Menstruation and Pregnancy

Menstruation and Pregnancy

The large number of descriptive terms that are used to describe menstruation, such as ‘having a period’, ‘the curse’, and so on, are more than equalled in number by the greatly varying views that women express on the subject. These differing views can be clearly recognized when a woman reaches the menopause and menstruation ceases. Some see this as a release from a lifetime of menstrual problems and inconvenience; others are saddened at the loss of their fertility and may feel a sense of ‘bereavement. Others will experience a mixture of both feelings.

Menstruation is the normal monthly discharge of blood from the uterus by way of the vagina. This process occurs because a woman’s uterus prepares itself to accept a fertilized egg, and when pregnancy does not occur, this specially prepared uterine lining is shed in the form of blood and cellular debris. Menstruation usually starts between the ages of 11 and 14 years. The first period is called the menarche. Periods may be irregular for the first year or so, and also after the age of 45 years when a women’s fertility begins to reduce. The last period occurs around the age of 50 and is known as the menopause. Menstruation, which is only a part of the menstrual cycle, lasts two to seven days (four days on the average). The cycle occurs over a time span of about 28 days throughout a woman’s childbearing period, usually some 35 years. The first day of menstruation is usually regarded as the first day of the menstrual cycle; but it has to be kept in mind that, because it is a cycle, there is not an absolute point of beginning. In fact, menstruation is the resulting phase of the changes occurring in the phase before.

Stages of the menstrual cycle

The menstrual cycle can be thought of in three phases, related to the state of the uterine wall. For each stage there is a complex interaction of four main hormones: follicle-stimulating hormone (FSH), oestrogen, luteinizing hormone (LH) and progestrone.

The proliferative phase

During menstruation the hypothalamus, which is located in the base of the brain, secretes quantities of follicle-stimulating hormone releasing factor (FSHRF) to stimulate the cells in the pituitary gland, just below the brain, to produce FSH. The FSH level in the blood rises and stimulates cells in the ovary known as ovarian follicles which ultimately form an egg (ovum). As these follicles grow they release oestrogen into the blood which helps to stimulate the rebuilding of the uterine wall. Oestrogen stimulates the growth of endometrial glands embedded in the lining and causes the surrounding cells to proliferate, hence the first two weeks of the menstrual cycle are called the proliferative phase.

By about the fourteenth day after the onset of menstruation, the level of oestrogen in the blood has risen six-fold and has a feedback effect on the hypothalamus and on the pituitary gland, causing a reduction in FSH production and an increase in luteinizing-hormone production. LH reaches, by way of the blood, the ovary and causes the ripe egg follicle to burst. The egg is pushed out, along with its suspending fluid. The release of the egg is known as ovulation. The egg is then transported into the Fallopian tube, where fertilization may occur.

The remaining empty follicle which previously contained the egg is turned yellow by the effect of the luteinizing hormone and is known as the ‘yellow body’ or more commonly by its Latin name, the corpus luteum.

Ovulation signifies the end of the proliferative phase of the menstrual cycle and the start of the secretory phase, which lasts for around ten days.

The corpus luteum produces progesterone, and prepares the uterus for pregnancy. Progesterone has several effects: it relaxes involuntary muscles, increases production of waxy skin secretions, and raises body temperature up to around 37.2°C from the normal range of around 36.7°C. However, the most important effect of progesterone is to thicken the lining of the uterus and stimulate the endometrial glands to secrete a watery mucus which nourishes a fertilized egg during its implantation in the uterus. It also assists the passage of sperm through the uterus to the Fallopian tubes where the ovum is usually fertilized.

If a fertilized egg has not embedded itself in the uterus within one week, the corpus luteum regresses with the other stimulated follicles – causing the levels of oestrogen and progesterone to fall. The reduction in the level of these hormones, causes the coiled arteries in the uterine wall to constrict and the thick, juicy lining of the uterus to shrink and break down. This signifies the start of the menstrual phase.

The menstrual phase

During the menstrual phase secretions, cells and blood from broken-down uterine capillaries, plus the unfertilized egg, exit from the uterus in the form of the menstrual flow. The amount of blood builds up in the uterine cavity, causing it to contract and expel the blood through the cervix into the vagina. After a few days the proliferative phase begins and the whole cycle occurs again.

The onset of menstruation

Women undergo hundreds of menstrual cycles during their fertile years, and the first menstruation (the menarche) is an important milestone in a girl’s life and signifies that a normal hormonal pathway exists between the hypothalamus, the pituitary, the ovaries and the uterus.

