Pregnancy can be different from woman to woman, and even for the same mother from one pregnancy to the next. Some symptoms of pregnancy last for several weeks or months, while other discomforts are temporary or don’t affect all women.  

A normal pregnancy usually lasts about 40 weeks, counting from the first day of a woman’s last menstrual period, which is about two weeks before conception actually occurs. pregnancy is divided into three trimesters. Each of these periods lasts between 12 and 13 weeks. 

During each trimester, changes take place in a pregnant woman’s body as well as in the developing fetus, and a summary of these changes will be described below. 

Conception and implantation

About two weeks after a woman has her period, she ovulates and her ovaries release one mature egg. The egg can be fertilized for 12 to 24 hours after it’s released as it travels down the Fallopian tube toward the uterus. 

If an egg meets up with a sperm cell that has made its way into the Fallopian tube, it combines into one cell, a process that’s known as fertilization or conception. 

At fertilization, the sex of the fetus is already determined, depending on whether the egg receives an X or Y chromosome from a sperm cell. If the egg receives an X chromosome, the baby will be a girl; a Y chromosome means the baby will be a boy. 

First trimester (weeks 1-12) changes in the mother's body

A woman will experience a lot of symptoms during her first trimester as she adjusts to the hormonal changes of pregnancy. In the early weeks, the pregnancy may not be showing much on the outside of her body, but inside many changes are taking place.  

For example, human chorionic gonadotrophin (hCG) is a hormone that will be present in a woman’s blood from the time conception occurs. Levels of hCG can be detected in a woman’s urine about a week after she has a missed period, and it is why a woman will have a positive result on pregnancy test 

Other hormonal changes can contribute to pregnancy symptoms: Rising levels of estrogen and hCG may be responsible for the waves of nausea and vomiting known as morning sickness that a woman typically feels during her first few months of pregnancy. Despite its name, morning sickness can occur any time of day. 

A woman will also feel more tired than usual during the first trimester, a symptom that’s linked with rising levels of the hormone progesterone, which increases sleepiness. She may also need to urinate more frequently as her uterus grows and presses on her bladder. 

Early in pregnancy, a woman’s breasts will feel more tender and swollen, another side effect of rising levels of pregnancy hormones. Her areolas, the skin around each nipple, will darken and enlarge.  

A pregnant woman’s digestive system may slow down to increase the absorption of beneficial nutrients. But reduced mobility of the digestive system might also trigger such complains  as heartburn, constipation, bloating and gas

Many parts of the body will work harder during pregnancy, including a woman’s heart. Her heartbeat will increase to pump more blood to the uterus, which will supply it to the fetus.  

As more blood circulates to a woman’s face, it will give her skin a rosier complexion, described as a “pregnancy glow.” 

Besides the physical changes in a woman’s body, she may also experience emotional highs and lows in the early months of her pregnancy and throughout it. These emotions may range from weepiness, mood swings and forgetfulness to fear, anxiety and excitement. 

Second trimester (weeks 13-27) changes in the mother's

By the second trimester, some of the unpleasant effects of early pregnancy may lessen or disappear as a woman’s body adjusts to its changing hormone levels. Sleeping may get easier and energy levels may increase. 

Nausea and vomiting usually get better and go away. But other symptoms may crop up as the fetus continues its growth and development. 

Women feel more pelvic pressure, like something is weighing it down. 

A more visible baby bump appears as the uterus grows beyond a woman’s pelvis

As the fetus is getting bigger and a woman is gaining more pregnancy weight in the front of her body, she may also experience more back pain

Sometime between the 16th and 18th weeks of pregnancy, a first-time mother may feel the first fluttering movements of the fetus, known as quickening

The 20th week usually marks the halfway point of a woman’s pregnancy. 

third trimester (weeks 28-40) changes in the mother's body

during the third as a woman’s enlarged uterus pushes against her diaphragm, a major muscle involved in breathing, she may feel short of breath because the lungs have less room to expand,Her ankles, hands, feet and face may swell as she retains more fluids and her blood circulation slows. 

A mother-to-be will need to pee more frequently because more pressure will be placed on her bladder. She may also have more backaches and more pain in the hips and pelvis, as these joints relax in preparation for delivery. 

Her face may develop dark patches of skin, and stretch marks may appear on her belly, thighs, breasts and backside. She may also notice varicose veins on her legs. 

In the third trimester, a woman’s breasts may experience some leakage of colostrum a yellow liquid, as they get ready for breastfeeding. The baby will drop lower in her abdomen.