First Trimester of Pregnancy: Symptoms & More

by John Staughton (BASc, BFA) last updated -

The first trimester of your pregnancy is one of the most critical times for your baby’s development, but it is also a time of significant changes in your body. Knowing what to expect is critical so none of the changes take you by surprise.

What is the First Trimester?

The first trimester is made up of the first three months of your pregnancy, so from weeks 1-12, your body will be preparing for the baby that is beginning to grow. Even before formal tests or ultrasounds can confirm that you are pregnant, your body will be working in overdrive. Some women are unaware of their pregnancy during part of these first twelve weeks, due to a late confirmation of pregnancy, but the changes that are occurring in your body are difficult to miss.

Closeup picture of a woman holding her belly.

Trust your gut and call the doctor if you are worried. Photo Credit: Shutterstock

First Trimester Symptoms

In the first trimester, you will experience a wide range of changes – physical, emotional, hormonal, and physiological, among others. Some of the most common first trimester symptoms include cramping, bleeding, stomach distention, constipation, fatigue, tender breasts, increased urination, vaginal discharge, food cravings, and heartburn.


Cramping is normal during the first trimester, as the body will begin to change shape to prepare for the extra room needed by the baby. This may be similar to the cramping you feel before your menstrual period typically begins.

Nausea and Vomiting

More than 80% of women will experience nausea in their first trimester, and while it doesn’t always end in vomiting (morning sickness), this is one of the most well known and reliable indicators of pregnancy. [1]


Some bleeding in the first trimester is normal, particularly in the first 5-12 days, which is when the egg will be implanted in the wall of the uterus. Bleeding beyond that, or more regularly, could be a sign of a more serious complication, and should be discussed with your doctor. [2]


When your body first realizes that you are pregnant, your progesterone levels will soar. This is a hormone that can also help relax you and put you to sleep, so fatigue is natural. Eating more food and carrying around more weight can also lead to feelings of tiredness in the first three months of pregnancy. [3]

Tender Breasts

Breast tenderness is common, as your mammary glands will be changing in response to hormones. Your breasts will need to begin producing milk to feed your baby, and will likely swell in size. This can cause tenderness and the need for a larger cup size, in some women. [4]


You will likely begin urinating more often in the first trimester since your body is also producing more blood. More blood and fluid in the body means that your kidneys will be pulling out more liquid waste, which will need to be eliminated from the body. [5]


Vaginal discharge is a normal symptom during your first trimester, particularly if it has a milky white consistency. This is actually the residue of fluid that keeps your vagina clear of any pathogens. Discharge that has a foul smell or a color other than white should be discussed with your doctor. [6]


Food aversions and unexpected cravings are experienced by many women in the first trimester; as long as the food you’re eating (or eliminating) doesn’t affect your diet negatively, feel free to eat your pickles and peanut butter all you want. [7]


Your stomach may look or feel distended in the first few months of pregnancy as your abdominal cavity shifts and changes. This can lead to constipation and stomach discomfort, but it should lessen in your second and third trimesters. [8]

Aches and Pains

Your body works very hard during pregnancy, and you will need to be supporting another life both physically and nutritionally for nine months. This can take a toll on your back, knees, ankles, shoulders, and buttocks, among many others, but these aches and pains are normal. [9]

First Trimester Week- by- Week

To get a full picture of the first trimester – and know what to expect – it is best to go week by week and cover the major developments during pregnancy.

Week 1: Technically, your first week of pregnancy begins on the first day of your last period, but if you are trying to get pregnant, prenatal vitamins are a great option for this first week.

Week 2: In the second week, your ovulation cycle will begin, meaning that it is an ideal time to have sex if you are trying to get pregnant. Be sure to stay active and begin looking for a midwife or specialist.

Week 3: You may or may not be pregnant, depending on whether fertilization occurred successfully, but you should maintain a normal diet and try not to take any medications unless they are prescribed or absolutely necessary.

Week 4: This will typically be the week that you can first get a positive pregnancy test, which you may have taken in response to the fatigue, cramping, nausea or breast tenderness that you have already begun to experience. [10]

Week 5: You won’t see any notable physical changes yet, but your baby is growing. Set up an appointment to see a doctor for 3-4 weeks in the future, as this will be an ideal time for a checkup to make sure the pregnancy is progressing normally.

Week 6: By this point, symptoms like nausea, aches and pains, fatigue, and hunger pangs may have already begun. Avoid the use of cigarettes and alcohol, and cut back on caffeine intake as much as possible.

Week 7: Around this time, nausea and hunger become much more noticeable, so don’t worry if your morning sickness and cravings for snacks suddenly spikes. [11]

Week 8: This is a common week for an ultrasound to check for normal development; if that procedure goes well and heartbeat is detected, miscarriage risk drops significantly. [12]

Week 9: As your baby grows in size, incontinence issues may begin, which may require more attention or the use of pads on a daily basis.

Week 10: Despite only being an inch long at this point, your baby’s organs will be developing already, and some of your first trimester symptoms will start to abate.

Week 11: Your baby’s genitals will begin to develop, meaning that a gender determination could be close at hand. Also, chromosomal tests can be done around this time to ensure normal development. [13]

Week 12: You may begin to show around the 3-month mark as your baby begins a period of rapid growth. This is also when many expecting mothers decide that it is safe to tell friends and family – since miscarriage is far less likely in the second trimester. Protection Status
About the Author

John Staughton is a traveling writer, editor, publisher and photographer with English and Integrative Biology degrees from the University of Illinois in Champaign-Urbana (USA). He co-founded the literary journal, Sheriff Nottingham, and now serves as the Content Director for Stain’d Arts, a non-profit based in Denver, Colorado. On a perpetual journey towards the idea of home, he uses words to educate, inspire, uplift and evolve.

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