Week 3 of Pregnancy
Your baby is about the size of a lentil
Your Baby This Week
Development milestones for week 3
Week 3 is when conception typically occurs, and it is nothing short of miraculous. If sperm and egg met during your fertile window, fertilization has happened and your baby began as a single cell that immediately started dividing. Within hours, that one cell becomes two, then four, then eight. By the end of this week, your baby is a ball of about 70-100 cells called a blastocyst, smaller than a grain of sand. This tiny cluster is already differentiated - the outer layer will become the placenta, while the inner cell mass will become your baby. Around days 6-10 after fertilization, this blastocyst reaches your uterus and begins implanting into your uterine lining. This is the moment pregnancy truly begins. At 3 weeks pregnant, everything is happening at the cellular level, completely invisible and undetectable, but absolutely extraordinary.
Your Body This Week
Changes you may experience
At 3 weeks pregnant, most women feel completely normal - and this is one of the most frustrating aspects of early pregnancy. You are in the infamous "two week wait" (TWW), that agonizing period between ovulation and your expected period where you have no idea if conception occurred. Your body is producing progesterone regardless of pregnancy, which can cause symptoms like breast tenderness, bloating, mild cramping, and fatigue - the same symptoms you get before your period. This is why "symptom spotting" during the TWW is such a trap: everything feels like it could be a pregnancy sign, but nothing is definitive. Around the end of week 3, some women experience implantation - you might notice very light spotting (pink or brown, not red) or mild cramping as the embryo burrows into your uterine lining.
Tips & Advice for Week 3
Practical guidance from real moms
The two-week wait is psychological torture, according to countless women who have been through it. Here is what experienced veterans recommend: stay busy. Schedule activities, dive into hobbies, binge a new show - anything to prevent obsessive symptom-checking. Resist the urge to test too early; implantation does not occur until 6-12 days past ovulation, and even then, hCG needs time to build to detectable levels. Testing before 10 DPO (days past ovulation) often leads to false negatives and unnecessary heartbreak. Continue taking your prenatal vitamins and avoiding alcohol and raw foods - act as if you are pregnant even though you do not know yet. Some women find comfort in the mantra: "Today, I might be pregnant." It acknowledges the uncertainty while allowing space for hope.
Medical Guidance for Week 3
What to discuss with your healthcare provider
There is nothing medically actionable during week 3 - no test can detect pregnancy this early, and no appointment is needed. Continue your prenatal vitamins and healthy habits. If you experience severe cramping or heavy bleeding later in the week, contact your doctor as this could indicate an ectopic pregnancy or other complication. Otherwise, try to be patient and take care of yourself.
Disclaimer: For educational purposes only. Consult your healthcare provider for personalized medical advice.