Adding L-carnitine to clomiphene resistant PCOS women improves the quality of ovulation and the pregnancy rate. A randomized clinical trial

Eur J Obstet Gynecol Reprod Biol. 2014 Sep:180:148-52. doi: 10.1016/j.ejogrb.2014.06.008. Epub 2014 Jun 23.


Objective: To evaluate the effectiveness of L-carnitine on improving the ovulation and pregnancy rates as well as adverse metabolic indices in clomiphene-resistant PCOS.

Design: Single center, double blinded, superiority, randomized controlled clinical trial.

Setting: Women's Health Hospital, Assiut University.

Methods: One hundred and seventy women diagnosed with PCOS were found to be clomiphene resistant. The women were randomly allocated into two groups: Group A (n=85), where patients received 250 mg clomiphene citrate from day three until day seven of the cycle plus L-carnitine (LC) 3g daily; and Group B (n=85) received 250 mg clomiphene citrate with placebo.

Outcome: Primary outcome is cumulative clinical pregnancy rate. Secondary outcomes are changes in serum glucose level and lipid profile.

Results: The combination of L-carnitine and CC significantly improve both the ovulation and the cumulative pregnancy rates in clomiphene resistant PCOS (55 (64.4%) vs. 15 (17.4%) and 44 (51.5) % vs. 5 (5.8) %). The number of stimulated follicles reaching ≥17 mm diameter was significantly more in Group A to Group B (2.2 ± 0.77 vs. 0.16 ± 0.79; p<0.0001). Group A needed significantly fewer days for adequate follicular maturation, had a thicker endometrium and higher oestradiol concentration at the time of human chorionic gonadotrophin injection (10.1 ± 0.1mm vs. 6.8 ± 0.4mm; p<0.0001). The same group had a higher mean luteal-phase serum progesterone compared with the control group (13.55 ± 0.99 vs. 10.6 ± 0.98 ng; p<0.0001). A significant difference was found regarding the clinical pregnancy rates (42 (49.4%) vs. (1) 1.1% respectively p value <0.0001).

Conclusion: Adding L-carnitine when treating clomiphene-resistant PCOS patients not only improved the quality of ovulation and the pregnancy rate with an acceptable patient tolerability, but also enhanced the patient lipid profile and body mass index.

Keywords: Induction of ovulation; Oxidative stress; PCOS; l-carnitine.

Publication types

  • Randomized Controlled Trial
  • Retracted Publication

MeSH terms

  • Adult
  • Carnitine / therapeutic use*
  • Clomiphene / therapeutic use*
  • Double-Blind Method
  • Drug Resistance
  • Drug Synergism
  • Drug Therapy, Combination
  • Female
  • Fertility Agents, Female / therapeutic use*
  • Follicle Stimulating Hormone / blood
  • Humans
  • Infertility, Female / drug therapy*
  • Infertility, Female / etiology
  • Luteinizing Hormone / blood
  • Ovulation
  • Ovulation Induction / methods
  • Polycystic Ovary Syndrome / complications
  • Polycystic Ovary Syndrome / drug therapy*
  • Pregnancy
  • Pregnancy Rate*
  • Treatment Outcome
  • Vitamin B Complex / therapeutic use*
  • Young Adult


  • Fertility Agents, Female
  • Vitamin B Complex
  • Clomiphene
  • Luteinizing Hormone
  • Follicle Stimulating Hormone
  • Carnitine