After reading this article, you should be able to:
- Understand how primary and secondary dysmenorrhoea are differentiated and their underlying pathophysiology;
- Recognise the symptoms of primary and secondary dysmenorrhoea and understand how to take an appropriate patient history to aid diagnosis;
- Manage patients with dysmenorrhoea, including referral and provision of advice relating to over-the-counter analgesics.
Dysmenorrhoea, commonly referred to as ‘period pain’, is pain felt usually in the lower abdomen, which occurs shortly before and/or during menstruation.
Prevalence is difficult to determine because different definitions and diagnostic criteria for dysmenorrhea are used and it is often underestimated and undertreated. Prevalence rates vary widely in the literature, from 16–91% in women of reproductive age, with 2–29% reporting severe pain[2,4]. The wide variation in reported prevalence is probably also a result of diverse study populations and different methods of data collection. However, dysmenorrhoea is one of the most common gynaecological symptoms affecting the quality of life of menstruating women and is a substantial public health burden[2,3].
Dysmenorrhea can decrease quality of life and lead to restriction of daily activities and absence from school or work[2,4]. Around 30–50% of women affected by primary dysmenorrhoea are reported to miss work or school at least once per cycle, with 5–14% missing work or school more frequently. Women with dysmenorrhoea also have poorer mood and sleep quality during menstruation than during their pain-free phase, and greater pain sensitivity throughout their menstrual cycle that can subsequently increase susceptibility to other chronic pain conditions (e.g. fibromyalgia). Despite the impact on quality of life and general wellbeing, few women seek medical treatment and accept dysmenorrhoea as part of their normal menstrual cycle.
This article outlines the causes, pathophysiology, diagnosis and management of primary and secondary dysmenorrhoea.
Causes and pathophysiology
Dysmenorrhoea is classified as either primary or secondary; it is not always easy to distinguish between the two based on history and examination alone.
Primary dysmenorrhoea is not associated with any identifiable underlying pelvic pathology and usually occurs in young females 6–12 months after menarche (i.e. first menstruation), once cycles become regular. It is thought to be caused by the release of uterine prostaglandins during menstruation. Progesterone levels decrease before menstruation, causing endometrial cells to release prostaglandins that then stimulate uterine myometrial contractions. This results in decreased blood flow, uterine hypoxia and subsequent pain. Vomiting, nausea and diarrhoea can also result from the effects of prostaglandins on smooth muscles and are frequently experienced with primary dysmenorrhoea[2,5]. Leukotrienes and vasopressin may also play a role in the aetiology of primary dysmenorrhoea[2,5].
Secondary dysmenorrhoea is caused by an underlying pelvic pathology, such as pelvic inflammatory disease, endometrial polyps, fibroids, adenomyosis, intrauterine device insertion or endometriosis. It often occurs as a new symptom after several years of menstruation[2,6].
Risk factors for primary dysmenorrhoea include:
- Early age of menarche;
- Heavy menstrual flow;
- Nulliparity (i.e. never given birth);
- Family history of dysmenorrhoea;
There is conflicting evidence on the association between primary dysmenorrhoea and modifiable risk factors — such as cigarette smoking, diet, obesity, depression and a history of sexual abuse — and insufficient data to support an association with nutritional deficiency. However, in women with iron deficiency, iron supplements can cure or improve dysmenorrhoea.
Risk factors for secondary dysmenorrhoea are dependent on the underlying cause.
Pain associated with primary dysmenorrhoea is usually cramping in nature and felt in the lower abdomen, but can radiate to the inner thigh and back[2,8]. The pain can be sporadic and intense or constant and dull and may vary with each period. Other features and symptoms of primary dysmenorrhoea include:
- Onset of pain at 6–12 months after menarche (i.e. once cycles are regular);
- Pain commences shortly prior to menstruation and continues for up to 72 hours, improving as menses progresses;
- Non-gynaecological symptoms include nausea, vomiting, diarrhoea, fatigue, irritability, dizziness, bloating, headache, lower back pain and emotional symptoms;
- No other gynaecological symptoms;
- Normal pelvic examination.
