The transport of early embryos through the fallopian tubes and into the uterus is regulated by hydrogen sulphide signalling, according to a study published this week in Nature Communications. The study enhances our understanding of the mechanisms underlying impaired tubal transport, which has been associated with ectopic pregnancy.

Hydrogen sulphide is produced from the amino acid L-cysteine by three enzymes, two of which are present in male and female reproductive systems.

Jingxin Li and colleagues show that pharmacological or genetic disruption of hydrogen sulphide signalling in pregnant mice resulted in aberrant pregnancies. The authors then prevented this by administering a drug that releases hydrogen sulphide.

In addition, the authors suppressed fallopian tube motility in excised human fallopian tube samples by inhibiting the production of hydrogen sulphide. They also observe that hydrogen sulphide signalling is upregulated in the fallopian tube epithelium of women with ectopic pregnancies, suggesting that dysregulation of hydrogen sulphide metabolism might be involved.