control group, there was a positive relationship between the parameters of iron status (mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH) and ferritin) and plasma concentration of carnitine (Po0.05). Moreover, there were inverse correlations between the concentrations of ferritin and the carnitine precursor g-butyrobetaine in plasma, and between g-butyrobetaine and carnitine in plasma (Po0.05).Conclusions: This study confirms that plasma carnitine concentrations decline in the course of pregnancy, an effect that can be prevented by the supplementation of carnitine. Data of this study, moreover, suggest that the decline of plasma carnitine concentration during pregnancy could be caused by a reduced rate of carnitine biosynthesis, possibly because of an inadequate iron status.

Enzymology of the carnitine biosynthesis pathway

“…OCTN2 is present in the human placenta and mediates fetal uptake of carnitine, but both the human fetal liver, kidney, spinal cord and placenta where also shown to synthesize carnitine (51). However, the availability of TML might be limiting as carnitine supplements have been shown to increase fetal growth in pigs (52,53) and human maternal plasma carnitine levels decrease during early pregnancy (54). Both of these findings indicate a high demand for additional carnitine during fetal development.…”

Oral l-carnitine as treatment for narcolepsy without cataplexy during pregnancy: A case report

“…Acylcarnitine serum levels were reduced during pregnancy and Lcarnitine integration in pregnant women may be safe and advantageous [5]. In addition, low L-carnitine levels were recently associated with obesity at term pregnancy, representing a significant risk factor for sleep apnea and sleepiness [10].…”

“…Therefore, a randomized placebo-controlled trial in narcolepsy patients showed the efficacy of oral L-carnitine in reducing somnolence in narcolepsy patients [4]. In addition gestation is a physiological state that leads to lower plasma carnitine concentrations and its supplementation is safe during pregnancy [5].…”

Abnormal Newborn Screening in a Healthy Infant of a Mother with Undiagnosed Medium-Chain Acyl-CoA Dehydrogenase Deficiency

“…It is well described that plasma carnitine decreases during pregnancy from the 12th week of gestation to term and may reach concentrations half the normal in healthy nonpregnant women. The decrease in total carnitine is mainly caused by a decrease in free carnitine (Schoderbeck et al 1995) and is thought to be the consequence of a reduced rate of carnitine biosynthesis, possibly because of an inadequate iron status (Keller et al 2009) or because of a low availability of precursors for carnitine (Ringseis et al 2010). Interestingly, one study reported a complete normalization of plasma carnitine one month after delivery (Marzo et al 1994), and our finding of low-normal free carnitine 16 days after delivery may reflect a partial normalization to concentrations often seen in patients with MCADD.…”