Low kisspeptin-10 predicted early pregnancy loss in a study

Researchers followed 463 pregnancies between 7 and 12 weeks, all with a confirmed heartbeat. They measured kisspeptin-10 in the blood at the start. Thirty of those pregnancies ended before 20 weeks. The women who had a loss had lower kisspeptin-10: on average 0.73 nanograms per milliliter, compared with 1.92 in women whose pregnancies continued ¹.

After adjusting for other factors, low kisspeptin-10 and higher body mass index were each independently linked to pregnancy loss ¹. The study was observational, so it cannot show that low kisspeptin-10 causes the loss. It shows an association.

A separate case-control study compared 75 women: 25 fertile, 25 with unexplained infertility, and 25 with PCOS, a condition that affects ovulation. Blood kisspeptin-10 was lowest in fertile women, higher in women with unexplained infertility, and highest in women with PCOS ².

Kisspeptin-10 also correlated with two hormones: luteinizing hormone (LH), which triggers ovulation, and anti-Müllerian hormone (AMH), a marker of ovarian egg reserve ². When used to tell fertile from infertile women, kisspeptin-10 alone had a discrimination score of 0.86, where 1.0 is perfect and 0.5 is chance. A panel of four markers, including kisspeptin-10, reached 0.93 ². This means kisspeptin-10 could help identify fertility issues, but the study was small and from a single hospital.

A mouse experiment tested kisspeptin-10 directly rather than measuring it. Female mice given the peptide produced more reproductive hormones, developed more ovarian follicles, and had better fertility outcomes ³. The effect appeared to work through three signaling proteins inside cells: PI3K, AKT, and ERK. These proteins help cells grow and survive ³. This supports the idea that kisspeptin-10 acts directly on the ovary, not just through the brain.

The three new studies look at different time points and different outcomes, so a table helps separate them.

The pregnancy study looks at a later outcome (pregnancy loss), the infertility study looks at a current condition, and the mouse study looks at early ovarian changes after treatment.

In the short term, human studies show that giving kisspeptin-10 raises luteinizing hormone and follicle-stimulating hormone within hours. For example, in healthy men, an 8-hour infusion raised these hormones in a dose-dependent way ⁴. In women with amenorrhea from a prolactin-secreting tumor, kisspeptin-10 infusions restored LH pulses and raised estradiol ⁵. The new mouse study fits this short-term pattern but adds that ovarian effects are direct ³.

In the mid term, the new infertility study shows that women with PCOS have higher kisspeptin-10, which may reflect their body's attempt to compensate for irregular ovulation, but this is not proven ². In the long term, the pregnancy study links low kisspeptin-10 in early pregnancy to a higher chance of loss, though the number of losses was small ¹. Earlier work in placental cells found kisspeptin-10 limits how deeply the placenta invades the uterine wall, so low levels may matter for early pregnancy ⁶.

The pregnancy study measured kisspeptin-10 once, early in pregnancy. It is not clear whether a single measurement can reliably predict loss in a larger group, because the study had only 30 losses and the estimate is not precise. The infertility study was cross-sectional, so it cannot show whether high kisspeptin-10 causes infertility or is a result of it. The mouse study used direct peptide administration, so its effects may not translate to human blood levels. More work is needed to see whether kisspeptin-10 can be used as a routine fertility test or whether changing kisspeptin-10 levels affects pregnancy outcomes.