Zita West’s Guide to Getting Pregnant - Zita WEST

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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.

      Oestrogen and Signs of Fertility

      The term ‘oestrogen’ actually refers to a group of hormones that stimulate growth and strengthen tissues. Oestrogen is needed to build up the lining of the uterus so that it can nourish and sustain the fertilized egg, ensuring implantation – a crucial part of conception. When we are talking about fertility, the kind of oestrogen we are referring to is called oestradiol. Oestrogen is produced by the developing ovarian follicles and later, in increasing amounts, by the dominant follicle before the egg is released at ovulation.

      Oestrogen has many roles:

      • It signals the release of LH (luteinizing hormone), needed to trigger ovulation.

      • It is needed to build up the endometrium (lining of the womb) so that a fertilized egg can find nourishment and implant successfully.

      • It stimulates the production of cervical secretions, which are essential for the sperm to travel through the cervix to the Fallopian tube where an egg may be fertilized.

      • It causes the cervix to soften and open, making it easier for the sperm to enter the womb and reach the Fallopian tube for possible fertilization of an egg.

       Some of the signs of increased oestrogen levels, such as the amount and quality of cervical secretions, and cervical position, can be easily noticed. These signs offer some of the best indicators of your fertility status. Observing and recording your cervical secretions are vital to assessing fertility, and the optimum time for intercourse, in order to conceive (see page 21).

      Factors That Can Affect Oestrogen Production

      I often get asked how you can tell if your body is producing enough oestrogen, and what might make you oestrogen – deficient:

      • body weight 15–20 per cent below your optimum can cause menstruation to stop, and levels of oestrogen to drop

      • an excess of fibre in the diet

      • antibiotics – though occasional use is OK

      • excessive exercise

      • smoking.

      Modern women aren’t actually making more oestrogen; it’s just that today’s diet and lifestyle encourage higher levels of the hormone in the body. This is in part due to environmental oestrogens, delaying childbirth and breastfeeding, and an over – refined diet. The methods used to clear ‘old’ oestrogens from the body involve optimum digestive and liver function, which are often compromised by a poor diet and stressful lifestyle. Changing to a low – fat and nutrient – rich diet with adequate (but not too much) fibre can significantly influence the balance of hormones and help to optimize the conditions for getting pregnant.

       Equally, an excess of oestrogen can be counter – productive to conception. But take heart: there are ways round these issues – we’ll be taking a look at them in the Nutrition chapter.

      The Ovulation Phase

      The rising oestrogen level makes the hypothalamus reduce the secretion of GnRH and FSH. As the FSH decreases, oestrogen levels from the maturing follicle rise abruptly. Only then will the pituitary gland secrete LH (luteinizing hormone), which allows just one mature follicle to release an egg – ovulation.

      The Magnificent Egg

      The ovum, or egg, is the largest cell in the body – 550 times bigger than the sperm. As it matures within its fluid – filled follicle prior to ovulation, it needs a lot of energy, which is supplied by the granulosa cells (specialized cells in the ovary). These cells have two functions: to secrete oestrogen (to help the egg mature) and to nourish and feed the egg as it grows.

      The

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