Weeks 1 & 2 – Gestational Age
Your menstrual cycle has just concluded, and your body is gearing up for ovulation. Typically, ovulation occurs about 11 to 21 days after the first day of your last period. During intercourse, millions of sperm are released into the vagina, where they travel through the cervix and into the fallopian tube. If sperm successfully penetrates an egg, it forms a zygote, which contains 46 chromosomes and serves as the foundation for a new human being. The fertilized egg takes a few days to journey through the fallopian tube, dividing into cells, eventually becoming a morula. This morula transitions into a blastocyst, which will implant in the uterine lining between days 6 and 12 after conception, marking the start of the embryonic phase.
Week 3 – Gestational Age (Fetal Development – Week 1)
During this week, the embryo experiences significant growth, with initial development underway for the brain, spinal cord, heart, and gastrointestinal tract.
Weeks 4 & 5 – Gestational Age (Fetal Development – Weeks 2 & 3)
By this stage, tiny arm and leg buds are forming, and the heart starts to beat steadily. The placenta begins to develop and produce essential hormones, including hCG. Blood flow through the primary vessels starts, and the early structures that will become the eyes and ears are beginning to take shape. By the end of this period, the embryo measures about ¼ inch.
Week 6 – Gestational Age (Fetal Development – Week 4)
The lungs, jaw, nose, and palate are starting to form. The hand and foot buds now have web-like structures that will eventually develop into fingers and toes. The brain continues its complex development, and a vaginal ultrasound might detect a heartbeat at this point. The embryo is approximately ½ inch long.
Week 7 – Gestational Age (Fetal Development – Week 5)
At seven weeks, all major organs are forming within the embryo, which still weighs less than an aspirin. Hair and nipple follicles are developing, and eyelids and the tongue are beginning to take shape. The elbows and toes become more distinct as the trunk starts to straighten.
Week 8 – Gestational Age (Fetal Development – Week 6)
The ears are undergoing both internal and external formation. By this time, all adult human features are present in the embryo. Bones begin to develop, and muscles can contract. Facial features are maturing, and eyelids are more defined. The embryo is around 1 inch long, roughly the size of a bean.
Weeks 9 through 13 – Gestational Age (Fetal Development – Weeks 7 through 11)
At the ten-week mark, the embryo transitions into the fetal period. The fetus grows to approximately 3 inches in length and weighs about an ounce. Genitalia have developed into identifiable male or female forms, although they remain difficult to see on an ultrasound. Eyelids close and won’t reopen until the 28th week of pregnancy. The fetus can clench its fist, and the buds for baby teeth are visible. Notably, the head is almost half the size of the entire fetus.
If you’re considering options for conception, services like Vegas Pregnancy offer free sperm donor matching, while Make A Mom provides at-home insemination solutions, including their unique reusable option. For an insightful overview of how at-home insemination works, check out this guide. Additionally, if you’re exploring various fertility techniques, you might find our article on how fertility massage can aid in getting pregnant helpful. For more information on IVF, visit Healthline, a reliable resource for pregnancy and home insemination. For those seeking diverse family dynamics, Modern Family Blog has valuable insights on the topic.
In summary, the first trimester is a crucial period of rapid development for the embryo, laying the groundwork for a healthy pregnancy. Understanding these stages can empower you in your journey toward parenthood.