Things to Know in Your First Trimester of Pregnancy

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Things to Know in Your First Trimester of Pregnancy

Things to Know in Your First Trimester of Pregnancy

What to Expect in Your First Trimester of Pregancy

Everyone gets blissful about their big baby news — but a little confused about what will happen, when and how. Here’s the short of what will happen over the first trimester of your pregnancy.

For most, the more they know about any new endeavor, the more comfortable and confident they feel. However, for some this is the planning process of all planning processes!

In simple words, the dates for the first trimester considered are the first day of your last period until weektwelve. It is the earliest phase of pregnancy and a time of rapid changes for both you and your baby. (Mayo Clinic, 2020)

Things to know in First Trimester about Baby Development Week by Week

The baby’s development changes a lot during the first trimester, rapidly developing from the first hints of life into a peach-sized fetus. Here are some things to expect:

Week 1: Any woman may have a sense of conception, but the truth is that pinpointing the exact moment pregnancy begins can be difficult. This is also the reason any pregnancy is considered to begin on the first day of the last period.

Week 2: The next step is fertilization which takes place when sperm meets up with one of the eggs and combines to create a new life at the chromosome level. This whole process of fertilization determines physical characteristics like eye color, hair color, and even biological gender in the womb.

Week 3: During this week the fertilized egg moves through the fallopian tube to the uterus and then the body begins producing enough human chorionic gonadotropin (hCG) to disrupt the menstrual cycle, and pregnancy tests turn positive.

Week 4: From this week onwards the embryo splits in two creating the placenta and starts delivering nutrients and oxygen to the baby throughout pregnancy. During this stage of development, the brain, spinal cord, and backbone form the baby.

Week 5: Though still tiny at this point, the baby is still developing rapidly. This week the baby’s shape becomes more distinct as it separates into three layers—the ectoderm, endoderm, and mesoderm—through which your baby’s organs, skin, and nerves grow.

Week 6: This week, the baby’s bones grow, arms, legs, hands, and feet may be noticeable in sonograms and the heart finds its rhythm—usually around 150 beats per minute, twice as fast as an adult’s. (WebMD, 2020)

Week 7: During this week baby’s facial features begin to form, with evidence of ears and a mouth and dark spots for the eyes and nostrils.

Week 8: At this point the baby has quadrupled in size and the brain directs the intentional movement of limbs.

Week 9: At this stage, the baby’s organs have developed a bit and continue to grow. The baby’s head will be half the length of the body and the heartbeat will become stronger and more regular.

Week 10: Congratulations! By the end of this week, you will officially have a fetus and can see adorable fingers and toes.

Week 11: This week, the baby will have a growth spurt and double in weight. Some 3D scans can even show smiling babies!

Week 12: The first bowel movement of the baby may occur this week and one could feel a lot of stretching, kicking, and wiggling. It’s proof that you carry life within and is exciting for new parents.

 Physical Changes in the First Trimester

Every woman’s earliest pregnancy symptoms are different from each other, some women swear that they could immediately tell they had conceived although some women don’t realize they are pregnant for a long time. (BabyList, 2021)

Whenever it happens, at some point, every woman starts to feel different as a result of hormonal changes.

Here’s a little bit of what you might experience during the first trimester. But remember, everyone’s first trimester can feel different, so try not to compare yourself to anyone else!

  • PMS-like feelings or symptoms
  • Tender breasts
  • Constipation
  • Excess discharge
  • Tiredness and fatigue
  • Food likes and dislikes
  • Oops! moments or excess peeing
  • Heartburn
  • Mood swings
  • Morning sickness
  • Weight gain

First Trimester To-Do’s and Don’t List

It’s important for a woman to be aware of what to do and what to avoid while pregnant to take care of yourself and your baby. (Parents, 2021)

What to do – Here are suggestions of personal health measures to take during the first trimester:

  • Take prenatal vitamins after consultation with the doctor
  • Mild exercise regularly
  • Follow a diet high in fruits, vegetables, low-fat forms of protein, and fiber
  • Drink lots of water and add extra calories (about 150-200 calories more than normal)

What to avoid – These things should be avoided during the first trimester:

  • Strenuous exercise or strength training could cause an injury or pain in the stomach
  • Strictly avoid alcohol, caffeine, smoking, and illegal drugs
  • Smoked or raw seafood, especially shellfish
  • Raw sprouts and unpasteurized milk or other dairy products

 Emergency Symptoms During the First Trimester

Below are a few of the symptoms that could be a sign that something is seriously wrong and needs emergency attention by the doctor.

  • Severe abdominal pain
  • Heavy bleeding
  • Severe dizziness
  • Rapid weight gain or too little weight gain


Congratulations on the start of your journey into motherhood! We hope the information in this post has given you some insight into the next few weeks of your new life with your baby. You’ve still got a long way to go on the journey, so be gentle with yourself and focus on self-care. A new baby is exciting and knowing what to expect up front is a good way to gauge when a visit to the doctor or ER is required.

Work Cited

“1st Trimester Pregnancy: What to Expect.” Mayo Clinic, Mayo Foundation for Medical Education and Research, 26 Feb. 2020, 

Bhargava, Hansa D. “First Trimester of Pregnancy: What to Expect, Baby Development.” WebMD, WebMD, 16 July 2020, 

“First Trimester of Pregnancy.” Babylist, Jan. 2021, 

“Your First Trimester of Pregnancy, Week-by-Week.” Parents, Feb. 2021, 

# Tags:
First Trimester of Pregnancy, Pregnancy, Women’s Health
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