Pregnancy Week 5: Signs, Hormonal Changes, Fetal Growth, and More Details
At five weeks pregnant, women are embarking on a remarkable journey, as key developments and symptoms unfold during the embryonic period, which is part of the first trimester.
During this stage, the embryo, about the size of a sesame seed (0.05 to 0.1 inches long), resembles a tadpole. Critical organogenesis is underway, with the placenta and umbilical cord beginning to form, providing a vital link for transporting nutrients, oxygen, and waste between mother and baby. The neural tube, which will develop into the brain and spinal cord, is forming and typically completes by the end of this week. The baby's heart starts developing, with two heart tubes merging into one, although the heartbeat cannot be detected until around week six. The embryo is also attached to a yolk sac, which supplies nutrients during this early phase.
Common maternal symptoms include fatigue, tender breasts, mild nausea, and frequent urination, largely due to rising pregnancy hormones like hCG. Some women may not experience any symptoms at all at this stage.
As we move into the second trimester (weeks 13 to 26), the focus shifts from embryonic features to rapid fetal growth and development of sensory and motor functions. Sensory systems develop, with eyes and retina forming around weeks 16-17, ears detecting sounds around weeks 20-21, taste buds and olfactory receptors developing around weeks 14-15, and the fetus starting to respond to touch around weeks 16-17. Motor skills emerge, including swallowing, sucking, kicking, limb movements, and grasping reflexes. Fat layers and skin thicken, and vernix caseosa, a protective waxy coating, forms, aiding in insulation and protection of the fetus.
In summary, the embryonic period at five weeks involves critical organogenesis, while the second trimester milestones start later and involve more advanced fetal functions and growth. The first trimester includes weeks 5 to 12, and it is crucial to avoid certain infections during this period, as the baby is vulnerable to the effects of certain medications, illegal drugs, excessive alcohol consumption, infections like rubella, and complications from the flu.
It is recommended to start an exercise routine to help strengthen muscles for the increased workload, and the flu jab has a long safety record and is a safer option than potential complications from the flu. If you develop flu symptoms, seek medical help immediately for antiviral treatment within 48 hours. If you have questions regarding your pregnancy, contact your healthcare provider.
[1] "Pregnancy: Your Baby's Development Week by Week." Mayo Clinic. https://www.mayoclinic.org/healthy-lifestyle/pregnancy-week-by-week/expert-answers/babys-development-during-pregnancy/faq-20058145
[2] "Pregnancy Week by Week: Your Baby's Development." American Pregnancy Association. https://americanpregnancy.org/pregnancy-week-by-week/
[3] "Pregnancy: Your Baby's Development." NHS. https://www.nhs.uk/conditions/pregnancy-and-baby/pregnancy-week-by-week/
[4] "Pregnancy: Your Baby's Development." BabyCenter. https://www.babycenter.com/0_pregnancy-your-babys-development-week-by-week_10340269.bc
[5] "Pregnancy: Your Baby's Development." WebMD. https://www.webmd.com/baby/pregnancy-week-by-week#1
Science has shown that certain medications, illegal drugs, excessive alcohol consumption, infections like rubella, and complications from the flu can have adverse effects on the baby during the first trimester (weeks 5 to 12). It's crucial to avoid being blocked from receiving the flu jab, as it has a long safety record and is a safer option than potential complications from the flu. If you develop flu symptoms, seek medical help immediately for antiviral treatment within 48 hours.
