Pregnancy tracker

Everything on this page runs off one convention used everywhere in US obstetrics: a pregnancy is dated 280 days (40 weeks) from the first day of the last menstrual period, per ACOG's due-date methodology. If you enter a due date, the tracker counts back 280 days to that anchor; if you enter a last period, it counts forward. Your week-plus-day, trimester, progress bar, and every appointment window are all computed from that single anchor, so they always agree with each other — and with what your provider's wheel or app says, as long as you both use the same due date.

ACOG retired the idea of one 'term' at 37 weeks because outcomes keep improving up to 39 weeks. The official definitions: early term is 37 weeks 0 days through 38 weeks 6 days; full term is 39 weeks 0 days through 40 weeks 6 days; late term is 41 weeks 0 days through 41 weeks 6 days; and postterm is 42 weeks and beyond. That's why elective deliveries aren't scheduled before 39 weeks without a medical reason, and why this tracker counts down to 39 weeks 0 days — the start of the window where babies do best.

For an uncomplicated pregnancy, the standard US rhythm is: a first visit around 8 weeks (often 6–10), then a visit every 4 weeks until 28 weeks, every 2 weeks from 28 to 36 weeks, and every week from 36 weeks until birth. Each visit typically checks blood pressure, weight, urine, the baby's heartbeat, and — later on — fundal height and position. Twins, chronic conditions, or complications mean more visits, and some practices now offer fewer, longer visits or telehealth for low-risk pregnancies. Your provider's schedule wins over any calculator, including this one.

The big fixed windows: first-visit labs (blood type, blood count, urine, and screening for HIV, syphilis, and hepatitis B — all recommended for every pregnancy); cell-free DNA screening any time from 10 weeks and the nuchal-translucency scan by about 13 weeks, if you choose screening; the anatomy ultrasound at 18–22 weeks; the glucose screen for gestational diabetes at 24–28 weeks; the Tdap vaccine at 27–36 weeks; and the group B strep swab at 36–37 weeks. Everyone is re-screened for syphilis early in the third trimester (~28 weeks) per ACOG's 2024 guidance; HIV retesting is added based on risk and local prevalence. The tracker turns each window into real calendar dates for your pregnancy.

Not unless you ask. By default the tracker computes everything in your browser and keeps nothing — close the tab and it's gone. If you tick 'remember my due date on this device,' exactly one thing is stored in this browser's local storage: the due date. No name, no cycle data, no history, and nothing is ever sent to us or anyone else. The 'Forget my due date' button deletes it instantly. We treat reproductive data as sensitive by default — on a shared or family device, consider leaving the remember box unticked.

Update the tracker with the new date — the ultrasound wins. ACOG's guidance is that a first-trimester dating scan is the most accurate way to date a pregnancy, and providers formally redate when the scan disagrees with period-based dates by more than a set threshold (for example, more than 5 days in the first trimester). Once an early scan sets the due date of record, later scans don't usually change it. Every week number, milestone, and test window on this page shifts with the due date you enter, so keeping it current keeps the whole dashboard honest.