Evening primrose oil: an economical alternative for cervical ripening for labor induction

Grace Lynn Estanislao, MD-MBA, DPOGS

Maria Rosario Castillo-Cheng, MD, FPOGS, FPSMFM

Objective: To evaluate the effectiveness of oral and intravaginal evening primrose oil  for labor induction in  term singleton pregnancies  by systematic collection and analysis of published studies on its use for cervical ripening

Primary outcome measure: Improvement in Bishop score

Evening primrose oil Labor induction Cervical ripening

Systematic review and meta-analysis

Inclusion criteria

The two Filipino studies (Ty-Torredes et al and Pineda) showed a statistically significant increase in Bishop score in the EPO group compared to placebo, with a mean of 5.5 for the intravaginal EPO, and 6.31 for the oral EPO. The use of intravaginal EPO showed a greater increase in Bishop score (5.5 vs 3.48), compared to the use of oral EPO (6.31 vs 4.72). The Iranian study (Kalati et al), which also used oral EPO, showed a larger mean change in Bishop Score in the placebo group compared to the EPO group (4.35 vs 3.60).

The use of oral and intravaginal evening primrose oil capsules leads to a significant increase in Bishop Score compared to placebo in term singleton pregnancies with a Bishop Score of 4 or below. 

The evidence presented in this review suggests that evening primrose oil is an effective, viable, alternative agent for the use of cervical ripening in labor induction.