Weeks and Trimesters Your Pregnancy Week by Week Guide Your Pregnancy Week by Week Guide Overview First Trimester Week 1 Week 2 Week 3 Week 4 Week 5 Week 6 Week 7 Week 8 Week 9 Week 10 Week 11 Week 12 Week 13 Second Trimester Week 14 Week 15 Week 16 Week 17 Week 18 Week 19 Week 20 Week 21 Week 22 Week 23 Week 24 Week 25 Week 26 Week 27 Third Trimester Week 28 Week 29 Week 30 Week 31 Week 32 Week 33 Week 34 Week 35 Week 36 Week 37 Week 38 Week 39 Week 40 Week 3 of Your Pregnancy By Holly Pevzner twitter linkedin instagram Holly Pevzner is an award-winning writer who specializes in health, nutrition, parenting, and family travel. Learn about our editorial process Holly Pevzner Medically reviewed by Medically reviewed by Andrea Chisholm, MD on July 31, 2020 facebook twitter linkedin Andrea Chisolm, MD, is a board-certified OB/GYN who has taught at both Tufts University School of Medicine and Harvard Medical School. Learn about our Review Board Andrea Chisholm, MD Updated on August 27, 2020 Print Verywell / Bailey Mariner Table of Contents View All Table of Contents Baby Development Symptoms Self-Care Tips Advice for Partners Recommended Products Special Considerations Next in Your Pregnancy Week by Week Guide Week 4 of Your Pregnancy Conception! Even though the start of your pregnancy journey began two weeks ago at week 1, the start of your baby’s development begins this week. While you won’t know if you’re officially pregnant until the end of week 4 or in week 5, during week 3, a new little life is beginning to take form. Which Trimester? First trimester How Many Weeks to Go? 37 weeks Your Baby's Development at 3 Weeks Fertilization, or the joining of the egg and sperm, is the first step in your child’s development. This week the fertilized egg grows from a one-cell zygote into a ball of cells called a blastocyst. From zygote to blastocyst, your tiny baby measures 0.1 mm–0.2 mm (100–200 microns), or about the size of the head of a pin. Verywell / Bailey Mariner The 10 Best Cloth Diapers of 2021 Growing and Dividing After fertilization, the egg is called a zygote. The zygote begins to divide from one cell to two, then two to four, and then four to eight, and so on. As it does, it travels through the fallopian tube to the uterus—a journey that takes three to five days. Once in the uterus, and about five days after fertilization, the ball of cells becomes a blastocyst. What About Twins? During week 3 development, one baby can become two. Identical twins come from the same egg and sperm with the same genetic material. The fertilized egg can split into two identical groups of cells at different stages, such as the two-cell stage or the blastocyst stage. But, it usually happens during the first week after conception. Fraternal twins are another possibility this week. Fraternal twins do not come from the same egg and sperm. It takes two eggs and two sperm to have fraternal twins. So, if you release two eggs during ovulation and each egg is fertilized by different sperm, then you’ll have two separate zygotes or fraternal twins. Stay Calm Mom: Episode 1 Watch all episodes of our Stay Calm Mom video series and follow along as our host Tiffany Small talks to a diverse group of women and top doctors to get real answers to the biggest pregnancy questions. 6:08 Am I Pregnant? Real Women Share Their Early Signs Your Common Symptoms This Week Even though a lot is going on in your body right now, it isn’t anything you can truly feel. During week 3, you can’t tell that you’re pregnant yet, and you don’t necessarily have any physical symptoms. Emotions You may, however, be experiencing some emotional symptoms. As you think about the beginning of this new journey, it may fill you with excitement. Or, you may feel nervous and anxious as you wait to take a pregnancy test. Of course, you can go back and forth between emotions or even experience them all at the same time. It is all very normal. Pregnancy can be an emotional roller coaster, even this early. Spotting When your tiny baby reaches your uterus, it will find a spot to attach or implant into the uterine wall. As it burrows in, it sometimes causes a small amount of bleeding or spotting. If you do not see any spotting around the time of implantation, it doesn’t mean you aren’t pregnant. Not all women have this symptom. What Experts Say “The blood is a natural byproduct of the embryo burrowing into the uterine wall and delicate, new blood vessels breaking apart.”