Low Amniotic fluid rubidium concentration during mid-pregnancy linked to third-trimester lower birthweight

Amniotic fluid rubidium concentration predicts appropriate for gestational age birthweight and may classify newborn birthweight. Low Rb concentrations in mid-pregnancy are associated with a lower third-trimester birthweight percentile. This could be a valuable tool for early predicting pregnancy outcomes.

This study, “Amniotic fluid rubidium concentration association with newborn birthweight: A maternal-neonatal pilot study,” is led by Yaniv S. Ovadia et al. and colleagues.

Human tissues contain rubidium. Animal studies show an association between rubidium deficiency in the maternal diet and lower newborn birthweight. More data from in vivo studies must be available to determine its biological functions, and its possible role in neonatal birthweight still needs to be discovered. An animal study indicated a correlation between rubidium deficiency in the maternal diet and lower newborn birthweight.

This study evaluated rubidium levels in amniotic fluid during the second trimester of low-risk pregnancies. It examined associations between these levels and several outcomes, including newborn birthweight, small, appropriate and large for gestational age, and preterm vs. term births in uncomplicated pregnancies.

This study explored the possible association between the rubidium concentration in the amniotic fluid during the second trimester and the birthweight percentile in the third trimester. The amniotic fluid was collected from a median gestational age of 19 weeks to determine the rubidium concentration. The study also obtained maternal and newborn characteristics from participant and delivery records.

One hundred seventy-three pregnant women were screened, and 99 amniotic fluid samples were evaluated. Further results could be assessed as follows:

The researchers discovered that the median rubidium levels in the middle of pregnancy were lower among newborns classified as small for gestational age compared to those classified as appropriate for gestational age based on their birth weight.

Amniotic fluid rubidium was identified as a significant contributing factor to appropriate for gestational age birthweight with 54% of the total contribution.

The rubidium concentration in amniotic fluid is a strong predictor of appropriate for gestational age birthweight and a potential marker for newborn birthweight classifications. Specifically, low Rb concentrations in amniotic fluid during mid-pregnancy are associated with a lower birthweight percentile in the third trimester. These findings could be a valuable tool for early identification of pregnancy outcomes. However, further investigation is necessary to explore the effects of Rb on fetal development fully.

Further reading:

https://www.ajogmfm.org/article/S2589-9333(23)00291-4/fulltext