Your Pregnancy Part 1: The First Trimester
Regardless if you are pregnant with your first baby or you already have multiple little ones at home, most women have questions about what to expect in the months following a positive pregnancy test. This three-part series will cover expected changes during each trimester of pregnancy, whether differences you notice in your body or the growth and development of your growing baby. Let’s jump in with the first trimester!
Signs and Symptoms
The first trimester of pregnancy begins with the date of your last menstrual period and lasts until the end of the 13th week of pregnancy. By the time you first notice a missed period, you may already start experiencing signs and symptoms of pregnancy like nausea, breast tenderness, mood changes, fatigue, and frequent urination.
Every woman’s experience surrounding symptoms of pregnancy is different, and these symptoms can even vary from pregnancy to pregnancy. These symptoms are caused by changing levels of hormones, and they generally improve by the second semester.
Week by Week
During the first trimester, your baby is rapidly growing and developing. All human life begins as a single fertilized cell, and by the end of these thirteen weeks, your baby is about the same size as a peach! Here’s an overview of some developmental highlights during these exciting first few weeks:
Week 2: Conception occurs! All of the genetic information is already present that will determine the baby’s sex, hair and eye color, height, and other physical features.
Week 3: The embryo implants in the lining of the mother’s uterus.
Week 4: This is about the time the mother will notice she has missed her period. A hormone called hCG is being produced, which is what causes a positive pregnancy test. Baby’s brain and spinal cord are forming, and the liver is already beginning to function.
Week 5-6: Baby’s heart starts beating! Arm and limb buds are well developed by the end of week six.
Week 8: Fingers and toes are present. Baby’s nose, mouth, and ears are forming. Nerves and muscles continue to develop. Taste buds are already forming on baby’s tongue.
Week 9: All essential external and internal structures and organs are present! Eyelids are beginning to form but are closed. Bones are starting to harden.
Week 10-11: Baby can move on purpose with the coordination of the developing muscles and nerves. Baby can yawn and suck.
Week 12-13: Nails start growing on fingers and toes. Baby can be seen stretching and moving arms and legs. Baby weighs about one ounce and is the size of a peach.
You have made it to the end of the first trimester! It’s incredible to think about how much your baby has already grown in this short amount of time, and there are still two trimesters to go! Part two of this series will cover fetal development taking place within the second trimester.
If you think you are pregnant, please schedule your appointment online or call us at 612-866-7643 to speak to one of our friendly staff to schedule your appointment. First Care also offers ongoing prenatal classes to educate and support you through your pregnancy. Join us for an upcoming pregnancy or birth class!
- Understanding Pregnancy: A Comprehensive Guide. (2012). InJoy Productions, Inc.
- London, M. L., Ladewig, P. W., Davidson, M. R., Ball, J. W., McGillis, R. C., & Cowen, K. J. (2017). Maternal & Child Nursing Care (5th ed.). Boston: Pearson Education, Inc.
- Dihle, V. L. & Beck, B. G. (2016). The First 9 Months. Focus on the Family.