Morinda citrifolia shows no reduction in menstrual pain or bleeding in women with primary dysmenorrhoea: Study

Primary dysmenorrhoea occurs without identifiable pelvic pathology, while secondary dysmenorrhoea is associated with pelvic conditions such as endometriosis, adenomyosis, uterine leiomyomata, or chronic pelvic inflammatory disease.

Morinda citrifolia, commonly known as Noni, is a tree from the coffee family, Rubiaceae. It is native to Southeast Asia and Australasia and has been used in Polynesian folk medicine for more than 2,000 years. Previous reports have described potential therapeutic effects, including anti-inflammatory, immunomodulatory, gastrointestinal, analgesic, and other health-related benefits.

Noni is commonly used in Jamaica, particularly in rural communities. The fruit is prepared in several forms, and Noni juice and capsules are commercially available in many pharmacies. Its reported analgesic effect has been linked to cyclooxygenase inhibition, and it has also been described as having tranquilizing properties. Some reports have suggested that it is nonaddictive and free from side effects.

The researchers conducted a randomized, double-blind, placebo-controlled study to evaluate whether 400 mg of Noni taken twice daily could reduce menstrual pain and menstrual blood loss in women with primary dysmenorrhoea. Each participant was followed for three months, including one month for baseline cycle assessment.

The study was designed as a superiority trial to test whether Noni was more effective than placebo. Pain was measured using visual analog pain scores, while menstrual bleeding was measured using pictorial charts. These were treated as the primary endpoints. Secondary endpoints included haemoglobin, packed cell volume or hematocrit, and erythrocyte sedimentation rate.

The trial used a repeated-measures design, with one baseline measurement and two post-treatment measurements. A sample size of 40 participants in each group was calculated to detect a 0.5 standard deviation difference in pain scores between the Noni and placebo groups, assuming 90% power and an alpha of 0.05.

The prospective trial involved university students aged 18 years and older over three menstrual cycles. Participants were invited to take part and were randomly assigned to receive either 400 mg Noni capsules or placebo. Baseline demographic variables, including age, parity, and body mass index, were recorded. Participants were also assessed before and after treatment for pain, menstrual blood loss, erythrocyte sedimentation rate, haemoglobin, and packed cell volume.

Of the 1,027 women screened, 100 eligible women were randomized. Among those who completed the study, 42 were assigned to the Noni group and 38 to the placebo group. There were no significant differences between the groups in demographic variables, bleeding scores, or pain scores at randomization.

Both bleeding and pain scores gradually improved in the Noni and placebo groups over the three menstrual cycles. However, the improvement in the Noni group was not significantly different from that observed in the control group.

The researchers noted that the dose used in the study was 400 mg twice daily for five days, selected for ease of administration. Other preparations and doses, including 500 mg extracts and Noni juice, have been used in different settings. Toxicity studies in mice reportedly showed no adverse effects, suggesting that a higher dose may be required before a significant therapeutic effect can be observed.

Only 80 of the 100 randomized participants were included in the final analysis, with 38 in the placebo group and 42 in the Noni group. Based on this relatively small sample size, the observed decrease in pain appeared to be consistent with a placebo effect. The researchers concluded that further studies using higher doses of Noni and larger sample sizes are needed.

Source: Hindawi Publishing Corporation, Obstetrics and Gynecology International, Volume 2013, Article ID 195454, 6 pages.