Читать книгу Zita West’s Guide to Getting Pregnant - Zita WEST, Zita West - Страница 50

While oestrogen dominates the first phase of your cycle, progesterone dominates your second, post – ovulatory or luteal phase of your cycle. Before ovulation, progesterone is present only in small amounts. After ovulation, progesterone, produced by the corpus luteum, is present in higher amounts.

Progesterone has many roles:

• It makes the lining of your uterus soft and spongy, with increased blood flow, so that a fertilized egg can latch on to it and implant.

• It is needed to support and continue a pregnancy by ensuring that the lining of the womb remains intact and a woman doesn’t have a period.

• It also causes your Basal Body Temperature (BBT) to rise after ovulation so that it is measurable with a BBT thermometer.

Although some women choose to record their waking temperature, many of the women I see get so stressed out by this method that I do not normally recommend it. Nor is this method recommended by new NHS guidelines – for three reasons:

1. Progesterone causes a rise in BBT (that is, waking temperature – your temperature after you have been resting for at least three hours and before you get out of bed).

2. Your temperature does not rise until AFTER ovulation – by which time it is too late to try to conceive.

3. It can be very stressful having a daily reminder when you first wake up that you are not pregnant yet.

As I said earlier, generally I would not advise women to record their temperature. There may be an appropriate role for taking your temperature if you have been advised by a trained fertility awareness practitioner that this would be beneficial – for example to provide a more objective marker and to determine the length of the luteal phase of your cycle. Otherwise – don’t worry about it.

Having said this, taking their temperature does give some women reassurance that they are ovulating. Trying this for a month when you are first trying to conceive will do no harm, but not month in, month out – it causes too much stress. Many factors affect your temperature – a low – grade fever, alcohol, fewer than three hours’ sleep, air travel and electric blankets – so it’s really not the best indicator.

Because progesterone is the hormone designed to prepare the body for pregnancy, birth and breastfeeding, its effects are linked to these processes. Breasts tend to swell a little under its influence, and can become tender for many women during the second phase of their cycle (and during early pregnancy, if it occurs).

Progesterone also has an effect on muscles in the body, for example in the gut, making digestion less efficient. This can make some women more prone to constipation (another common problem for many women during pregnancy).

In addition, the progesterone effect on smooth muscle affects the ligaments, which soften. This is in preparation for labour, when the ligaments of the pelvis have to soften for the bones to ‘give’ a little during birth. Although this is not so extreme as during pregnancy, some women find they are more susceptible to minor injuries after ovulation, when progesterone levels are raised.

Some women whose blood pressure is naturally low may find these combined effects of progesterone can cause them to feel a bit faint, or more tired, in the run-up to their period. Ensuring an adequate intake of fluids, while avoiding those with diuretic effects like colas, coffee and large quantities of tea, can help with this.