Enter your IUI date to calculate the estimated due date (EDD) assuming the procedure is successful. This tool projects dates based on clinical averages by adding 38 weeks to the date of insemination.
What’s next?
Tip: First-trimester ultrasound usually gives the most precise dating.
What to Expect After IUI
The "Two Week Wait" after intrauterine insemination can be confusing because the procedure itself—and the medications used—can mimic pregnancy symptoms.
Common Symptoms (Normal)
- Light Spotting: It is common to see a small amount of spotting immediately after the procedure. This is usually caused by the catheter irritating the cervix, not necessarily implantation.
- Cramping: Mild cramping for 24–48 hours after IUI is normal. It is caused by the passage of the catheter and the saline/sperm fluid entering the uterus.
- Bloating & Sore Breasts (Progesterone): If you are taking progesterone suppositories or had a trigger shot, you will likely feel pregnant (bloated, sore breasts, fatigue) even if you are not. These are side effects of the progesterone, not definitive signs of success.
The "Trigger Shot" False Positive
If you used an hCG trigger shot (like Ovidrel, Novarel, or Pregnyl), remember that this medication is the pregnancy hormone. If you test too early (e.g., 7 days after IUI), the test will pick up the medication and give you a False Positive. Most clinics recommend waiting at least 14 days post-IUI to ensure the trigger has left your system.
Frequently asked questions
How is my IUI due date calculated?
We treat the IUI date as the day fertilisation likely happened (Conception) and add 38 weeks (266 days) to estimate the due date. Gestational age is counted from an assumed last menstrual period two weeks before the IUI.
Does an hCG trigger shot change my Due Date?
No. The trigger shot simply times ovulation (typically 24–36 hours later) so the insemination matches the egg release. Using the IUI date is still the most accurate way to calculate your EDD.
Will the trigger shot affect my pregnancy test?
Yes. The trigger shot contains hCG, the same hormone pregnancy tests look for. It can cause a "False Positive" result for 10–14 days after the injection. You should wait until your clinic's recommended test date (usually 14 days post-IUI) to trust the result.
I had two IUIs on back-to-back days. Which date should I use?
Use the first IUI date. The sperm from the first procedure can survive for several days waiting for the egg. The difference in due date is negligible (only 24 hours).
Do twins change the due date?
The calculated 40-week date is the same, but the actual delivery day for multiples is almost always earlier. Twins are typically induced or delivered around 36–38 weeks depending on the type of twins.
Which dating method is most accurate?
While this calculator provides a clinical standard estimate, a first-trimester ultrasound (dating scan) is the gold standard. If your baby measures significantly differently than the IUI dates, your doctor will determine the official due date.
Methodology and limits
What this estimates
In simple terms, the calculator pretends your period started 14 days before the IUI and counts pregnancy length from there. Obstetric dating counts gestational age from the last menstrual period (LMP). For intrauterine insemination (IUI), this tool sets a clinical LMP as the IUI date minus 14 days, then returns an estimated due date (EDD) as IUI plus 266 days (the same as LMP plus 280). This follows the approach in the American College of Obstetricians and Gynecologists Committee Opinion on due date calculation (ACOG Committee Opinion No. 700).
Trigger timing and IUI scheduling
Many IUI cycles use an hCG trigger to time ovulation, with insemination planned about 24 to 36 hours later. This coordination improves the chance that sperm are present near ovulation, but it does not change the dating formula above. An example comparison of 24 versus 36 hours after hCG is reported in
Fertility and Sterility.
Gestational age today
Gestational age is reported as the time elapsed since the clinical LMP, which is set as IUI minus 14 days. This mirrors the standard obstetric convention described in
ACOG’s due date guidance.
Timeline hints (typical)
These are common time points in many IUI programs and pregnancy care pathways:
- Home urine test: often most reliable on or after the first missed period, which is about 14 days after IUI when using this dating method. See, for example, Mayo Clinic information on home pregnancy tests.
- Serum beta hCG: many clinics schedule a blood test about 12 to 14 days after IUI. An example protocol is described in the University of South Florida IUI patient handbook (PDF).
- Early heartbeat scan: with high quality transvaginal ultrasound, a fetal heartbeat is often seen by about 6 weeks gestational age. See the Radiopaedia article on fetal heart beat.
- NIPT: non-invasive prenatal testing is commonly offered from 10 weeks gestational age onwards, as summarised in the ACOG prenatal genetic testing chart.
- Anatomy scan: many services schedule a detailed second-trimester ultrasound at 18 to 22 weeks, in line with ACOG guidance on ultrasound exams.
- Third trimester: many clinical guides define the start of the third trimester at 28 weeks of gestation, as illustrated in the NHS week-28 pregnancy guide.
Multiples note
The calculator always displays a single EDD. In practice, twins and higher-order pregnancies are often delivered before 40 weeks. Reviews and professional guidance suggest planned delivery for uncomplicated twins around 37 to 38 weeks, with earlier timing for some complications. Examples include an
AJOG MFM review on delivery timing in twins and the
ACOG Practice Bulletin on multifetal gestations.
Limitations and safety
These dates are based on population averages. Individual care teams may adjust dating with early ultrasound or other findings. This tool does not replace medical assessment. If you have heavy bleeding, severe pain, fainting, fever, or any urgent concern, seek medical care immediately.