One of the most exciting and nerve-wracking things about pregnancy is watching your baby grow and develop. Fetal growth is a gradual process that occurs week by week, and there are many different factors that can influence it. In this article, we’ll explore the stages of fetal growth week by week and discuss what you can expect as your baby develops.
Table of Contents
Week 1: Conception
The first week of fetal growth is actually the week of conception. This is when the sperm and egg come together to form a single cell, which will eventually develop into a complex human being. At this point, the fertilized egg is called a zygote, and it begins to divide rapidly as it travels down the fallopian tube towards the uterus.
Week 2: Implantation
During the second week of fetal growth, the zygote reaches the uterus and implants into the lining of the uterine wall. This process can cause some mild cramping and spotting, but it usually goes unnoticed. Once the zygote is implanted, it begins to develop into an embryo.
Week 3: Embryonic Development
During the third week of fetal growth, the embryo begins to take shape. The head and spinal cord form first, followed by the heart and circulatory system. The embryo also develops the beginnings of its digestive system and respiratory system, as well as tiny buds that will eventually become arms and legs.
Week 4: Organ Development
By the fourth week of fetal growth, the embryo has grown to about the size of a poppy seed. This is when the major organs begin to form, including the brain, kidneys, liver, and lungs. The heart also begins to beat, although it’s still too early to hear with a stethoscope.
Week 5: Limb Development
During the fifth week of fetal growth, the embryo’s arm and leg buds begin to grow and form joints. The fingers and toes are also starting to take shape. At this point, the embryo is about the size of a sesame seed.
Week 6: Facial Features
By the sixth week of fetal growth, the embryo’s facial features are becoming more defined. The eyes and ears are taking shape, and the nose and mouth are starting to form. The brain is also developing rapidly, with billions of neurons forming every day.
Week 7: Growth Spurt
During the seventh week of fetal growth, the embryo goes through a growth spurt. It doubles in size and its organs and systems continue to develop. The arms and legs are getting longer, and the fingers and toes are more defined.
Week 8: Fetal Period Begins
At the end of the eighth week of fetal growth, the embryo officially becomes a fetus. This marks the beginning of the fetal period, which will last for the remainder of the pregnancy. The fetus is now about an inch long and weighs less than a gram.
Week 9-12: Rapid Growth
During weeks 9-12 of fetal growth, the fetus experiences rapid growth and development. It’s now about the size of a plum, and all of its major organs and systems are in place. The fetus also develops fingernails, toenails, and hair, and its movements can now be felt by the mother.
Week 13-16: The Second Trimester
The second trimester of pregnancy begins at week 13 and lasts until week 28. During this time, the fetus continues to grow and develop rapidly. It’s now about the size of an avocado, and its movements are becoming more coordinated. The fetus also begins to develop its sense of hearing and can hear the mother’s voice and other sounds from outside the womb.
Week 17-20: Gender Reveal
By week 17-20 of fetal growth, the fetus is about the size of a sweet potato. This is when many parents choose to find out the sex of their baby through ultrasound. The fetus’s skin becomes less transparent, and its hair and nails continue to grow.
Week 21-24: Lung Development
During weeks 21-24 of fetal growth, the fetus’s lungs begin to develop in preparation for breathing air. The fetus is now about the size of a cantaloupe, and its movements are becoming more pronounced. The fetus also begins to develop sleep-wake cycles and may respond to external stimuli like light and sound.
Week 25-28: Viability
By week 25-28 of fetal growth, the fetus is now considered viable, which means it has a chance of surviving outside the womb with medical intervention. The fetus is about the size of an eggplant and weighs around 2-3 pounds. Its eyes can now open and close, and it may even have hiccups.
Week 29-32: Fetal Position
During weeks 29-32 of fetal growth, the fetus settles into a head-down position in preparation for birth. It’s now about the size of a squash and weighs around 4-5 pounds. The fetus’s bones are becoming harder, and its movements may be less frequent but more forceful.
Week 33-36: Final Preparations
During weeks 33-36 of fetal growth, the fetus is getting ready for birth. It’s now about the size of a honeydew melon and can weigh up to 6 pounds. The fetus continues to gain weight, and its organs and systems are preparing for life outside the womb.
Week 37-40: Full Term
By week 37-40 of fetal growth, the fetus is considered full term and is ready to be born at any time. It’s now about the size of a watermelon and can weigh up to 9 pounds. The fetus’s movements may slow down as it prepares for delivery.
Conclusion
Fetal growth is an amazing and complex process that occurs week by week throughout pregnancy. By understanding the different stages of fetal development, you can better appreciate the incredible journey that you and your baby are on together. If you have any concerns about your baby’s growth or development, be sure to talk to your healthcare provider.