Hormonal Changes In Pregnancy

Hormonal changes during pregnancy will cause the woman to urinate more frequently. This settles down after about three months, but later in pregnancy the size of the uterus puts pressure on the bladder, and frequent urination occurs once again.

A close up of a belly showing a pigmented vertical line on skin from the belly button

Hormonal changes in pregnancy can cause pigmentation changes in the skin

Some women develop dark patches on the forehead and cheeks called chloasma, which are caused by hormonal changes affecting the pigment cells in the skin. This can also be a side effect of the contraceptive pill. The navel and a line down the centre of the woman’s belly may also darken. These pigment changes fade somewhat after the pregnancy but will always remain darker than before.

After the pregnancy has been identified, the woman should see her doctor at about ten weeks of pregnancy for the first antenatal check-up and referral to an obstetrician. At this check-up she is given a thorough examination (including an internal one), and blood and urine tests will be ordered to exclude any medical problems and to give the doctor a baseline for later comparison.

Routine antenatal checks are then performed by the midwife, general practitioner or obstetrician at monthly intervals until about 34 weeks pregnant, when the frequency will increase to fortnightly or weekly. Blood pressure and weight measurement and a quick physical check are normally performed. A small ultrasound instrument may be used to listen for the baby’s heart from quite an early stage. Further blood tests will be performed once or twice during this period, and a simple test will be carried out on a urine sample at every visit. An ultrasound scan is usually performed to check on the size and development of the foetus.

Most women are advised to take tablets containing iron and folic acid throughout pregnancy and breastfeeding, in order to prevent both the mild anaemia that often accompanies pregnancy, and nerve developmental abnormalities in the foetus.

As the skin of the belly stretches to accommodate the growing baby, and in other areas where fat may be found in the skin (such as breasts and buttocks), stretch marks in the form of reddish/purple streaks may develop. These will fade to a white/silver colour after the baby is born, but unfortunately they will not normally disappear completely.

About the fourth or fifth month, the thickening waistline will turn into a bulge, and by the sixth month, the swollen belly is unmistakable. The increased bulk will change the woman’s sense of balance, and this can cause muscles to become fatigued unless she can make a conscious effort to maintain a good upright posture. Care of the back is vitally important in later pregnancy, as the ligaments become slightly softer and slacker with the hormonal changes, and movement between the vertebrae in the back can lead to severe and disabling pain if a nerve is pinched.

Pregnant lady lying in a grassy meadowDuring pregnancy, the mother must supply all the food and oxygen for the developing baby and eliminate its waste materials. Because of these demands, the mother’s metabolism changes, and increasing demands are made on several organs. In particular, the heart has to pump harder, and the lungs have more work to do supplying the needs of the enlarged uterus and the placenta. Circulation to the breasts, kidneys, skin and even gums also increases. Towards the end of the pregnancy, the mother’s heart is working 40% harder than normal. The lungs must keep the increased blood circulation adequately supplied with oxygen.

As the mother is the baby’s sole source of nourishment during pregnancy, she should pay attention to her diet. A balanced and varied diet containing plenty of fresh fruit and vegetables, as well as dairy products (calcium is required for the bones of both mother and baby), meat and cereals, is appropriate.

During the last three months of the pregnancy, antenatal classes are very beneficial. Women are taught exercises to strengthen the back and abdominal muscles, breathing exercises to help with the various stages of labour, and strategies to cope with them. Women who attend these classes generally do far better in labour than those who do not.

In the month or so before delivery, it will be difficult for the mother to get comfortable in any position, sleeplessness will be common, and the pressure of the baby’s head will make passing urine a far too regular event. Aches and pains will develop in unusual areas as muscles that are not normally used are called into play to support the extra weight, normally between 7 and 12 kg (baby + fluid + placenta + enlarged uterus + enlarged breasts), that the mother is carrying around.

Attending lectures run by the Nursing Mothers’ Association (or similar organisations) to learn about breastfeeding, how to prepare for it and how to avoid problems, is useful in the last few weeks of pregnancy and for a time after the baby is born.

Visiting the hospital or birthing centre that you have booked into for the confinement can be helpful, so that the facilities and the labour ward will not appear cold and impersonal when they are used.

After the baby is born, visits to a physiotherapist to get the tone back into your abdominal muscles and to strengthen the stretched muscles around the uterus and pelvis will help the woman regain her former figure.

(Last modified: 9th Oct 2014)

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