12 Weeks Pregnant — Baby Is the Size of a Lime
At 12 weeks you are 84 days into the 40-week count, with 196 days to go and 30% of the pregnancy behind you. Baby is about the size of a lime and weighs about 1.5 g. This page fixes week 12 in place: what is developing, which appointments are still ahead, and how the week maps onto months.
30% of 280 days. The due date itself is a midpoint, not a deadline: full-term births spread across roughly weeks 37 to 42.
This week
Reflexes are developing and tiny fingernails are growing. This is the window for your NT scan (11–13 weeks).
Measured in months, week 12 sits in month 3: The end of the first trimester brings the dating scan and the NT screening, and for many people the nausea starts to lift.
Appointments still ahead
| Window | Appointment | What it checks |
|---|---|---|
| 15–20 wks | Quad / anomaly blood screen | Optional blood test for screening risk factors. |
| 18–22 wks | Anatomy scan | Detailed look at baby's organs, limbs and growth — often the sex reveal. |
| 24–28 wks | Glucose tolerance test | Screens for gestational diabetes. |
| 28–34 wks | Routine growth checks | Regular midwife visits, bump measurements and blood pressure. |
| 34–36 wks | Group B strep swab | A simple swab that protects the baby during delivery. |
| 37–40 wks | Weekly checkups | Position checks, growth checks and the birth plan in earnest. |
Around week 12
| Week | Size | Weight |
|---|---|---|
| 11 | a fig | about 1.2 g |
| 12 | a lime | about 1.5 g |
| 13 | a lemon | about 1.8 g |
Frequently asked
What does 12 weeks pregnant mean in days and months?
12 weeks is 84 days since the first day of your last period, which is about 3 months pregnant on the four-week-per-month convention. 196 days remain in the 40-week count from here — that is 30% of the way through.
How big is a baby at 12 weeks?
Around the size of a lime, at about 1.5 g. These are population averages: a scan measurement that differs by a few days is normal and does not by itself mean anything is wrong.
Which trimester is week 12?
The 1st trimester. The split used here is the same one the calculator applies: the first trimester covers days 1–90, the second 91–195, and the third from day 196 onward. Other sources draw the boundary a week either side, which is why week 13 and week 14 can both be described as "end of the first trimester".
What appointments happen after week 12?
Next up: Quad / anomaly blood screen at 15–20 weeks, Anatomy scan at 18–22 weeks, Glucose tolerance test at 24–28 weeks. The full schedule is in the table above; exact timing varies by country and by your care team.