In countries such as India and Sri Lanka, the menarche is a cause for celebration because it represents the girl’s attainment of maturity and the start of her sexual and reproductive life. In other countries, including some Western nations, this event is largely ignored and is almost regarded as ‘unnatural’ – as opposed to representing the blossoming of a woman’s fertility.

The timing of the menarche is influenced by genetic, dietry, climatic and social factors. In most countries with temperate climates the average age of a girl at the menarche is about 12 to 13 years and has fallen steadily through the twentieth century, probably because of improved nutrition. However, the variation in onset is so great that it is not considered abnormal if a girl has the menarche at 17.

The amount of oestrogen produced by the ovaries gradually increases between the ages of eight and 11 and becomes cyclical about a year before the menarche. Other secondary sexual characteristics such as breast and pubic hair development often precede the menarche. Initially, menstrual periods are irregular and painless because ovulation does not occur. However, unless a girl is mentally prepared for her menarche, it may be a frightening experience.

Premenstrual syndrome

Many women suffer from the premenstrual syndrome which includes a host of complaints experienced by women in the few days preceding menstruation. It is thought that the hormonal and chemical changes that occur in a woman’s body around the time of menstruation can produce the symptoms of the syndrome. These include tension, depression, tiredness, irritability, asthma, sinusitis, backache, migraine and rapid changes in mood, although fortunately not all at the same time.

Premenstrual tension, or PMT, one form of the syndrome, encompasses depression, tiredness and irritability. These three always seem to be present together in various degrees of severity. PMT is worse under stressful situations.

PMT can lead to such irritability and confusion that it has been associated with temporary loss of judgment and the subsequent occurrence of accidents at work or in the car. Extreme claims have been made implying that PMT can initiate homicidal behaviour, but these are grossly exaggerated.

The best way to handle PMT is to try and avoid situations in which there is likely to be stress or irritation during affected days. Keeping your weight down can help discourage fluid retention and the subsequent oedema and feeling of bloatedness. For some women with very severe PMT relief can be provided by treatment with synthetic derivatives of progesterone. Doctors may prescribe diuretics if fluid retention is a particular problem. Painkillers or tranquillizers may also help alleviate symptoms and recently it has been discovered that vitamin 13,, can sometimes also be helpful.

Pelvic congestion is another version of the premenstrual syndrome. Symptoms similar to PMT occur throughout the menstrual cycle but are particularly severe in the days immediately preceding menstruation. Women feel pressure in the pelvis, suffer from backache and are generally unwell. These women

often suffer heavier periods. It is thought that emotional stress results in congestion of blood in the pelvic organs, and sufferers are advised to try and resolve emotional problems, which will consequently reduce pelvic congestion.

Painful periods

Many women suffer from dysmenorrhoea, commonly called period pains, which usually do not start until two or three years after the menarche. The pain is cramp-like around the lower abdomen, and starts in the 24 hours before menstruation and lasts for up to 24 hours during bleeding. Prostaglandins* have been found to be present in high levels in women suffering from dysmenorrhoea and drugs which inhibit the level of this chemical, aspirin for example, can help alleviate the pain. Some women find that the breathing and relaxation techniques used for natural childbirth, or the pursuit of vigorous exercise, can help them cope with the discomfort.

Another painful experience during the menstrual cycle is known as the Mittelschmerz, or middle pain, which can occur at the time of ovulation. It manifests itself as mild cramping pain in the lower abdomen on one side, and the next month usually occurs on the other side. It is thought to be caused by contractions of the Fallopian tubes as the egg makes its way down to the womb after ovulation. The pain lasts for a few hours and it may closely resemble the symptoms of an appendicitis.

Menstrual hygiene

As well as the physical and mental problems associated with mentruation, women should make sure they are adequately ‘protected’ during menstruation. Loss of blood from the vagina is involuntary and can prove embarrassing unless precautions are taken.

Clean, absorbent and easily disposable sanitary pads and intravaginal tampons are the two modern ways of dealing with the menstrual flow. The intravaginal tampon has the advantage of being inconspicuous and very efficient, and with practice can be inserted into the vagina to absorb menstrual discharge without any discomfort. Tampons are not as efficient as sanitary pads at mopping up very heavy menstrual losses. They should normally be changed around every six hours during menstruation to avoid an offensive vaginal odour.

The regular changing of tampons is also necessary to prevent a condition known as toxic shock. This condition attracted much attention at the beginning of the 1980s, but in fact it is quite rare. It results from the release of a toxin from the bacteria Staphylococcus aureus which live in the vagina.

The continuous presence of a tampon that has been forgotten and left in place at the end of a period increases the chance of the toxin entering the bloodstream and causing serious illness.