Researchers found that pregnant women who later have babies that are smaller than expected have lower levels of a hormone called metastin (kisspeptin‑10) in their blood during the first trimester, while another hormone, beta‑hCG, stays the same.

To investigate whether pregnancies with small for gestational age (SGA) neonates, defined as customized birth weight below the 10th centile, are associated with altered levels of metastin in maternal plasma in the first trimester. Maternal blood was obtained between 8 and 14 weeks of pregnancy. Levels of metastin were measured in pregnancies with (n = 31) or without SGA-neonates (n = 31), matched for gestational age at venipuncture. Measurement of beta-hCG was included to study the influence of gestational age and placental volume on plasma levels of the measured markers. Metastin was significantly lower in SGA-pregnancies compared to an equal number of matched uneventful pregnancies (metastin: 1376 +/- 1317 pmol/L vs 2035 +/- 1260 pmol/L, p = 0.035; mean +/- standard deviation). beta-hCG levels were not different. Metastin is significantly lower in maternal plasma in the first trimester, in pregnancies with SGA-neonates. It might therefore be used in combination with other markers for risk estimation of growth impairment in the first trimester.