Full-term pregnancy lasts approximately 40 weeks and has three trimesters. They start on the first day after the last period. Each trimester has specific milestones for the fetus.
Although 40 weeks is the most common time, full-term babies can be born as soon as 37 weeks or as late as 42.
The Women’s HealthTrusted Source outlines the three trimesters in the following manner:
- first trimester: 1-12 weeks
- Second Trimester: 13-28 Weeks
- third trimester: 29-40 weeks
Many people also refer to the fourth Trimester , which is the 3-month transitional time after delivery.
Continue reading to learn more about each trimester of pregnancy.
Image credit: Stephen Kelly, 2018
The first Trimester
The first 12 week trusted Source trimester of a pregnancy is crucial for fetal development.
The egg and sperm are combined at conception to create a zygote. This implanted in the uterus wall. As its cells divide and grow, the zygote is transformed into an embryo.
At the end of the 12th week of the first trust Source :
- The body’s major organs have started to develop.
- The heart beats constantly.
- Fingers, toes and toes have formed.
- The length of a fetus at 3 inches (in) is approximately 1 ounce.
- Nerves and muscles are interconnected and the foetus can make fists.
- The eyelids are now closed and should remain closed until week 28. This is to protect your eyes.
A pregnant woman
During the first trimester, a person may also experience many changes.
These include trusted Source:
- tender, swollen breasts
- mood changes
- cravings for certain foods
- Urination more frequently
- weight changes
- nausea, sometimes associated with vomiting, is known as morning sick
Morning sickness can be severe in the first trimester, sometimes even beyond. Morning sickness does not happen only in the morning, contrary to its name.
Weeks 14 to 27Trusted Source are the 2nd trimester. This is a time when the fetus experiences many changes. It grows to approximately 1 foot in length and 1.5 pounds in weight.
The following will be completed by the end of the 2nd trimester:
- The first bowel movement has been developed in the intestines.
- A fetus is able to see, hear, feel, make a sucking sound, and scratch its own skin.
- The skin, hair and nails have formed.
- The lungs are still developing but they have not been able to function.
- The foetus is regularly sleeping and walking.
- The testicles of a male will have moved to his scrotum and the eggs of a female will have formed in her ovaries.
- The taste buds of have been formed.
- Bone marrow makes blood cells.
- Lanugo is fine hair that covers the body.
A pregnant woman
People often feel more at ease during the second trimester. Morning sickness and fatigue can often disappear or reduce.
Meanwhile, new changes take place:
- As the fetus develops, the abdomen expands.
- Stretch marks can appear on the abdomen and thighs, breasts, buttocks, and stomach.
- The skin around the nipples becomes darker, and the areola (the skin around the nipples) becomes darker.
- Some areas of the skin may become darker.
- Your ankles, fingers and face might swell.
- Itching can occur. It may be associated with nausea, vomiting, yellowing of the skin, or the whites of your eyes (known as jaundice). Seek medical advice.
As this trimester progresses it is possible feel the baby’s movement.
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The third trimester runs from Week 29Trusted Source to delivery, which is usually around week 40.
The majority of organs and systems in the body have been formed. They will continue to grow.
In this trimester:
- The bones are starting to harden.
- The movements of become more obvious.
- The eyes can see light and are open.
- Lung formation becomes complete.
- Lanugo is dissolved, and vernix forms.
The abdomen of the fetus is lower than normal and it usually falls head-down after delivery.
A pregnant woman
New discomfort can be caused by the growth of the foetus.
An individual might also experience
- Shortness of breath
- swelling of the feet, fingers, and face
- mood changes
- Milk leakage from the breasts
- Other breast and nipple modifications
- frequent urination
- Braxton–Hicks contractions , which don’t indicate labor
- real contractions, which indicate labor
You may also feel anxiety regarding the birth and parenthood at the end of a pregnancies.
Fourth trimester: Postpartum
The first three months following delivery are crucial for the baby’s health. This is sometimes called the fourth trimester.
This can be a very exciting time. However, there are many environmental and hormonal changes that can cause problems.
These challenges might involveTrusted Source:
- Recovering after delivery, especially if stitches are present
- Dealing with lochia is a discharge from blood and tissue that can continue for several weeks
- cramping can feel similar to menstrual cramping.
- Adjusting to a new role in parenthood
- learning new skills
- Having sore breasts or other problems related to breastfeeding
- Feeling tired, caused by a lack of sleep or other factors
- in some cases, experiencing postpartum depression
Some tips for managing include:
- Limiting visitors, if helps
- asking for assistance
- reducing housekeeping duties
- Resting while the baby does
- eat regularly, as much
- raise any concerns about the baby’s health, breastfeeding, or your personal health
- Attending all followup appointments
Anybody who experiencesTrustedSource a persistent low mood or feelings of guilt or inadequacy or thoughts about harming their baby or themselves should seek immediate medical guidance. These are signs of postpartum Depression.
If someone is at immediate risk for self-harm, suicide or hurting another person,
- The hard question: “Are You Thinking of Suicide?”
- Be open to hearing the other person’s opinion without judgment.
- To speak with a trained crisis counselor, call 911 or the local emergency line.
- Keep in touch with the person until professional assistance arrives.
- Remove any drugs, weapons or other potentially dangerous objects.
A hotline is available to help if you or someone you care about has thoughts of suicide. The National Suicide Prevention Lifeline can be reached at 800-273-8255, which is available 24/7. People who are hard-of-hearing can dial 711 or 800-273-8255 to reach their preferred relay service during a crisis.
The first few months of a newborn’s life are unique. These months are filled with new experiences, great uncertainty and upheavals as well as many emotions.
It is important to receive regular prenatal care during each trimester. A doctor can ensure that the baby is healthy and meets all developmental milestones. They can provide support and guidance.