A woman’s body goes through many changes during the whole pregnancy period. Its like transform into another body.
Some of these changes are visible, such as weight gain, big belly and some are emotion such as morning sickness, etc.
If you look at the last months of pregnancy you will find that at that time a woman’s body has enough space for the baby and for herself, of course.
1. Change in the uterus during pregnancy
Uterus provides a protective and nutritive environment to the fetus.
In the first trimester, the uterus is small and start grows up inside pelvis.
The tissues which made uterus grow in the first 20 weeks and increase the weight 500 g to 1 kg. Now it cannot fit in pelvic and come side the pelvic and situated between navel and breast.
After this, it will not grow but stretches. Its height becomes from 7 to 30 cm, width from 5 to 23 cm and depth from 3 to 20 cm.  
2. Changes in the Cervix during pregnancy
Cervix is the entrance to your womb and situated between vagina and uterus. If you try to touch it, it will feel like donut shape inside the vagina.
Cervix can also help you in detecting ear;y pregnancy. If you are pregnant it feels softer than before.
Cervix doesn’t change throughout the pregnancy. but it becomes softens in late pregnancy in response to become painless contraction. 
3. Changes in Vagina during pregnancy
During pregnancy, the vagina changes color blue from pink due to increased blood flow. But it will disappear after pregnancy.
Increased blood flow and a higher level of estrogen, progesterone, and oxytocin can make the vagina more sensitive toward sexual arousal.
As blood flow increases to the vagina it pH alter and it will smell different like the doughy scent and its taste also become metallic and salty. [4 ][ 6]
In very early pregnancy your vagina will start to discharge fluid to keep cervix safe.
During pregnancy, your vagina becomes susceptible to yeast infection.
All these effects will not last long, these will go away as a baby come.
4. Change in the posture of the mother during pregnancy
Pregnant women posture start shifting in the second trimester because as baby grows mother’s body start to make room for baby.
Mother’s backs start to curve and shoulder may move back
Pregnant women posture become bigger. Abdomen shapes change from flat or concave to convex.
Some women abdomen is muscle separate. Women’s fetus puts a large strain on women’s body.   
5. Changes in body weight
Woman gets approximately 2 kg in the first 20 weeks after that 500g weight per week if we see in total women can get approximately 9-12 kg weight during the whole pregnancy.
While underweight women who get pregnant can get up to 18 kg during the whole pregnancy.
Women can get 1 to 2 kg in the first weeks and ½ kg the rest of the months.
If you are expecting a twin then you can get up to 20 kg throughout pregnancy. 
But net weight gain thought the pregnancy depends upon bodyweight of the mother. If mother underweight she will gain more weight than normal and overweight mother gets less weight than normal.
6. Changes in the cardiovascular system
In the cardiovascular system, we generally consider the heart and blood vessels.
All tissues and cells of this system transfer all the nutrients and oxygen to the fetus and also take out the waste product and carbon dioxide.
During pregnancy cardiac output, vascular volume, and heart rate increased. cardiac workload increase by 40% to 50% in the third trimester.  
Several complex changes occur in the Cardiovascular system during pregnancy.
- The workload on the cardiac system increase on the heart
- Blood volume also increases by 30-50%.
- Circulation of oxygen is increased by 18%.
7. Changes in Blood pressure during pregnancy
Drop-in blood pressure is very common in early pregnancy. Blood vessels dilated due to hormonal changes which leads to lower in blood pressure.
Blood pressure starts to fall down and reach the lowest point somewhere in the middle of the second trimester.
That’s why women feel dizzy in early pregnancy.
Lying on the flat back can result in a sudden drop in blood pressure and loss of consciousness because enough oxygen will not reach the brain. 
8. Swelling during pregnancy
During pregnancy body water increases by 7- 8 liter, 2-3 liters of which are interstitial and rest of are extracellular. 
The swelling should only be on foot and ankles. This is A combination of a slight increase in the permeability of the capillaries the downward force of gravity and weight of uterus down the rate of flow of blood to the heart and due to gravity extra fluid on your body will sink in water.
Result in Fluid collects in the tissue of feet and leg of women. After the first trimester, if the fluid not absorbed by the blood circulation then this cause swelling called edema. It will be more likely to occur in a later stage.
9. Respiratory changes
Physical changes due to the growing fetus and hormonal changes can affect the respiratory tract too.
Chest changes shapes due to pushes by uterus and increases in size from front to back.
During the pregnancy air volume increase by 50% due to the rate of breathing increase slightly and each breath contain a larger volume of air.
The lung capacity of filling air decreased during pressure on the diaphragm from the fetus this happens in late pregnancy. Cause of these changes women can feel difficulty in breathing as pregnancy progress to childbirth.   
10. Change in the urinary system
The kidney must work extra hard to extract waste from the blood and those from fetus to convert into the urine.
A woman needs to pee more often than normal. In late pregnancy, women often have to get up in the night to urinate. Because as pregnancy progress fetus also grow and put pressure on the bladder. This reduces the storage capacity of the bladder and women have pee more often.  
11. Skin changes
Woman’s appearance of the skin changes during the pregnancy such as dark spots, stretch marks, acne, melasma, etc.
In some pregnant women, brownish pigmentation of the skin covers the face which also called chloasma.
Stretching of the skin occurs over the maximum growth breast, thighs and in the abdomen. About 80-90% of women will develop stretch marks.  
This can cause stretch marks, but this will gradually disappear after delivery.
Women’s sweat gland activated during the pregnancy, which causes sweats more than usual and can cause acne. 
12. Change in the breast
In early pregnancy, the breasts may feel tingly or swollen. In fact, this is the first sign of the pregnancy caused by the elevation of hormones.
The dark area around the nipple increases.
As first trimester mid is coming, your breast starts getting bigger. The breast may itchy due to changes in the breast.
The surface of blood vessels on the breast may become visible due to increased blood flow.
Nipples and the surrounding area grow and become darker in color.
As pregnancy progresses you breast may start to leak yellow liquid.   
13. Oral problem
More children women have more likely she will lose her teeth. It is also found in a study in 2008 by the American Journal of Public Health. In this study found ages between 35 to 49 with one child women lose an average of 2 teeth.
Other dental-related problems including enlarged gums or bleeding from gum may be the cause of increased blood flow.
- NCBI “Sex and Pregnancy: A Perinatal Educator’s Guide” “https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1595041/”
- NCBI “[Cardiovascular changes during pregnancy].” “https://www.ncbi.nlm.nih.gov/pubmed/12756474”
- NCBI “Edema in pregnancy.” “https://www.ncbi.nlm.nih.gov/pubmed/9185112”
- AJPH “Edema in pregnancy.” “https://ajph.aphapublications.org/doi/full/10.2105/AJPH.2007.124735”
- Lumen “Changes to the Mother’s Body During Pregnancy” “https://courses.lumenlearning.com/boundless-ap/chapter/changes-to-the-mothers-body-during-pregnancy”
- Family doctor “Changes in Your Body During Pregnancy” “https://familydoctor.org/changes-in-your-body-during-pregnancy-first-trimester/”
- Healthylifenu “Stages of Pregnancy: Changes in Mother’s body & Fetus during Trimesters” “https://www.healthylifenu.com/stages-of-pregnancy/”