1st Trimester
(Weeks 1-12)
The first trimester is the earliest phase of pregnancy. It begins on the first day of your last period and lasts until the end of the 12th week of your pregnancy. This means that by the time you find out you're pregnant, you might already be five or six weeks pregnant.
A lot happens during the first three months of pregnancy. It’s a time of great anticipation and of rapid changes for both you and your baby. This chart will show you what occurs to both the mother and baby during each trimester and will help you get ready for the months ahead.
Schedule your first prenatal visit
It is best to make your first prenatal appointment as soon as you find out that you are pregnant, ideally in your first trimester or within 42 days of joining Texas Children’s Health Plan.
Changes for Mom
- You will not have a period.
- Your breasts will be a little bigger and probably sore.
- You may have some nausea called “morning sickness”.
- You may have heartburn, gas, and possibly bloating.
- You will feel very tired.
- You will likely have mood swings.
- You will have a higher sense of smell.
- You will experience frequent urination.
Changes for Baby
- Your baby’s brain, heart, and lungs are forming.
- Your baby’s arms and legs are tiny, little buds.
- Your baby will be about the size of a grain of rice.
Changes for Mom
- You will likely gain 1 or 2 pounds. although you don't need any extra calories in your first trimester. Maintaining a healthy weight throughout pregnancy can reduce your risk of health complications.
- Your breasts will be bigger, sore, and dark around the nipples.
- You will need to urinate more frequently as your growing uterus presses against your bladder.
- You will likely feel more nausea.
- You will feel tired.
Changes for Baby
- Your baby now has a heartbeat.
- Your baby’s major organs are formed but are still developing.
- Your baby can now move his or her fingers, toes, legs and arms.
- Your baby’s face begins to develop.
- Your baby will be about as big as a raspberry – 0.6 inches long and 0.04 ounces.
Changes for Mom
- You will probably gain a few more pounds – around 2 to 4, although you don't need any extra calories in your first trimester. Maintaining a healthy weight throughout pregnancy can reduce your risk of health complications.
- You may feel hungry a lot.
- You will likely feel really tired.
- You may feel more nausea and constipation.
- You could possibly feel faint or dizzy.
- You might get headaches.
Changes for Baby
- Your baby’s mouth has 20 buds that will become teeth.
- Your baby’s fingernails and toenails are formed.
- Your baby’s skin is starting to form hair.
- You will now be able to hear your baby’s heartbeat when you visit the doctor!
- Your baby will be about the size of a plum - about 2 inches long and around 1 ounce.
Helpful tips for moms in the first trimester
Determine the hospital you will give birth to your baby at and check if your provider delivers there.
Bring a list of the prescribed and over-the-counter medications you currently take to the first prenatal appointment.
Apply for WIC, the Special Supplemental Nutrition Program for Women, Infants, and Children.
Eat healthy foods that nourish your health and baby's growth. Start taking prenatal vitamins! You can either get a prescription from your doctor or buy them over-the-counter.
What to expect during other trimesters
Get rewarded for a healthy pregnancy!
Our Healthy Rewards Program offers exciting rewards and benefits for you and your family to enjoy as we help you plan for a healthy future, such as:
Basic Baby Care and Birth Classes
Fitness Center Membership Fee Assistance
Portable Crib/Playpen
Blood Pressure Monitor (for CHIP Perinate members only)
Health Risk Assessment Reward
Prenatal and Postpartum Visit Rewards
*Restrictions and limitations may apply. Age range may vary by plan. Extra benefits valid from September 1, 2023 to August 31, 2024 .Visit healthyrewardsprogram.org for more details.
Need help applying for CHIP or Medicaid?
Our Application Assistance Specialists can help.