You will go through many hormone changes during pregnancy. Progesterone and oestrogen levels increase, stopping your menstrual cycle, and prolactin levels instigate changes in your breasts. Your breasts may be tender during the first trimester especially, as they begin to change. Their weight and shape alters as fatand milk-producing tissue is formed. Have your bra size measured regularly and wear a supporting bra (but not an underwired bra, as it can restrict natural movement).

Pregnancy hormones will also have an affect on your bladder and it is quite normal to need to go to the toilet more often. Don’t try to compensate for this by cutting down on fluids, however, because you will need additional fluids during exercise. You may also find that you retain more fluids and notice swelling in your legs, ankles and feet. Exercise will help with this by increasing circulation and fluid movement. Also, try not to stand for long periods, and elevate your legs whenever possible.

At the beginning of pregnancy, as your hormones begin to change, your blood vessels become more elastic and relax (vasodilation). Because at this early stage you have the same amount of circulating blood, there is actually too little to fill the blood vessels (vascular underfill). The result of these changes is that you may feel dizzy and faint, especially when getting up from the floor or a gym bench. During this stage, try to avoid exercises which involve prolonged standing and, when you get up from floor work, do so in stages. Turn onto your side, wait a few seconds, then push up onto your hands and knees and wait. Bring one foot through so you kneel on one knee, and finally move to standing slowly, again taking a few seconds to ‘get your bearings’ (see exercise 83, opposite).

From the point of view of abdominal exercise, it is the hormone relaxin which is the most important. This hormone is normally produced in your ovaries and breasts, but during pregnancy additional amounts come from the placenta and the lining of your uterus (endometrium). It is released from about week two in pregnancy and its effects can stay in your body for up to five months after childbirth. During pregnancy the relaxin hormone softens connective tissue within the body by increasing the amount of water taken up by the collagen fibres within this tissue. The result of this softening is to allow the joints of the pelvis (sacrociliac at the back and pubis at the front) to ‘give’ a little so that the pelvis can expand to allow childbirth. The softening does not just affect the pelvic joints, however, but all of the joints in the body. For this reason you must be cautious with high-impact activities and intense stretching.

We have seen that your uterus is increasing in size throughout pregnancy. This results in changes to your abdominal cavity or ‘balloon’ (see fig. 14.2a, page 174). The weight of the uterus is supported at the bottom of the cavity by the ligaments and muscles making up your pelvic floor (see fig. 14.2b). The uterus ‘hangs’ within the pelvis supported by the round ligaments positioned at either side attached to the front of the pelvis, and the broad ligament attached from the uterine sac to the lumbar spine. The increasing size and weight of the uterus stretches the ligaments and may give discomfort in the lower abdomen. This can be eased by keeping the pelvic floor muscles strong and practising core stability exercises.

Begin lying on your back on a mat.

Keeping your body horizontal (do not sit up) turn onto your right side (b), and then onto your front (c). Push with your arms to press your hips backwards (d), bending your knees to come up to a kneeling position (four point kneeling, hands and knees on the ground). Draw your right foot and leg forwards (e) and place your right foot flat on the floor (half kneeling, one knee on the ground). Place both hands on top of your right knee and press downwards on the knee to propel yourself to standing. Bring your feet together (f).

As you bring your right foot forwards and press onto your knee, try to keep your shin bone (tibia) vertical with a 90 degree angle at your knee. This will position the force of your push along the shin bone and give you better leverage to push into standing.

If you feel dizzy moving from lying to standing, pause at each position change and allow your breathing to settle before moving onto the next position.