At 9 weeks the embryo is about 23 mm — grape-sized — with fully formed eyes and the beginnings of facial expression. For you, this is often the hardest week of the first trimester, and there is a straightforward reason why.
The short answer: hCG peaks somewhere between weeks 8 and 11, and nausea follows it, which is why week 9 is frequently the worst and why things usually improve from week 12 to 14. Baby has formed eyes sealed under eyelids, working facial muscles and first swallowing movements. If you cannot keep fluids down for a day, that is hyperemesis and it needs treating, not enduring.
Your baby this week
The eyes are now fully formed, complete with a lens and retina, but sealed shut by fused eyelids that will not open again until around week 26. The face has become recognisably human: a distinct nose, a mouth, and facial muscles that are beginning to contract.
Those working muscles produce the first swallowing movements, and taste buds are developing on the tongue. Later in pregnancy, flavours from what you eat pass into the amniotic fluid, which is how taste preferences begin forming before birth.
The tail that was visible a few weeks ago has gone. Arms can bend at the elbow, fingers and toes are no longer webbed, and tiny movements happen constantly — still far too light to feel. The embryonic period is drawing to a close and the fetal period begins around week 10.
Your body this week
hCG is at or near its highest, and almost everything you are feeling traces back to it. Nausea and vomiting are typically at their most severe now. It is worth knowing that this is a peak: hCG falls after about week 11, and most women notice real improvement between weeks 12 and 14.
Your metabolic rate has risen, which is why you may feel hot, flushed and uncomfortable in rooms that suit everyone else. Reflux and heartburn often begin around now too, because progesterone relaxes the valve between the stomach and the oesophagus — lying down straight after eating makes it markedly worse. Our heartburn guide covers which antacids are appropriate in pregnancy.
Gums may still be swollen and prone to bleeding. Keep using a soft brush and see a dentist if you have not already.
Tests and appointments
If your booking appointment has not happened, it should be imminent. A urine test for asymptomatic bacteriuria is a standard part of it, and it matters precisely because there are no symptoms — progesterone relaxes the ureters and slows urine flow, making silent infection more common in pregnancy and more likely to reach the kidneys if untreated.
✅ Worth doing this week
- Do not lie down for 1–2 hours after eating — the single most effective change for reflux
- Eat whatever stays down. A week of plain carbohydrates is not a nutritional emergency; dehydration is
- Sip fluids constantly rather than drinking a glass at once, which is more likely to come back up
- Track how many times a day you vomit — it is the number your doctor will ask for
- Ask about anti-sickness medication if you are struggling; it exists and is used in pregnancy
When to call your doctor
Call the same day if: you cannot keep any fluid down for 24 hours, are passing very little or very dark urine, are losing weight, feel faint on standing, or have bleeding, severe or one-sided abdominal pain, or a temperature above 38°C. Persistent vomiting is hyperemesis gravidarum — a treatable condition, and the usual reason women end up needing intravenous fluids is that they waited too long.
FAQ — 9 weeks pregnant
Why is nausea worst at 9 weeks?
hCG peaks between roughly 8 and 11 weeks, and nausea tracks it closely. That is why week 9 is, for many women, the worst of the pregnancy — and also why it usually starts easing from around week 12 to 14 as hCG falls. Knowing there is a peak rather than an endless climb is genuinely useful when you are in the middle of it.
How big is the baby at 9 weeks?
About 23 mm crown to rump — roughly a grape. The eyes are fully formed but sealed shut by eyelids that will not open until the second trimester, the facial muscles are starting to work, and the first swallowing movements begin.
When does morning sickness need treating rather than enduring?
When you cannot keep fluids down for 24 hours, are losing weight, are passing much less urine or it is very dark, or are vomiting many times a day. That is hyperemesis gravidarum territory, and it is a treatable medical condition, not a character test. Anti-sickness medication is available and used in pregnancy. Contact your doctor rather than waiting for the next appointment.
Why do I feel hot all the time?
Your metabolic rate rises in pregnancy and your blood volume is expanding, so you generate and carry more heat — flushes and feeling warm when everyone else is comfortable are common. Dress in layers, keep fluids up, and remember that a raised core temperature from outside sources like hot tubs is a different thing and still worth avoiding this trimester.
Week 9 at a glance
At 9 weeks the embryo is about 23 mm — grape-sized — with fully formed eyes sealed under fused eyelids, working facial muscles, developing taste buds and the first swallowing movements. The tail has gone and fingers are separate. For you, hCG is at its peak between roughly weeks 8 and 11, which is why nausea is often at its worst right now and why it usually eases from weeks 12 to 14. A raised metabolic rate explains feeling constantly hot, and progesterone relaxing the stomach valve explains reflux. Inability to keep fluids down for a day is hyperemesis and needs treatment.
Inside Baby Novum: the symptom journal records nausea and vomiting frequency day by day. That turns a vague account into the specific number a doctor needs to decide whether medication or fluids are warranted.