The onset of pain in secondary dysmenorrhoea often occurs after several years of menstruation and is not consistently related to menstruation, however it may be exacerbated by and persist after menstruation, or be present throughout the menstrual cycle. Other gynaecological symptoms include dyspareunia (i.e. painful sexual intercourse), intermenstrual bleeding, vaginal discharge, menorrhagia (i.e. heavy or prolonged bleeding) and postcoital bleeding. Non-gynaecological symptoms, such as rectal pain and bleeding, may also be present.
Secondary dysmenorrhea must be excluded prior to a primary dysmenorrhoea diagnosis. To exclude secondary dysmenorrhoea, a thorough history should be taken and should include:
- When symptoms started in relation to menarche;
- A description of the pain including timing and duration, type and severity, and any factors that alleviate or exacerbate the pain;
- Associated gynaecological and non-gynaecological symptoms;
- Length, regularity and duration of menstrual cycle;
- Volume of menstrual flow;
- Presence of risk factors for primary dysmenorrhoea
- Medical history to identify possible conditions with similar symptoms to dysmenorrhoea (e.g. irritable bowel syndrome and lactose intolerance);
- Obstetric history, including plans for pregnancy;
- Medication history, including effectiveness of any previous treatments.
A physical examination should include a physical abdominal examination to assess for large fibroids and other masses. A pelvic examination (including a speculum examination of the cervix), except in young women who are not sexually active, should be performed to check for sexually transmitted diseases. Further investigations may also include an ultrasound scan (to assess whether there are fibroids, adnexal pathology or endometriosis), high vaginal and endocervical swabs (to exclude sexually transmitted diseases), and a pregnancy test to exclude ectopic pregnancy.
Conditions that are likely to cause secondary dysmenorrhoea and their symptoms are listed in Table 1[2,3,7].
Treatment and management
Before advising on treatment, secondary causes of dysmenorrhoea must be excluded by taking a history and checking for symptoms (see Table 1)[2,3,7]. Pharmacists should ask about the history and nature of symptoms and be sure they fit the symptoms of primary dysmenorrhoea, as outlined under ‘Diagnosis‘.
Once primary dysmenorrhoea has been confirmed, pharmacists can offer advice on self-management, including the supply of over-the-counter (OTC) medicines for pain. When supplying OTC medication, pharmacists should ask about contraindications and medication history, and consider potential drug interactions. Advice should be offered on how and when the medicine should be taken (see Table 2).
Primary dysmenorrhoea can be treated with simple OTC analgesics. A nonsteroidal anti-inflammatory drug (NSAID), either ibuprofen or naproxen, can be offered over the counter unless contraindicated (see Table 2). Other NSAIDs, including mefenamic acid, flurbiprofen and tiaprofenic acid, can be offered on prescription[10–14]. There is little evidence to suggest variation in efficacy between NSAIDs but there are concerns that mefenamic acid is more likely to cause seizures in overdose than other NSAIDs.
NSAIDS are more effective at treating pain from dysmenorrhoea than paracetamol. Paracetamol should be offered if NSAIDs are contraindicated or not tolerated, and can be taken in addition to an NSAID if the pain is not treated with an NSAID alone.
If the woman does not wish to conceive, referral to her GP for a 3–6 month trial of a hormonal contraceptive could be considered as an alternative treatment.
In addition to pharmacological measures, use of a hot water bottle, heat patch or transcutaneous electrical nerve stimulation set at a high frequency can be suggested for further pain relief.
Although the evidence for an association between modifiable risk factors and primary dysmenorrhoea is inconsistent, encouraging smoking cessation, weight management, general fitness, a healthy diet and good mental health practices may be beneficial to general health and wellbeing for women experiencing primary dysmenorrhoea.