—Allison Hill, MD, OB/GYN Implantation and implantation spotting are more likely to take place next week, during week 4. However, it can happen as early as six days after ovulation, so at the very end of week 3. Self-Care Tips Weeks 3 and 4 of pregnancy are a bit of a waiting game. Continue to care for yourself by trying to eat well, getting in some activity, and staying positive. Work on Your Diet Start or continue to add healthy foods to your daily diet to get all the nutrients you need to nourish your body and a growing baby—especially iron and folate. Keep Taking Those Vitamins It’s not always easy to get all the nutrition you need through your diet, so start or continue to take prenatal vitamins. Vitamins aren’t a substitution for healthy eating, but they do help fill in the gaps. Get a Little Exercise Staying active can help you maintain a healthy weight, give you energy, boost your mood, and reduce stress. The American College of Obstetricians and Gynecologists (ACOG) recommends 150 minutes of physical activity per week. But don’t overdo it. And, don’t forget to talk to your doctor before starting an exercise program if you have any health concerns. Use Positive Affirmations As you prepare physically for pregnancy, you can also prepare mentally. Positive affirmations are thoughts and phrases that you repeat to yourself. They can help you overcome any fear or anxiety you have as you wait for a pregnancy test. Try saying something like, “My body is ready and capable of nourishing a baby.” It certainly doesn’t hurt to think positively. Your Week 3 Checklist Get some fresh air and exercise. Continue taking prenatal vitamins. Try some positive affirmations. Research potential healthcare providers. Resist taking a home pregnancy test. Advice for Partners Now is a good time for partners to encourage healthier lifestyle choices by participating in them. Go grocery shopping together to pick out some healthy meal choices and cook them together. Get some fresh air, go for a walk, and spend time engaging in physical activities you both enjoy. Stay away from alcohol and other harmful substances together. It’s easier to make good choices and stick with the changes when you support and encourage each other. Upcoming Doctor's Visits You may visit a doctor’s office or lab for a blood test to confirm a positive home pregnancy test during week 5. Your doctor may schedule your first prenatal visit between week 6 and week 8. Recommended Products You might be looking for information this week as you wait to find out the news. Take a look at some pregnancy books and consider purchasing a home pregnancy test to have on hand when it’s time to test. Pregnancy Tests It’s too early to take a home pregnancy test in week 3. But, by the middle or later part of next week, you might be able to detect the pregnancy hormone hCG in your urine with a sensitive early test. The 8 Best Pregnancy Tests of 2021 Pregnancy Books Pregnancy books can provide information, tips, answers to questions, and even a little humor. Some books are a great resource to help ease your mind, and others are fun and relatable when you need a good laugh. The 10 Best Pregnancy Books of 2021 Special Considerations Week 3 puts you between ovulation and taking a pregnancy test. That leaves you with a little time on your hands. The wait might be easy or a little stressful. Try to resist the temptation to take an early test. Instead, stay busy by researching healthcare providers, getting together with friends, or doing things you enjoy. Choosing a Healthcare Provider Again, there’s no need to schedule a prenatal appointment just yet. However, if you haven’t decided on a doctor or a midwife, you can use this time to further scope out what sort of healthcare provider you’d like to see throughout your pregnancy. Ask local friends and family who’ve recently had a baby for their recommendations. Next, make some appointments with a few practitioners. Tell them you’re in the market for a new provider and that you’d like to have an initial meeting to get to know them and ask questions. What Experts Say “Don’t be afraid to hold your OB/GYN or midwife to a high standard. Right now, you might not even know what’s important to you. As your pregnancy progresses and you learn more about your options, you may discover that the provider you selected does not fit your ideals any longer—and that’s OK.” —Allison Hill, MD, OB/GYN The 2-Week Wait The