Congratulations are in order: as of this week, your baby has officially graduated from 'embryo' to 'fetus'. The critical period of basic structural formation is ending, and the period of rapid growth and maturation is beginning. From here on out, it’s all about growing larger and fine-tuning systems.
🍼 What's Happening With Your Baby
Now the size of a cherry, your fetus has distinct earlobes, and the eyelids have fully formed. However, those eyelids will fuse shut this week and will not open again until roughly week 27 to protect the developing optic nerve.
The placenta is mature enough to start taking over the heavy lifting of hormone production from your ovaries. It is also actively passing nutrients and oxygen to the fetus and carrying waste away.
Inside the mouth, tiny tooth buds are beginning to form beneath the gums. The skeletal system, previously made of soft cartilage, is beginning to ossify (harden into bone), starting with the collarbones and jaw.
🤰 What You're Feeling This Week
If you've been suffering from severe morning sickness, hang in there: week 9 is often the peak of the summit. After this week, hCG levels generally plateau and slowly begin to drop, often bringing relief in the coming weeks.
You might notice your waistline thickening slightly. Your uterus, normally the size of a small pear, has grown to the size of a small melon. While you likely don't have a distinct 'bump' yet, tight pants may feel incredibly uncomfortable.
Heartburn and indigestion may make their first appearance this week. Progesterone relaxes the smooth muscles in your body—including the valve at the top of your stomach—allowing gastric acid to escape upward into the esophagus.
Embryo Becomes a Fetus
The embryonic stage is over. All essential organs and body parts are present. The fetal stage is defined by rapid growth and the maturation of these existing systems.
✅ What To Do This Week
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Eat smaller, slower meals — combat early heartburn by avoiding large meals, spicy foods, and lying down immediately after eating.
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Look into NIPT testing — Non-Invasive Prenatal Testing (NIPT) is a simple maternal blood draw that can screen for chromosomal abnormalities (and reveal the baby's sex) as early as week 10. Ask your doctor if you're a candidate.
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Avoid heavy lifting — relaxin, a hormone that loosens your ligaments for childbirth, is already circulating, making you more prone to muscle strains and back injuries.
"The shift from embryo to fetus means the most delicate structural work is complete. Your body has successfully built the blueprint. Now, the construction phase truly begins."
— A Note From Your Body, Week 9