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understanding female fertility

This may sound strange, but many women today have no idea what a normal menstrual cycle is – many of them have been on the Pill for 15 years or more, so this is hardly surprising. Women often feel embarrassed that they don’t know everything about their fertility, and this lack of basic knowledge isn’t helped by the numerous myths out there about what they should and should not be doing in order to conceive successfully!

I am very fortunate to work alongside Jane Knight, who has done so much to raise awareness for women in this area of fertility. I encourage all women to attend a fertility awareness session, because even if you understand the basics, your cycle is unique to you. At our clinic, the aim is to make it easy to understand when and how ovulation occurs, without getting obsessed about it – which months of ‘charting’ can do to you. As Jane says:

An understanding of fertility – fertility awareness – is an important life skill and is every woman’s right. My work involves providing fertility – awareness sessions for both men and women. During a consultation I explain how a woman can identify the fertile ‘window’ during her menstrual cycle. I also help men to understand their own reproductive potential. Couples who understand the key concepts of fertility are in a much better position to understand how fertility declines with age and how factors may damage, reduce, enhance or optimize fertility.

Female Reproductive Organs

The primary indicator of fertility for a woman is her cervical secretions – because this relates so closely to oestrogen levels and ovulation – so we encourage women to focus on this, alongside ovulation-predictor kits or temperature charting, because it is just as important as good nutrition, relaxation and you and your partner’s health in your efforts to conceive.

A Woman’s Fertility

At birth, every baby girl is born with a full complement of immature eggs in her ovaries – around 2 million, although only between 300–400 will mature during her lifetime – which sounds as if the whole process should be pretty straightforward. But it is the maturation, release (at ovulation), fertilization and implantation of one of these eggs that results in pregnancy. No new egg cells are produced after you are born, so it’s worth thinking about what those egg cells need in order to mature successfully and produce an egg capable of being fertilized. A woman’s eggs are her most precious reserve, and need looking after.

Up until puberty, the egg cells lie dormant in the ovaries, waiting for a shift in the hormonal patterns of a girl’s body to ‘switch on’ her fertility. At what age this starts is largely influenced by genetics – if your mother started her periods early, then it’s likely you will have done, too. Starting menstrual periods is the marker of the beginning of a woman’s fertility, and is known as menarche.

In Western countries, the average age of menarche is between 12 and 14, but can be as early as 10 and as late as 16. All are completely normal. Ovulation can occur before the first period, but a girl’s early menstrual cycles can be erratic, and often without ovulation. Over the next few months, or sometimes longer, the pattern of cycles settles down to what is normal for that girl, as regular ovulation establishes itself.

If you think back to GCSE biology, you will remember the term ‘secondary sex characteristics’, which are the outward, visible signs of puberty and the onset of a woman’s fertile life. In a woman, increasing levels of FSH (follicle – stimulating hormone) and LH (luteinizing hormone) and the beginnings of oestrogen and progesterone production lead to the development of breast tissue, pubic and underarm hair, and a different distribution of body fat, all of which are designed to create a body capable of nourishing a growing baby, both before and after birth. These changes begin before the first menstrual period occurs, and can happen slowly over a couple of years, or relatively quickly. Again, this depends in part on genetics, and a mother’s experience of puberty will give some insight into what her daughter might expect.

Remember how you were warned in your sex education classes at school that sex inevitably led to pregnancy? Remember, too, all the efforts you took in the past not to get pregnant, not to mention all those false alarms? So it may feel a bit of a mystery as to why getting pregnant is now so elusive. This chapter is designed to help you understand your own fertility cycle, and how to work with it to achieve pregnancy.

Understanding Your Own Fertility

With so much misinformation about how, where, why and when, it’s always best to start with the basics. Once you are informed and familiar with your own body’s fertility indicators, you will feel more confident about managing to get pregnant.

And there is a lot of confusion out there! According to research carried out by Unipath (who produce Persona – the personal hormone-monitoring system), while 92 per cent of women accurately described ovulation, a third of them thought it occurred during a period! Out of six European countries covered in the research, the UK women surveyed had the worst knowledge of when their fertile days were: 21 per cent thought they were fertile for more than 21 days a month. And while 72 per cent of women knew that the fertile time was mid – cycle, one – third thought it possible to get pregnant at any time during their cycle.

