Better B6 status linked to better pregnancy outcomes
conception rates and reduce the odds of losing the baby during
early pregnancy, suggests new research.
If the results, published in the American Journal of Epidemiology, are repeated in more studies in other populations around the world, it may see vitamin B6 force an extension of the current "Big 3" of pregnancy nutrition: folic acid, calcium with vitamin D, and omega-3 fatty acids.
"We found that poor preconception vitamin B6 status was associated with increased risk of early pregnancy loss and reduced probabilities of conception and clinical pregnancy in a prospective cohort of young Chinese women," wrote lead author Alayne Ronnenberg from the University of Massachusetts Amherst.
"This study underscores the potential importance of micronutrient status at the time of conception on pregnancy outcome."
The researchers, from U of M Amherst, University of Illinois, Harvard Medical School, Anhui Medical University (China), Northwestern University, and Children's Memorial Hospital and Children's Memorial Research Center, looked at the B vitamin status (folate, B6 and B12) of 364 women (average age 24.9, average BMI 19.8 kg per sq. m) working in the textile industry in Anqing, China.
The women were included if they conceived at least once during prospective observation (1996-1998) and provided daily urine samples over a 12-month period.
The urine was tested for human chorionic gonadatropin (hCG) to detect conception and early pregnancy loss.
Ronnenberg and co-workers report that women with vitamin B6 levels above 38.3 nanomoles per litre increased the odds of conception by 120 per cent, and halved the odds for early pregnancy loss if levels were above 46.4 nanomoles per litre.
They also report that sufficient levels of B6, defined as levels above 30 nanomoles per litre, improved the odds of conception by 40 per cent and lowered the odds for early pregnancy loss by 30 per cent, compared to women with B6 deficiency.
No relationship was observed between normal vitamin B12 or folate status and conception or loss odds.
"The physiology underlying the relation between low vitamin B6 status and early pregnancy loss is unknown, although several biologically plausible mechanisms are possible," wrote Ronnenberg.
"Vitamin B6-dependent coenzymes participate in over 100 reactions involved in the metabolism of amino acids, lipids, nucleic acids, and glycogen.
Vitamin B6 deficiency has also been associated with impairment of enzymes involved in the structural integrity of arterial walls, which could affect implantation and early placental development."
The results should be treated with caution, and further research is needed to support the observations and test if similar results are obtained in other populations.
"Taken in their entirety [with other studies], these observations suggest that maternal vitamin B6 status may influence reproductive events throughout the entire course of pregnancy, from the time of conception through delivery," wrote the researchers.
Source: American Journal of Epidemiology Volume 166, Number 3, Pages 304-312; doi:10.1093/aje/kwm078 "Preconception B-Vitamin and Homocysteine Status, Conception, and Early Pregnancy Loss" Authors: A.G. Ronnenberg, S.A. Venners, X. Xu, C. Chen, L. Wang, W. Guang, A. Huang and X. Wang
