Reproductive sciences (Thousand Oaks, Calif.)Aug 5, 2015

Different Strengths of Labor-Preventing Drugs and Progesterone on Uterine Muscle from Single and Twin Pregnancies

Circadian Biology Weekly Brief ↗PubMed ↗DOI ↗

Updated Apr 4, 2026

Abstract

Both indomethacin and progesterone require greater concentrations to effectively inhibit oxytocin-induced contractions in twin pregnancies compared to singletons.

All tested agents showed a concentration-dependent relaxant effect on myometrial contractions.
No significant differences were found in relaxant effects between singleton and twin pregnancies for progesterone or indomethacin on spontaneous contractions.
Under oxytocin stimulation, indomethacin and progesterone displayed significantly shifted concentration-response curves for both amplitude and activity integral.
Twin myometrium exhibited significantly greater concentration-response curves for progesterone (P < .05) and indomethacin (P < .001) compared to singleton myometrium.
These findings suggest that the pharmacologic responses of myometrial tissue may differ between singleton and twin pregnancies.

Simplified

We compared the relaxant effect of 2 known tocolytics; indomethacin and atosiban and progesterone, on pregnant human myometrial spontaneous and oxytocin-induced contractions from singleton and twin pregnancies. All agents exerted a concentration-dependent relaxant effect on myometrial contractions. There was no significant difference in the concentration-response curves between singletons and twins for progesterone or indomethacin on spontaneous contractions or atosiban on oxytocin-induced contraction. Under oxytocin however, the concentration-response curves for indomethacin and progesterone were significantly shifted to the right for both amplitude of contraction (P < .01) and activity integral (P < .01). When compared to singleton myometrium however, the concentration-response curves were significantly shifted to the right in the twin myometrium group (P < .05 progesterone and P < .001 indomethacin). We conclude that a greater concentration of progesterone and indomethacin is required to inhibit oxytocin-induced myometrial contractions in twins compared to singletons in vitro. The differences noted in the tissue pharmacologies may have implications for the successful prevention or inhibition of preterm labor in twin pregnancy.

Full Text

Full text is available at the source.

View Full Text ↗

Different Strengths of Labor-Preventing Drugs and Progesterone on Uterine Muscle from Single and Twin Pregnancies

Abstract

Full Text

You found one interesting study. We’ll send the next 7.

what lands in your inbox each week:

Recent issues from the circadian biology brief

Abstract

Full Text

Related papers

You found one interesting study. We’ll send the next 7.

what lands in your inbox each week:

Recent issues from the circadian biology brief