IUI Due Date Calculator

Q: Does an hCG ovulation trigger change the result?

No. The trigger times ovulation (about 24–36 hours later); using the IUI date still gives the correct estimated EDD.

Q: I had two IUIs on back-to-back days. Which date should I use?

Use the first IUI or the likely ovulation day; either choice is usually within a day. Early ultrasound can refine the date.

Q: Do twins change the due date?

The calculated EDD is the same, but multiple pregnancies often deliver earlier than singleton pregnancies.

Q: Which method is most accurate?

First-trimester ultrasound is typically the most accurate method for pregnancy dating.

Enter your IUI date to get an estimated due date (EDD) and gestational age today. We assume conception occurred on/near the IUI and add 38 weeks. If you had an hCG ‘trigger,’ timing is already baked in—gestational age is counted from a clinical LMP two weeks before the IUI.

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Methodology & Limits

What this estimates
Obstetric dating counts gestational age from the last menstrual period (LMP). For IUI, this tool sets a “clinical LMP” as the IUI date minus 14 days and returns an estimated due date (EDD) as IUI + 266 days (identical to LMP + 280). See ACOG’s guidance on due date calculation for background. ACOG Committee Opinion No. 700.

Trigger timing and IUI scheduling
A trigger (hCG) is commonly given to time ovulation; many programs schedule IUI around 24–36 hours after the trigger. This timing improves coordination but does not change the due date formula above. Example data comparing 24 vs 36 hours after hCG are published in Fertility and Sterility. Fertil Steril study on IUI timing after hCG.

Gestational age today
The calculator reports gestational age as the days elapsed since the clinical LMP (IUI minus 14 days). This mirrors the standard obstetric convention endorsed by ACOG. ACOG CO 700.

Timeline hints (typical)
Home urine test: most reliable on or after the first missed period; with IUI-based dating that is about 14 days after IUI. NHS: when to take a pregnancy test.
Serum beta hCG: many clinics check around 12–14 days after IUI. Example protocols: USF IUI patient handbook.
Early heartbeat scan: often visible by ~6 weeks gestational age with high-quality transvaginal ultrasound. Radiopaedia: fetal heart beat.
NIPT: commonly offered at 10 weeks and beyond. ACOG prenatal genetic testing chart.
Anatomy scan: standard second-trimester ultrasound is usually at 18–22 weeks. ACOG: ultrasound exams.
Third trimester: begins at 28 weeks in many clinical guides. NHS: week 28.

Multiples note
The tool always displays a single EDD, but twins and higher-order pregnancies are typically delivered earlier than 40 weeks. Guidance for uncomplicated twins often targets 37–38 weeks (chorionicity specific), with earlier timing for special cases. See professional guidance summaries and reviews. AJOG MFM: delivery timing in twins · ACOG Practice Bulletin on multifetal gestations.

Limitations and safety
Dates are population-based estimates and may be adjusted by your clinician using early ultrasound. If you have heavy bleeding, severe pain, fainting, fever, or any urgent concerns, seek care immediately. This tool is educational and not medical advice.

What’s next?

Tip: First-trimester ultrasound usually gives the most precise dating.

Frequently asked questions

How is my IUI due date calculated?

We treat the IUI date as the approximate day of fertilization and add 38 weeks (266 days) to get the EDD. Gestational age (GA) is measured from a “clinical LMP,” which is two weeks before the IUI. So GA today ≈ (days since IUI) + 14 days.

Does an hCG ovulation trigger change the result?

Not for the calculator math. The trigger simply times ovulation (typically 24–36 hours later) so your insemination matches release. Using the IUI date still yields the correct estimated EDD.

I had two IUIs on back-to-back days. Which date should I use?

Use the first IUI or your likely ovulation day; either choice is usually within a day. Your first-trimester ultrasound can refine dating.

Do twins change the due date?

The calculated EDD is the same, but actual delivery with multiples is often earlier. Follow your clinician’s plan for monitoring and timing.

Which method is most accurate?

Early ultrasound (usually in the first trimester) provides the most precise dating. LMP- or IUI-based dates are estimates.

Sources

ACOG: Methods for Estimating the Due Date — Naegele’s rule; ultrasound dating.
Cleveland Clinic: Intrauterine Insemination (IUI) — timing around LH surge/hCG trigger.
March of Dimes: Multiples — typical course of multiple pregnancies.

Educational use only. For personal medical guidance or dating changes based on ultrasound, follow your clinician’s advice.