Pregnancy Trimesters

The trimesters of pregnancy mark many changes in fetal development as well as symptoms for mother. A full-term pregnancy lasts approximately 40 weeks, counting from the first date of your last menstrual period. A baby born between 38-42+ weeks is considered full term and a baby born prior to 37 weeks is considered premature. A baby that is born during the 37th week is considered early term. A premature baby can have difficulties with growth and development, as well as with digestion and breathing.

pregnancy trimesters

pregnancy test

expecting parents


First trimester (weeks 1-13)

The first two weeks of pregnancy occur before conception. Conception takes place around week 2 but varies based on the pregnant person’s menstrual cycle and when they ovulate. During ovulation, an egg is released from an ovary into the fallopian tube where it awaits fertilization. Once the egg is fertilized, it travels down to the uterus where it embeds itself into the lining of the uterus, called the endometrium. From there, the embryo begins to grow rapidly. Your hormone levels change, your heart rate increases, and your blood supply increases. A woman may begin to feel pregnancy symptoms a few weeks within conception such as nausea, fatigue, constipation, sore breasts, and headaches.

Throughout the first trimester, the baby’s organs begin to develop. It is important to stay healthy by eating nutritious foods, drinking water, and taking a prenatal vitamin as soon as possible. Folate/folic acid is an important nutrient in the beginning of pregnancy to help prevent neural tube defects. Folate is the naturally-occurring form while folic acid is the synthetic form that is typically found within vitamin supplements and fortified foods.

Your first care provider’s appointment will likely take place between 8-10 weeks, where they may do an early ultrasound, use a doppler machine to listen to heartbeat, and do blood work to check on your nutritional levels, immunity, and indicators of baby’s health. Some tests your healthcare provider may perform and/or that you may ask about include: genetic screening, nuchal translucency screening (for down syndrome, chromosomal problems, and/or birth defects), and/or chorionic villus sampling (if there is indication or belief of chromosomal problems). Remember that you do not have to consent to any testing or procedures and it’s important to speak with your provider about what these tests involve, the benefits and risks, and alternatives so that you may make an informed decision.

The risk of miscarriage is greatest during the first trimester and many expecting parents choose to wait until the end of the first trimester to announce their pregnancy, as the risk of miscarriage is reduced.

pregnancy test

Second trimester (weeks 14-26)

 Most pregnant women report feeling the most comfort and relief during the second trimester. Early pregnancy symptoms likely disappear by this time, energy levels rise, and sleep is easier to obtain. Some women may continue to experience morning sickness, possibly for the entirety of pregnancy. It can cause issues when the expecting mother is unable to keep down foods and liquids, leading to dehydration and malnutrition. An extreme form of morning sickness is known as hyperemesis gravidarum.

During this time, your belly will grow and you will soon “look pregnant”. This may be an appropriate time to start investing in maternity clothing and pregnancy/nursing bras. Along with this growth comes new discomforts such as heartburn, leg cramps, round ligament pain (felt in your abdomen/hip area as a sharp pain or tightness), backaches, congestion, and varicose veins.

Feeling movement is a pivotal moment during pregnancy and usually occurs sometime around 15-20 weeks. The first feelings of movement might be light flutters that feel like gas. The baby will begin to hear and recognize your voice during this trimester also. Try reading books to your baby or playing music to begin to bond with your baby. There have been stories or babies who develop a preference for books and music that were played to them in the womb.

The anatomy ultrasound is usually a time of great excitement for many parents and happens around 18-22 weeks. This ultrasound looks at the growth and development of the baby and this is when parents can find out the gender, if they wish. Other tests that may be suggested by your provider and/or asked for include: quadruple screen blood test, amniocentesis, blood test for anemia and antibodies, urine samples to check for UTIs or preeclampsia, and a glucose screening test to check for gestational diabetes. Remember that you do not have to consent to any testing or procedures and it’s important to speak with your provider about what these tests involve, the benefits and risks, and alternatives so that you may make an informed decision.

expecting parents

Third trimester (weeks 27-40)

The final stretch! An expecting mother may find herself feeling increasingly uncomfortable as her belly grows, weight shifts, hormones surge, and her growing baby takes up more space inside her abdomen. Some unfortunate third trimester symptoms include heartburn, frequent urination, backaches, pelvic pain, itchy skin (particularly on the abdomen), stretch marks, and possibly lactation.

This time is a wonderful time to prepare for labor and delivery by reading books and/or taking a childbirth class. You will likely begin to see your care provider more often as your due date approaches and may begin discussing your birthing plans. A written birth plan can be useful in exploring your options, making decisions, and making your wishes known in birth. It can be printed and given to your provider and/or the nurses and hospital staff present in your birthing room. It’s important to keep in mind, however, that things can change rapidly during labor and delivery, so while you may have specific birth preferences, they may only be applicable in certain situations. A birth plan can also be used to express your desires and wishes dependent on certain situations such as during a cesarean, induction, and/or epidural.

Some tests that your provider may perform or you may ask for during this trimester include: growth measurements (via fundal height and/or ultrasound), Group B Strep test, biophysical profiles, non-stress tests, and urine samples to test for UTIs or preeclampsia.


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