Women

Menstrual cycle

The normal cycle lasts from 21-36 days. The first day of menstruation is day 1 of the cycle.
The cycle usually consists of 3-5 days of menstruation. Follicular phase is from last day of menstruation to ovulation which occurs at approximately 14 days, and the luteal phase lasts from ovulation to menstruation, which is approximately 15-28 days.
A cycle lasting fewer than 21 days is polymenorrhoea and longer than 36 days is oligomenorrhoea. Secondary amenorrhoea is defined as having had no periods for 3-6 months.

Hormonal changes that occur during the menstrual cycle

Gonadotrophin-releasing hormone (GnRH) causes the synthesis, storage, and the activation release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH).

During the follicular phase, levels of oestrogen increase so that both LH and oestrogen peak just before ovulation. Oestrogen then falls and rises again during the luteal phase. Progesterone is secreted by the corpus luteum during the luteal phase, and both oestrogen and progesterone levels fall if fertilization does not take place. Hormone levels should normally be tested after the 21st day of the cycle, during the luteal phase.

Physical exercise produces marked changes in the post-exercise pulsatile, secretion of LH, FSH, oestrogen, and progesterone, and cortisol. The more intense and longer the duration of exercise the greater the effect, resulting in marked changes in the menstrual cycle. Factors associated with changes to the normal menstrual cycle include:

Psychological stress.
Physical exercise.
Seasonal rhythms.
Circadian rhythms.
Strenuous exercise causes an increase in dopamine, which inhibits GnRH, beta endorphins, catecholamines, oestrogens.
Beta endorphins stimulate dopamine and combine with noradrenaline receptors in the hypothalamus, which inhibit stimulation of GnRH.

Menarche

The average age for menarche in Europe is 12-13.4yrs and in the USA, for Caucasians, it is 12.8yrs. Failure to menstruate after 16yrs of age is considered to be late menarche and the cause should be investigated. Tall thin girls tend to have a later menarche than small larger girls. In some cases, bone age may be below the chronological age due to illness or inadequate nutrition. To determine this, X-ray the carpal bones of the left hand. These can be compared with standards established by Greulich and Pyle, Tanner and Fels. To overcome X-ray exposure, there have been more recent efforts to standardize using MRI.

Later menarche tends to occur in gymnasts, ballet dancers, and athletes who start high intensity training early. Other factors which may delay menarche include low caloric intake, low body fat and high emotional stress.

Primary amenorrhoea

Any girl, who by the age of 13, has not developed any secondary sexual characteristics, or who has not menstruated by the age of 16 should be evaluated and examined. This should include a detailed medical, family, and nutritional history and, in an athlete, a record of her training and competition. Physical findings will direct the appropriate investigations and may indicate referral to a gynaecologist. The preliminary tests should include hormone levels (FSH, LH, oestrogen, progesterone, testosterone, prolactin, and thyroid function tests), US of the pelvis, and investigation for chromosomal abnormalities. Treatment for delay of menarche is advised at 18yrs because of the risk of osteopenia.

Menstrual irregularities

Menstrual irregularities tend to occur in the athletes with the most intense training schedules or in those who have participated or competed for the longest period of time.

Polycystic ovary syndrome (PCOS) is a common and congenital cause of menstrual disorders, and can lead to a slight increase in testosterone production. Polycystic ovaries—part of PCOS, were more common amongst elite Olympic athletes (37%), than amongst women on average (20%).
Vegetarians and people with a low caloric intake have the highest incidence of oligomenorrhoea and amenorrhoea.
Menstrual irregularities are reported in 7% of recreational runners, 12% of swimmers, and 25% of distance runners.
The incidence depends on how the menstrual irregularities are assessed and vary in studies by questionnaire or measured hormone levels.

About one-third of athletes believe that menstruation affects performance, but medals have been won during all phases of the menstrual cycle. There are no medical contraindications to exercise while menstruating. The effects of menstruation on performance appear to be sports related.

Athletes with menstrual problems often had them prior to training. Many ‘normal’ cycles show abnormal serum hormone levels after 21st day of cycle. Non-athletes also have problems. A mother’s attitude to menstruation is often reflected in the daughter.

Multifactoral causes of all menstrual irregularities

Stress, both psychological and physical. Severe emotional stress acts above hypothalamic-pituitary axis.
Sudden increases in the quantity and intensity of training or increase in the number of competitions.
Late menarche, irregular cycle prior to sports participation, intense training prior to menarche, and an immature pituitary axis.
Inadequate nutrition, weight loss. Decreased caloric intake, and a low protein, high fibre diet results in a high serum sex hormone-binding globulin and low oestrogen, which predispose to amenorrhoea.

Amenorrhoea

Higher incidence of musculoskeletal problems and stress fractures in amenorrhoeic athletes, particularly those with irregular menstrual cycles. Amenorrhoeic athletes with hyperprolactinaemia have an associated low bone mineral density.
Cannot assume an amenorrhoeic athlete is infertile.
Must rule out pregnancy and other causes of amenorrhoea.

Progression of menstrual changes due to strenuous exercise

Stage 1: normal follicular, normal luteal phase.
Stage 2: prolonged follicular and a shortened luteal phase results in luteal phase defects, which is associated with infertility and premenstrual tension.
Stage 3: euoestrogenic anovulatory oligomenorrhoea, possibility of endometrial hyperplasia adenocarcinoma if this phase persists
Stage 4: hypo-oestrogenic—amenorrhoea leads to osteoporosis and genital atrophy.

Dysmenorrhoea

Dysmenorrhoea is due to the release of prostaglandins and is limited to an ovulatory cycle.
Exercise has a beneficial effect and dysmenorrhoea is rare in an athlete.
If dysmenorrhoea is present, look for pathology, e.g. fibroid or ovarian cysts, polycystic ovarian syndrome, or endometriosis.

Premenstrual syndrome

Premenstrual syndrome (PMS) in athletes may cause problems in sports that require fine judgement; women are more accident prone, and more intolerant to alcohol. It results in irritability, mood swings, and fluid retention.
Patients with premenstrual tension should not scuba dive. Judgement is poor and they are more accident prone.
Diuretics should not be prescribed in athletes. Reduce training. (It is better to reduce training intensity than to over-medicate in a case of PMS, but there may be situations where mild diuretics are indicated and, as long as hydration is adequate for performance, they can be used safely and effectively. Remember the rules on doping, where appropriate)

Contraception

Barrier methods include condoms, either on their own or in conjunction with barrier creams, i.e. spermicidal cream or gel. Diaphragm, if correctly fitted, can be worn during exercise with hardly any side effects. Intra-uterine devices may cause increased pain and bleeding. Barrier methods are not as reliable as the pill, but have fewer side effects.

It is important to start treatment with the pill, combined or progesterone only, well in advance of any competition due to individual variations in reactions to the pill. Depot- Provera should not be given to young athletes between 16-20 years, when 60% of their bone will be laid down. Depot-Provera affects bone accrual, particularly if there are other risk factors. DXA should be performed before each injection, if there is no alternative. Bone mineral density should be monitored by DEXA to study the effect on bone growth. Particularly common in the teens and early twenties.

The oral contraceptive pill can be prescribed safely from 16yrs or 3yrs post-menarche.
Low dose oral contraceptive pill, which consists of a combination of oestrogen and progestogens, can regulate the cycle, control the pain of dysmenorrhoea, and prevent early osteoporosis.
Progesterone only oral contraceptive pill inhibits ovulation, but it is not as effective at reducing pain.

Treatment of menstrual irregularities

The team approach should include the athlete, physician, physiotherapist, nutritionist, physiologist, and psychologist.