When to refer
Women should be referred to their GP if symptoms of secondary dysmenorrhoea are reported, or her signs and symptoms do not suggest primary dysmenorrhoea.
A woman aged 45 years presents at her local pharmacy and asks to speak to the pharmacist. She is concerned about her 13-year-old daughter who has recently started complaining of period pain and not wanting to eat during her periods.
It is important to assess if the patient could have an underlying pathology indicative of secondary dysmenorrhoea or a non-gynaecological condition before making a diagnosis of primary dysmenorrhea. The discussion should include the following questions:
- How long ago did menstruation begin and is the cycle regular?
- When did menstruation become painful?
- What is the cause of not wanting to eat?
- Are there any other symptoms?
- Do the symptoms occur only during menstruation or also at other times of the cycle?
After the consultation, the pharmacist learns that the woman’s daughter started menstruating nine months ago and her cycle is now regular. Apart from dull muscle cramps she also feels nauseous during menstruation, and this is the cause of her loss of appetite. The symptoms usually begin just before menstruation and subside a couple of days later. She does not have any other symptoms.
As there are no signs of underlying disease or secondary dysmenorrhea, the pharmacist is reassured the patient is experiencing pain and nausea as common symptoms of primary dysmenorrhea.
Treatment and advice
After checking for other medical conditions and allergies, the pharmacist advises using a hot water bottle applied to the lower abdomen and ibuprofen 300–400mg up to three times a day, at least four hours apart and for no more than three days. The pharmacist advises that ibuprofen is usually well tolerated but should be taken with or just after food.
When to refer
If the patient experiences any side effects or if the ibuprofen is ineffective, the patient should be advised to come back to the pharmacy to be reassessed and possibly referred to her GP.
A 30-year-old woman comes into the pharmacy to purchase naproxen for her period pain. She tells the pharmacist that the pain is quite low down in her abdomen just above her legs and below her belly button. The duration of pain is not restricted to her periods and she has noticed some vaginal discharge that’s often tainted with blood. As she has no other symptoms, she is confident it is period pain.
The pharmacist asks the patient about the onset and nature of her symptoms, including any non-gynaecological symptoms, comorbidities and allergies. It is important to determine whether there is something more serious as the patient’s symptoms and their onset are consistent with secondary dysmenorrhoea. The pharmacist explains the concern and advises her to see her GP. The patient would still like to purchase naproxen to help control the pain in the meantime. The patient explains that she had a stomach bleed about three months ago and had to take some tablets for a week. She is not currently taking any other medication, has no allergies and no other significant past medical history.
Treatment and advice
The pharmacist advises the patient that naproxen is not appropriate because of her recent stomach bleed and recommends 500mg paracetamol and some heat patches to apply to her pelvic area. She is advised to take two tablets every four to six hours as required, ensuring that she doesn’t take more than eight tablets per day, including any other preparations that contain paracetamol. The pharmacist explains that paracetamol is usually well tolerated and recommends that she see her GP as soon as possible.
A 40-year-old woman presents to the pharmacy and explains that she has previously been diagnosed with endometriosis and has been taking a combined oral contraceptive (COC). Her symptoms have recently gotten worse and she would like advice on what she can take or do to help relieve the symptoms.
It is important to establish whether referral is required. The pharmacist asks the patient about the onset and nature of her symptoms and whether improvement was achieved by the COC; as well as enquiring about any concurrent symptoms, comorbidities and allergies.
The patient explains that her symptoms (i.e. cyclical pelvic pain with associated rectal pain and heavy menstrual flow) improved when she started the COC. Apart from the worsening of symptoms, the patient does not have any other symptoms, comorbidities or allergies.
Treatment and advice
The pharmacist suggests that she try heat packs and warm baths and offers her 300–400mg ibuprofen up to three times a day, at least four hours apart, and reassures her that side effects are uncommon. The patient should be reminded to see her GP if symptoms are not relieved and/or persist; and informed that her endometriosis may require further investigation and medical intervention, including referral to a specialist.
* All cases are fictional
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