DOI: 10.4103/pjog.pjog_15_25 ISSN: 2772-9567

Effect of evening primrose oil on cervical ripening among term pregnant women as measured by cervical elastography: A randomized controlled trial study

Kriska Noelle Valencia Raymundo, Leah Socorro N. Rivera
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OBJECTIVE:

The objective of this study was to evaluate the effectiveness of evening primrose oil (EPO) for cervical ripening in term pregnant women using cervical elastography.

METHODOLOGY:

A single-blind, randomized controlled trial was conducted with 62 term pregnant women at the University of Santo Tomas Hospital from July to November 2024. Participants were randomized into treatment ( n = 32) and control ( n = 30) groups. The treatment group received 1000 mg intravaginal EPO capsules twice daily for 7 days starting at 37 weeks’ gestation. Cervical elastography parameters, including elasticity index, hardness ratio, internal os strain (IOS), external os strain (EOS), and cervical length, were measured at baseline and after 1 week. Clinical outcomes, including Bishop score, labor duration, and delivery outcomes, were also assessed.

RESULTS:

The treatment group showed significantly lower mean hardness ratio (43.4% vs. 53.7%, P = 0.0075) and shorter cervical length (2.7 cm vs. 3.3 cm, P = 0.0085) compared to controls at 38 weeks. The EPO group demonstrated significant improvements from baseline in elasticity index, IOS, EOS, hardness ratio, and cervical length (all P < 0.00001), whereas the control group showed minimal changes. The treatment group had higher median Bishop scores (4 vs. 3, P = 0.0067) and shorter median labor duration (6.5 vs. 9.5 h, P = 0.0303). No significant differences were observed in cesarean section rates, APGAR scores, or neonatal complications between groups.

CONCLUSION:

EPO demonstrates effectiveness as a cervical ripening agent among term pregnant women, as evidenced by significant improvements in cervical elastography parameters and clinical outcomes, without increasing adverse events. Cervical elastography provides objective quantification of these effects, supporting its utility in assessing cervical changes during the ripening process.

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