two-week wait between ovulation and taking a pregnancy test can be exciting, but hard. If you’ve been trying to conceive for a while or you’re undergoing fertility treatments, the two-week wait can feel like an eternity. You might obsess and analyze every twinge and tingle looking for any sign of pregnancy. You might spend a lot of time worrying about all the “what-ifs.” Excitement, anxiety, and worry are all normal emotions, but it’s important to try to manage them. Keep busy and find ways to distract yourself when the worries return. Talk about your feelings with your partner, then do something fun together. Or, reach out to your friends or an online group to help you get through the long days of waiting. Taking a Pregnancy Test Pregnancy tests detect human chorionic gonadotropin (hCG). This pregnancy hormone rises quickly in your body after implantation, but during week 3, it is too early to detect hCG. Even the most sensitive tests will not pick up the pregnancy hormone until sometime next week. What Experts Say “It’s hard to wait. Uncertainty can be very anxiety-provoking, but there’s something to be said for accepting your lack of control. It can actually be a great relief.” —Shara Marrero Brofman, PsyD Testing too early is unreliable as it can lead to a false result. If it’s negative, it doesn’t mean that you aren’t pregnant—it could just be too early to tell. You can avoid that disappointment if you wait a little longer. If you are undergoing fertility treatments, testing too early can result in a false positive. The test can pick up hCG leftover from your trigger shot. It doesn’t mean you are pregnant, and it doesn’t mean you aren’t. It means you have to test again later when the time is right. It can be tough to wait, but the best time to take a pregnancy test is after you miss your period. A Word From Verywell Week 3 brings the amazing dawn of new life. You can’t feel it or see it yet, but it’s making its way to your uterus, where it will find the perfect spot to call home for the next 37 weeks. Implantation may take place at the very end of this week, but it’s more likely your tiny creation will attach and begin the next stage of growth next week. The end of week 4 also brings the possibility of a positive early home pregnancy test. Week 4 of Your Pregnancy Was this page helpful? Thanks for your feedback! Get diet and wellness tips to help your kids stay healthy and happy. Sign Up You're in! Thank you, {{form.email}}, for signing up. There was an error. Please try again. What are your concerns? Other Inaccurate Hard to Understand Submit Article Sources Verywell Family uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Hill, MA. Zygote. Embryology. Updated April 12, 2020. Niakan KK, Eggan K. Analysis of human embryos from zygote to blastocyst reveals distinct gene expression patterns relative to the mouse. Dev Biol. 2013;375(1):54-64. doi:10.1016/j.ydbio.2012.12.008 Kyono K. The precise timing of embryo splitting for monozygotic dichorionic diamniotic twins: when does embryo splitting for monozygotic dichorionic diamniotic twins occur? Evidence for splitting at the morula/blastocyst stage from studies of in vitro fertilization. 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J Clin Psychiatry. 2013 Aug;74(8):786-92. doi:10.4088/JCP.12m08083 Fonseca AL, Koyama J, Butler EA. The role of family of origin in current lifestyle choices: A qualitative secondary data analysis of interracial and same-race couples. Fam Community Health. 2018;41(3):146-158. doi:10.1097/FCH.0000000000000188 Gourevitch RA, Mehrotra A, Galvin G, Karp M, Plough A, Shah NT. How do pregnant women use quality measures when choosing their obstetric provider?. Birth. 2017;44(2):120–127. doi:10.1111/birt.12273 Cole LA. The hCG assay or pregnancy test. Clin Chem Lab Med. 2012;50(4). doi:10.1515/cclm.2011.808 Morse JE, Calvert SB, Jurkowski C, Tassinari M, Sewell CA, Myers ER. Evidence-based pregnancy testing in clinical trials: Recommendations from a multi-stakeholder development process. PLoS One. 2018;13(9):e0202474. doi:10.1371/journal.pone.0202474 Additional Reading Allison Hill, MD. Email communication. October, November 2017. Artal-Mittelmark, R. Stages of Development of the Fetus. Merck Manual Consumer Version. Merck Shark & Dohme Corp. 2019. Reproductive and Placental Research Unit. Twins. Yale School of Medicine. Shara Marrero Brofman, PsyD. Email and Phone Communications. October, December 2017.