Being Pregnant – The 4th Week by JSB
How are your hormones?
It is important for you to know what is going on so that you can handle any changes and be able to talk about them if you have any problems. It’s also sensible to have an understanding of what is going on in your own body.
Early hormonal activity
The working of our bodies is divided up into systems which although separate, all work together. So, what affects one system often shows up in another. As we go through the series we will be looking at the changes occurring in the systems of the body when pregnant.
Our hormones are important drivers for change in pregnancy and the topic of hormones will keep recurring. This week, let’s look at some of their work in early pregnancy.
Human Chorionic Gonadotrophin (HCG) appears early in pregnancy. As early as the time of implantation in the uterine wall, the developing bundle of cells produces HCG. High levels of HCG will prevent menstruation, resulting in the first missed period. The presence of HCG also maintains the pregnancy. The level of HCG keeps rising until about 8-10 weeks of pregnancy then slowly declines until the 20 week level which remains until your baby is born.
Oestrogen always increases in the second half of the menstrual cycle and decreases if pregnancy along with the HCG does not happen. However, when pregnancy occurs, the levels of oestrogen remain high until labour is about to begin. Oestrogen encourages growth – of the uterus, breasts, of fat storage in mother and baby. Note: there are over twenty different oestrogens in your blood during pregnancy. Once the placenta is well established the ‘maternal-fetal-placental’ unit interacts to produce the oestrogens. It’s important to be aware that the mother, the baby and the placenta really do work together for the good of you, your baby, and the pregnancy as a whole.
Progesterone is produced initially under the influence of HCG and then about 6-8 weeks after conception, the placenta takes over. The production of progesterone increases steadily until 38 weeks. It has a very significant role in helping the pregnancy to continue and develop, and stimulates appetite and fat storage. It also, along with the hormone Relaxin, has a relaxing effect on muscles, joints and ligaments and helps your respiratory system to cope with the developments that are going on in your body.
There are other hormones involved in your body in pregnancy – you can’t avoid them. Over the weeks to come it is likely that others will come under discussion.
Need the loo?
Most women in early pregnancy feel the need to go to the loo to pass urine more often than normal. Usually the bladder holds urine until you are ready to go to the loo. During pregnancy, high levels of progesterone make the bladder lose its tone and it becomes more floppy. In addition in early pregnancy the enlarging uterus is still in the pelvis and pressing on the bladder. The bladder thinks it is full and sends a signal to your brain to go and empty it. It’s a bit frustrating when you then don’t have much to show for it.
Still on the subject of urine: over the weeks we find that progesterone is blamed for quite a few discomforts. This time it’s the ureters, the tubes which carry urine from the kidneys to the bladder. During pregnancy, due to the extra progesterone in the body which relaxes the sides, they get wider and longer and tend to kink. The kinking, sometimes holds up urine in the bends and this could be a possible source of infection. A good idea is to drink plenty of fluids and don’t wait too long if you want to pass urine. If you think you have a problem, tell your midwife or GP.
Baby’s growth and development
The early cardiovascular system which develops further in week four, is the first to function in the embryo. This is because by the third week of pregnancy any earlier nourishment from what is known as the yolk sac, is used up. The embryo now requires a supply of oxygen and nutrients from maternal blood through the placenta.
By the fourth week a very small heart is visible and begins to beat at around 22 days. In addition, it is able to pump blood around the embryonic blood vessels from the fourth week.
At the same time the respiratory system begins to develop, limb buds form, a layer of skin is growing and the gender is determined. In addition early kidneys and digestive system are beginning. Eyes start to develop at around 22 days and are sensitive to light from an early stage. The embryo is about 0.4 cm long and is comma-shaped. Even a very basic nervous system is forming.
About the Author
This article was written by Natural Childbirth – a great place to find your local antenatal class.