In this first post where you can do any of these exercises in the comfort of your own home, I have listed 3 simple exercises. All you need is a mat, wear some comfortable clothing, and most importantly, approval from your doctor that you can exercise.
At this stage, some of you may already be experiencing some form of backache. In the weeks to come, with the added weight of your tummy, there will be a tendency for the pelvis to tilt anteriorly- meaning that the front of your pelvis tilt downwards, and the back tilts upwards. (see image below of lordosis of spine and normal spine). This causes shortening in the lower back resulting in the backache. What is important, is to work the core muscles to minimise the pelvic tilt and have a good awareness of what is good posture, and good positioning of the pelvis to prevent this from happening, or at least worsening.

Image from http://jamieatlas.files.wordpress.com/2008/07/lordosis.gif
Hence why i have chosen these 3 exercises to start you off, where you get some stretch/relief in the back, learn how to postition the pelvis, and work the transversus abdominis which are the key muscles to strengthen for good pelvis positioning.
Give them a try and here’s the start to a healthy, fit pregnancy! Have fun
Cat Stretch
Goal: Stretching the back , abdominal connection
(1)
1. Come on all fours, with vertical arms, and thighs
2. Place the Spine in a neutral position, keeping length from the head to tailbone.
3. Inhale to prepare

(2)
1) Exhale and simultaneously bring the head and tailbone towards each other and round up your back
2) Inhale and send your breath into the sides and back of the ribs, expanding the ribcage as you do so.
3) Exhale and return to (1). Repeat 5-8x
Swimming Preps
Goal: Core work, balance and stability

(1)
1. Come on all fours, with vertical arms, and thighs
2. Place the Spine in a neutral position, keeping length from the head to tailbone.
3. Inhale to prepare

(2)
1. Exhale and raise arm fowards. Height of arm to be raised to depending on ability to stabilise spine, pelvis and shoulder. Lift no higher than head.
2. Inhale to return to (1)
3. Repeat 8-10x, then change to other arm

(3)
1. Exhale and raise leg towards the sky. Height of leg to be raised to depending on ability to stabilise spine and pelvis.
2. Inhale to return to (1)
3. Repeat 8-10x, then change to other leg
Squats
Goal: Balance, building strength and endurance in thighs and toning the calves

(1)
1. Stand tall with the legs in lateral rotation, with the kneecaps and toes facing in the same line of direction

(2)
2. Exhale and come down to a squat, keeping the spine tall.
3. Inhale and return to (1)

(3)
1. To tone the calves, come to the squat position and maintain that position.
2. Exhale to raise the heels off the floor, but maintaining the angle in the knees
3. Inhale to lower heels
4. Repeat 8-10x