It is essential to remember that every woman is different. Although the basic principles remain the same, what is true of your friend is unlikely to be true of you – from your cycle length to how your body indicates its fertility, to how you react physically and emotionally. This is why it is so useful to understand your own fertility.

Most women seldom think about their fertility, or menstrual cycles, but most women – when they do stop and think about it – are aware of cyclical changes to their skin, appetite, mood – all of which are indicators of their individual cycle.

The Menstrual Cycle

Most of us have learned to live with certain symptoms in our cycle, but it’s also important to remember that our fertility cycle is controlled by the pituitary gland, located deep within the brain and influenced by all activity there. Hormones, which are chemical messengers, are primarily controlled by the brain’s activity – it’s like a constant conversation that occurs between the hormones of the brain and the ovaries, sending messages back and forth (see page 8).

The pituitary gland is often referred to as the ‘master gland’ of the body, because it secretes at least nine major hormones designed to stimulate the ovaries, adrenals and thyroid, amongst others (including the testes in men), which all have a role to play in fertility. When we are producing the right amount and blend of hormones, we feel fine. When there is an imbalance, these chemical messengers can make us feel pretty lousy. We talk about having ‘hormones from hell’ when we, as women, feel imbalanced at certain times of the month. PMS is a clear indicator that hormones are out of balance. The hormones are doing their job, and the body is reacting as it should, but because the balance is out, then the effects are negative.

Each of the fertility signals that you observe when you begin to chart your own fertility corresponds to a hormonal process and the presence of hormones in your bloodstream. The hormones oestrogen and progesterone are particularly important, and both affect the body in a number of ways that are easy to note.

The menstrual cycle is a constantly changing hormonal environment, but oestrogen influences the first part of the cycle – up to ovulation – and then progesterone exerts its influence. Some women would probably prefer not to be so influenced by the ups and downs that a cycle brings, but these changing hormonal events will help you to know when your chances of conceiving are best.

Few women have a 28-day cycle, but we can say that the average length is around 28 days. For some women their normal cycle can be short (around 25 days) or long (around 35 days). Provided there is a regular pattern, this is normal for you, and you can be relatively sure that ovulation is occurring. It is when cycle length fluctuates from 25 days one month to 30 another, or 42 another, that ovulation is likely to be haphazard, or even non – existent during some cycles.

The fertility, or menstrual, cycle starts on the first day of menstruation or a ‘period’. Sometimes on medical forms women are asked to give the date of their ‘last menstrual period’ or ‘LMP’ – this would be the date on which you started to bleed.

Oestrogens are the dominant hormones during the first part of the cycle – the time before ovulation, also known as the follicular phase (see page 8) – while progesterone takes over during what is known as the luteal phase (see page 31) and also during pregnancy, should conception occur. Your cervical secretions are linked to oestrogen secretion, and can give a good indication of the availability of oestrogen.

Menstruation, or a ‘period’, is the bleeding with which every woman is familiar. It heralds the end of one cycle and the beginning of another. The hormones responsible for the activity of ovulation and womb – preparation effectively ‘take a break’ at this stage, in order to activate the next cycle. Many women are quite susceptible to the effects of this hormonal switch.

Women often ask me what’s ‘normal’ for a period: how long it should last and how much blood should be lost. The average period lasts for between 3 and 5 days, and the total blood loss is between 30 and 80 ml (6 to 16 teaspoons). However, this is only the average; each woman’s experience of her period will be unique to her. Some women seem to have a lot of abdominal cramping (caused by contractions in the womb) when they have a period, or back pain, while others have none. For some, the bleeding happens in a flood at the beginning, while for others it’s a slow, continuous bleed.

Hormones and the Phases of Your Cycle

A question I get asked all the time is, ‘How do I know if my hormones are balanced?’ Hormone balance is such an important part of a woman’s fertility, and so easily influenced by poor diet, stress, lack of sleep and environmental factors, that assessing a woman’s hormone levels – and addressing any rebalancing that needs to be done to help her achieve optimum fertility – are important aspects of the work I do. And although there are sometimes quite clear indicators of hormone imbalance, often a bit of detective work is needed.

