GUIDE
Your baby is the size of a lime — and the risk of miscarriage has dropped significantly.
Week 12 is one of the most reassuring milestones in early pregnancy. The risk of miscarriage falls dramatically after a confirmed heartbeat at this stage. The fetus is developing reflexes — it can squint, open its mouth, and curl its toes. The first-trimester screening window for the nuchal translucency scan is closing, and many people choose this week to share their pregnancy news.
Be prepared from day one
Your baby is about the size of a lime — roughly 5.4 centimeters (2.1 inches) from crown to rump and weighing about 14 grams (half an ounce). The fetus has more than doubled in size over the past three weeks.
Reflexes are the headline this week. The nervous system has matured enough to drive a range of involuntary responses. The fetus can now squint, open its mouth, make sucking motions, and respond to touch. If the sole of its foot were stimulated, the toes would curl. These reflexes are essential practice for the movements and functions the baby will need after birth.
The face is now fully formed. All the features — eyes, nose, mouth, ears — are in their proper positions. The eyes have moved from the sides of the head to the front, giving the fetus a more human appearance. The eyelids are fused shut and will remain so until about week 26-28.
The intestines, which had been partially developing within the umbilical cord due to limited space in the tiny abdomen, have now fully migrated back into the abdominal cavity. The bone marrow is beginning to produce white blood cells, building the earliest foundations of the immune system. The pituitary gland at the base of the brain is starting to produce hormones.
The placenta is now fully functional, having taken over hormone production from the corpus luteum. This transition is a key reason why many first-trimester symptoms — especially nausea — begin to improve around this time.
For a look at what happened last week, see our week 11 guide.
Week 12 often feels like a turning point. The combination of decreased miscarriage risk, potentially improving symptoms, and an approaching announcement milestone gives many pregnant people a renewed sense of optimism and excitement. If you have been holding off on sharing the news, our guide on when to announce your pregnancy can help you decide the right timing.
Your uterus is now about the size of a softball and has risen above the pelvic bone. Your provider can feel it during an abdominal exam, and you may notice a small, firm bump in your lower abdomen — especially at the end of the day when bloating adds to the appearance. This is often the week when pregnancy starts to become visible, at least to you.
Nausea may be noticeably better, though it does not disappear overnight. For many people, the improvement is gradual — less intense nausea, fewer food aversions, longer stretches of feeling normal. Some people continue to have nausea into weeks 14-16, and a small percentage deal with it throughout pregnancy. If nausea is still severe and interfering with your ability to eat and drink, talk to your provider about adjusting your treatment plan.
Your blood pressure is likely at its lowest point in pregnancy around weeks 12-16. This is normal and caused by progesterone relaxing blood vessel walls, but it can cause dizziness when you stand up quickly. Rise slowly from sitting or lying down, and stay hydrated.
Every pregnancy is different. You may experience all, some, or none of these symptoms.
This week is about wrapping up first-trimester screening, planning your announcement, and beginning to look ahead to the second trimester.
The NT scan window closes at 13 weeks 6 days. If you have opted for first-trimester combined screening (NT scan plus blood work) or NIPT, make sure these are done by the deadline. Ask your provider when to expect results — NIPT results typically take 1-2 weeks, while NT scan results may be available immediately.
Many people feel comfortable sharing the news after the 12-week milestone. Think about how you want to tell family, friends, and your workplace. You are not obligated to tell anyone on any particular timeline — this is your news to share when and how you want.
While you do not have to disclose your pregnancy to your employer at any particular time, planning ahead can reduce stress. Review your company's parental leave policy, check FMLA eligibility (12 months of employment, 1,250 hours worked), and understand your short-term disability benefits if applicable.
While you may not need a full maternity wardrobe yet, your regular pants may be getting tight. Belly bands, hair-tie waistband tricks, or a few pairs of maternity jeans or leggings can make the transition more comfortable. Many people find they transition to maternity clothes gradually between weeks 12 and 20.
When in doubt, call your provider. No question is too small during pregnancy.
Next week, your baby's vocal cords will be forming, fingerprints will be becoming truly unique, and many people choose this week to announce their pregnancy to the wider world. You are nearly at the second trimester.
Next up: Week 13. If you are still waiting on screening results, our NIPT guide can help you understand what to expect. For managing the transition out of first-trimester symptoms, see pregnancy fatigue. For a full overview of everything the first trimester covers, read our first trimester guide. And if early pregnancy anxiety has been weighing on you, our miscarriage signs and support guide addresses common fears with facts.
This guide is for informational purposes only and is not a substitute for professional medical advice. Always consult your healthcare provider with any questions about your pregnancy.
