18 Weeks Pregnant — Baby Is the Size of a Bell pepper
At 18 weeks you are 126 days into the 40-week count, with 154 days to go and 45% of the pregnancy behind you. Baby is about the size of a bell pepper and weighs about 5.7 g. This page fixes week 18 in place: what is developing, which appointments are still ahead, and how the week maps onto months.
45% 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
You might feel the first flutter of movement now. Ears begin to pick up the sound of your voice.
Measured in months, week 18 sits in month 5: Halfway: the anatomy scan happens now, and the first flutters usually become unmistakable kicks.
Appointments still ahead
| Window | Appointment | What it checks |
|---|---|---|
| 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 18
| Week | Size | Weight |
|---|---|---|
| 17 | a turnip | about 4.5 g |
| 18 | a bell pepper | about 5.7 g |
| 19 | a mango | about 7 g |
Frequently asked
What does 18 weeks pregnant mean in days and months?
18 weeks is 126 days since the first day of your last period, which is about 5 months pregnant on the four-week-per-month convention. 154 days remain in the 40-week count from here — that is 45% of the way through.
How big is a baby at 18 weeks?
Around the size of a bell pepper, at about 5.7 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 18?
The 2nd 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 18?
Next up: Glucose tolerance test at 24–28 weeks, Routine growth checks at 28–34 weeks, Group B strep swab at 34–36 weeks. The full schedule is in the table above; exact timing varies by country and by your care team.