Pregnancy, or gestation, is a period of around 9 months when an unborn baby is developing in the uterus. The first sign of pregnancy is usually missed menstruation, but there are also other signs.
Pregnancy involves changes that will significantly impact a woman’s body. Most pregnancies last for about 280 days, but they can last anywhere from 37 to about 42 weeks, starting from the first day of the last period.
Doctors divide pregnancy into three stages, or trimesters, during which specific changes occur. Each trimester lasts for around 3 months.
A pregnancy calculator can help to predict when a baby is likely to be born.
Read on to learn more about what to expect during pregnancy.
Nausea is common in early pregnancy.
Apart from missing a period, other early signs of pregnancy include:
nausea, with or without vomiting
breast changes, such as tenderness
Nausea is common during the first 3–4 months of pregnancy, while many women experience tiredness during the first and last trimester.
To confirm a pregnancy, a woman can:
see a doctor
take a home pregnancy test
A pregnancy test detects the human chorionic gonadotropin (HCG) hormone in the blood or urine. HCG is present just a few days after becoming pregnant.
Levels of the hormone are low at the beginning of pregnancy, and they gradually increase. Having a high level of HCG can signal multiple pregnancies, for example, having twins or triplets.
If a home pregnancy test is positive, see a healthcare professional for confirmation. They can provide this by conducting an abdominal or transvaginal ultrasound scan.
The scan can confirm:
the gestational age of the pregnancy
how many embryos there are
whether the placement is correct in the womb
The doctor can also ensure that a person receives proper advice and support from the start of pregnancy.
After confirming the pregnancy, the healthcare professional often recommends taking a multivitamin supplement that contains folic acid. If the pregnancy is planned, the doctor may recommend taking folic acid ahead of conception.
What happens in pregnancy: Conception
A home pregnancy test can show if a person is pregnant, but a doctor should confirm the result.
Conception occurs when sperm from a male penetrates an egg from a female and fertilizes it. This usually happens in the woman’s fallopian tube after ovulation. The result is a zygote — a unified sperm and egg cell.
The zygote immediately starts to divide, forming a cluster of cells called an embryo.
After 5–7 days of dividing and growing, the embryo attaches to the wall of the womb, or uterus, and puts out root-like veins called villi. This process is called implantation.
The villi ensure that the embryo is anchored to the lining of the uterus. They will eventually become the placenta, which feeds and protects the embryo or fetus as it develops, supplying it with oxygen and nutrition, and expelling waste.
Home pregnancy testing kits are available for purchase online.
The first trimester runs through the first 12 weeks. The embryo develops quickly at this stage.
A woman will probably experience:
an increase in urination, due to hormonal changes and increased blood flow through the kidneys
During this time, the fetal bones, muscles, blood, nervous system, and most of the internal organs start to form.
When these are complete, the embryo is known as a fetus.
By this point, the fetus measures about 1 inch in length, the ears and facial features are evident, and the fingers and toes are starting to appear.
The fetus develops inside the uterus, surrounded by amniotic fluid. This is the “water” that “breaks” just before delivery.
Toward the end of the first trimester, the doctor will recommend some tests, including follow-up ultrasound scans, to check on the baby’s health and development.
During the third trimester, antenatal classes will prepare you for what to expect during labor and after delivery.
The third trimester lasts from week 29 until birth. The baby will build up stores of fat, and the lungs and senses of hearing, taste, and sight will develop further.
The mother may experience back pain and find it more difficult to rest comfortably. She will also urinate more often, due to the pressure on her bladder. In addition, indigestion can result when the fetus pushes against the stomach.
Early contractions can occur days or weeks before birth, and doctors call these Braxton–Hicks contractions. They do not indicate labor.
Many hospitals offer antenatal classes, which provide information about giving birth and how to care for a newborn, including tips on breastfeeding.
Pregnancy trimesters: A guide
Click here for more detail on what to expect in each trimester.
It is important to keep in touch with healthcare providers throughout pregnancy.
The first visit
The initial appointment usually occurs within the first 12 weeks of pregnancy.
A doctor will take note of the mother’s general health and any issues that may require care or treatment. They will also advise about healthful living during pregnancy.
A healthcare provider will describe local pregnancy care services and any available financial assistance.
They will weigh the mother, check her blood pressure, and test her urine for signs of infection and other abnormalities. They may also perform a physical exam and Pap smear.
Also, a doctor usually recommends an ultrasound scan. This uses sonic waves to produce an image of the fetus and predict the birth date. It can also show if there are multiple pregnancies.