Symptoms of painful menstrual periods are alleviated by taking the combined oral contraceptive pill, according to compelling evidence from a Scandinavian 30-year study which was reported in the journal Human Reproduction this week. Although previous studies pointed towards some kind of link between oral contraception and period pain relief, a 2009 Cochrane Collaboration review concluded that most of them had inconclusive or anecdotal evidence.
In this new study, Dr Ingela Lindh and team, from the Institute of Clinical Sciences, Sahlgrenska Academy at Gothenburg University, Sweden, showed that females who take the combined oral contraceptive pill experience less severe pain and discomfort compared to other women of the same age.
The authors explained that younger females tend to have more severe dysmenorrhea (menstrual pains) than older ones. They added that symptoms do tend to improve as sufferers get older. However, they stressed that the effects of the combined oral contraceptive pill were independent of age – and that the effects of the pill are far greater than age.
The investigators gathered data on three groups of between 400 to 520 adult females who reached 19 years of age in 1981, 1991, and 2001. They had information on the participants’ weight, height, pattern of menstruation, menstrual pain, and reproductive history. All the women were followed up when they were 24 years old.
Because each woman was assessed twice (at 19 and 24 years), they were able to use each one as her own control. This allowed the researchers to determine what impact age and COC (combined oral contraceptive) had.
Dr Lindh said:
“By comparing women at different ages, it was possible to demonstrate the influence of COCs on the occurrence and severity of dysmenorrhea, at the same time taking into account possible changes due to increasing age. We found there was a significant difference in the severity of dysmenorrhea depending on whether or not the women used combined oral contraceptives.”
The authors used two ways of measuring the severity of symptoms: 1. Verbal multidimensional scoring system (VMS), where the woman grades her pain as none, mild, moderate and severe. VMS also includes what effect period pains might have on the woman’s daily activities and whether she needed any painkillers. 2. Visual analogue scale (VAS), where the pain is scaled on a 10 cm line, starting at “no pain at all” and ending at “unbearable pain”.
Dr Lindh said:
“We found that combined oral contraceptive use reduced dysmenorrhea by 0.3 units, which means that every third woman went one step down on the VMS scale, for instance from severe pain to moderate pain, and which meant that they suffered less pain, improved their working ability and there was a decrease in the need for analgesics. On the VAS scale there was a reduction in pain of nine millimetres.”
Age reduced dysmenorrhea symptoms by 0.1 units on the VMS scale and 5 mm on the VAS scale. They also found that childbirth improved subsequent symptoms – however, the authors stress that there were not enough women giving birth to make any reliable conclusions. Asked why younger women tended to have worse symptoms, Dr. Lindh said:
“We are unsure why this is. It may be due to changes in the type of oral contraceptive used, for example, differences in oestrogen content and progestogen type, or a different appreciation of pain in the women born in later years, in that they may be more pain sensitive or are more prepared to complain about pain than women of the same age but born earlier.”
US health authorities believe that dysmenorrhea accounts for 600 million lost hours of work, costing the country’s economy over $2 billion annually.
Dr Lindh said:
“Painful periods occurs frequently, particularly in young women where as many as 50-75% suffer from dysmenorrhea. It can have a detrimental effect on these women’s lives, causing regular absenteeism from school and work, and interfering with their daily activities for several days each month. Therefore effective management of dysmenorrhea is beneficial for both the women affected and society.
Information about the effects of COC use on painful periods should be included in contraceptive counseling, as it has been shown that women who experience a beneficial effect of COCs other than contraception, such as a reduction in dysmenorrhea, are more likely to continue with the pill.”
To include dysmenorrhea treatment as another indication for COC, US and European regulatory authorities would require a randomized controlled human study. On both sides of the Atlantic, thousands of doctors already prescribe COC “off-label” for menstrual pains.
Dr Lindh said:
“We are aware that drug companies have discussed with the authorities the possible design of a randomized controlled trial for the evaluation of COCs in the treatment of dysmenorrhea, but this has not yet been finalized or performed. However, our study has clearly indicated a beneficial influence of COCs on the prevalence and severity of dysmenorrhea and the absence of a randomized controlled trial confirming this in no way reduces the value of this information.”
Written by Christian Nordqvist