The short answer is “lots of things all at once!” The hormonal changes that go along with pregnancy cause changes in pretty much every part of the body with some having more of an impact and being more obvious than others.
These changes are essentially side effects of the hormones that are acting to provide for baby’s development and prepare your body for safely carrying and delivering your baby.
Also, it is important to note that different women will experience these effects to different degrees.
Skin and hair
It is normal to have an increase in the amount of pigment in the skin. This is often seen on the face (pregnancy mask), around the nipples and in the line running from your belly button to your pubic bone. As the pregnancy progresses, you may experience striae gravidarum (stretch marks) on the abdomen or breasts.
It is also normal to have an increase in hair on the face, arms, legs and area above your pubic bone.
Breasts
Breast tenderness and an increase in size are normal as the breasts prepare for milk production and supply.
Muscles and Joints
Hormonal influences and weight gain mean that there is a higher chance of back, hip and pelvic girdle discomfort which can vary in intensity and impact on daily life. Leg cramps and carpal tunnel symptoms also are not unusual.
Urinary Tract
The need to pass urine more frequently and also over night are two of the most frequent complaints regarding pregnancy. In some women, light bladder leakage also may occur as the pregnancy progresses.
Gastrointestinal Tract
Abdominal bloating, constipation and heartburn may all occur and depending on the severity, may require specific advice and treatment.
This is neither an exhaustive list of nor an explanation of the reasons behind the changes that can occur to your body during pregnancy. If you have any specific questions, it is important that you seek advice for either reassurance or treatment as may be necessary.