So you’re pregnant after IVF, and now every app on your phone disagrees about how far along you are. Here’s the one rule that fixes all of it: obstetric weeks already include the embryo’s age at transfer. On a Day 5 transfer, transfer day is roughly 2 weeks and 5 days. You’re not “behind.” The apps are just confused.
Once you translate the clocks, an IVF pregnancy follows the same week-by-week path as any other. Here’s that path, with the IVF-specific notes that actually matter.
The dating math (memorize this once)
Transfer date + 266 days − embryo age = due date. Day 5 transfer = 261 days. Day 7 = 259. Write three things in ink on a paper calendar: your transfer date, your embryo day, and the due date. Then write “GA on transfer day” (for Day 5: 2 weeks, 5 days). Every Sunday, add one week. You now need zero apps.
Our IVF due date calculator does this math for you, and the IVF due date vs ultrasound due date guide explains what happens when the first scan disagrees.
Weeks 4–6: beta territory
Blood tests, then a first ultrasound to confirm the pregnancy is in the uterus and check for a heartbeat. Progesterone symptoms (bloating, fatigue, sore everything) dominate. Do not grade the pregnancy by how nauseous you feel — plenty of healthy pregnancies have zero nausea.
Weeks 7–12: heartbeat to first-trimester screening
Heartbeat confirmed, medications taper per your clinic’s protocol. This is when NIPT or NT screening conversations happen. One IVF-specific note: tell your OB the whole pipeline — whose eggs, whether donor, whether PGT was done — so they don’t order redundant or misleading tests.
Weeks 13–27: anatomy scan and the middle stretch
Anatomy scan, glucose testing, first movements. This is when many people announce. IVF doesn’t skip any of these visits or change their timing.
Weeks 28 to birth: the home stretch
Blood pressure monitoring, growth scans if indicated, birth timing discussions. Going past your due date is allowed in uncomplicated singletons with surveillance. Twins follow a different playbook — earlier delivery is standard.
Patient questions, answered honestly
“My app says I’m 5 weeks but my clinic says 7. Which is right?”
Your clinic. The app is counting from a last period you didn’t have. Delete it or fix the dates.
“The ultrasound measured a few days off from my transfer date. Should I worry?”
A few days of difference is common and usually not a reason to change the IVF date. Clinics typically keep the transfer-based date unless the scan disagrees by a larger margin. Ask your team what their threshold is.
“Do I need extra monitoring because it’s IVF?”
Not automatically. An uncomplicated IVF singleton follows standard obstetric care. Your OB might do one extra early scan for dating confirmation, and that’s usually it.
“When can I stop the progesterone?”
Only when your clinic tells you to. The taper schedule varies — don’t adjust it based on internet forums.
Fruit sizes and other nonsense
Those fruit-size illustrations are memory aids, not measurements. In the first days after transfer, no website can honestly give you a size comparison — you’re not carrying a grape yet even though the obstetric week number already started. Anyone who tells you otherwise is guessing.
What week-by-week emails should never do
They should not diagnose reduced movement. They should not tell you to stop blood thinners. They should not sell unproven immune treatments. If a newsletter contradicts your obstetrician, the obstetrician wins — every time.
Sources
- ACOG: How Your Fetus Grows During Pregnancy
- NHS: Pregnancy week by week
- HFEA: In vitro fertilisation (IVF)
Screenshot your transfer date, embryo day, and due date calculation and keep it with your lab report. If a new office ever overwrites your chart with LMP math, you’ll have the receipts.
Educational guide only — not medical advice. If your clinic chart disagrees with a date here, use the clinic chart. For pain, heavy bleeding, or fever, call your clinic’s after-hours line.