The one major thing that will help balance hormones is a well-balanced lifestyle – which seems to be increasingly difficult for many of us to achieve these days.

A well – balanced lifestyle is important for hormonal balance because all hormone activity is an interplay between different hormones, which are the body’s chemical messengers: for example, secretion of fertility hormones will be affected if the body is producing too many stress hormones. Understanding the inter – relationship between all the hormones in the body is the first step towards achieving a positive balance.

Like all hormones, oestrogen and progesterone operate as chemical messengers, in this case controlling the length of a cycle, and ovulation, while also having an impact on other body systems. When in perfect balance, their effects are hardly noticeable, but most women have a degree of hormonal imbalance within the normal range, which makes these hormonal fluctuations more noticeable. Although the effects can vary – not just between women but also from month to month in the same woman – knowing about them and recognizing your own emotional and physical response to them are helpful when you are trying to understand your own cycle.

The Follicular (pre – ovulation) Phase

On Day 1 of the cycle, which is the first day of a period, the brain releases GnRH (gonadotrophin – releasing hormone) from the hypothalamus, which in turn tells the pituitary gland to release FSH (follicle – stimulating hormone). The levels of FSH in the bloodstream build over the next couple of weeks, stimulating follicles in the ovaries to start growing.

The follicle grows and starts to secrete oestrogen from the granulosa cells. It is the rising level of oestrogen that inhibits the secretion of FSH, while also causing ovulation. At this point, LH (luteinizing hormone) is secreted.

This first part of the cycle, the follicular or pre – ovulation phase, can vary in length. This explains why some women have longer cycles than others, and also why their cycles can sometimes be irregular.

The interplay of hormones throughout a woman’s fertile life forms the basis of her cycle. Not only do these hormones have a crucial role to play in fertility, they also have other effects on the body, which can be extremely useful when trying to define and assess your own levels of fertility. For example, progesterone has an effect on body temperature (as it’s designed to keep a fertilized egg warm in the incubator of the womb), while oestrogen has an effect on cervical secretions, which are so essential to helping achieve pregnancy.

Looking at oestrogen and progesterone individually, and also at how the subtle interplay between them and other hormones affects fertility, is the first step to understanding what is necessary for a pregnancy to happen.

Oestrogen

During the first part of the menstrual cycle, when the levels of oestrogen are rising, endorphins are also released, which are your body’s natural painkillers and ‘feel – good’ hormones, elevating mood. Many women say they feel very energized and creative during this phase.

While oestrogen has an effect on the internal reproductive organs, making the womb receptive to a fertilized egg, bringing the top of the Fallopian tube closer to the ovary and increasing its contractions to help the egg move down towards the womb, it also has other effects.

There are highly specialized cells in the cervix, for example, which produce cervical secretions, and their increased activity is directly caused by increased oestrogen. (The importance of these secretions and their role in conception is crucial, and is explained in more detail on page 18.)

Oestrogen also has an effect on libido, your sex drive. As oestrogen levels rise, so does libido – nature’s way of ensuring that sexual intercourse is welcomed close to ovulation. And when an animal is in oestrus, i.e. fertile, we refer to them as being ‘on heat’. This recognition of a link between oestrogen and heat comes partly from the effect of oestrogen on the blood vessels, causing a degree of dilation and increasing the flow of blood and its heat.

A good blood supply helps the organs of the body function properly, as nutrients are brought to cells and waste products removed. The transportation of oxygen in the blood is also important to developing cells, not least the maturing egg in the ovary. This blood supply also keeps tissues plump and supple, whether in the vagina or the tissues of the face. It is this effect that is lost after the menopause, when the lack of oestrogen causes the thinning of the skin and other tissues.

A good blood flow is beneficial to other organs, too, including the brain. Some women’s experience of increased productivity and creativity around ovulation may be explained as their own particular response to oestrogen. On the other hand, for some women this same effect provokes feelings of irritation. It just depends on how your body reacts to and copes with this powerful hormone.

Oestrogen is also essential for maintaining strong bones, as it provides the chemical ‘bridge’ that allows calcium from the diet to be used by the bones, keeping them dense and reducing porosity.