Egg Retrieval Date (Fresh IVF)
Embryo Transfer Date (FET)
— Select Embryo Age —
Day 3 (Cleavage Stage)
Day 5 (Blastocyst)
Day 6 (Blastocyst)
Calculation Results:
function showHideInputs() {
var datingMethod = document.getElementById("datingMethod").value;
if (datingMethod === "eggRetrieval") {
document.getElementById("eggRetrievalInputs").style.display = "block";
document.getElementById("embryoTransferInputs").style.display = "none";
} else {
document.getElementById("eggRetrievalInputs").style.display = "none";
document.getElementById("embryoTransferInputs").style.display = "block";
}
}
function calculateIVFWeeks() {
var datingMethod = document.getElementById("datingMethod").value;
var today = new Date();
today.setHours(0, 0, 0, 0); // Normalize today's date to start of day
var equivalentLMP;
var inputDate;
var embryoAge;
if (datingMethod === "eggRetrieval") {
var eggRetrievalDateStr = document.getElementById("eggRetrievalDate").value;
if (!eggRetrievalDateStr) {
document.getElementById("ivfResult").innerHTML = "Please enter the Date of Egg Retrieval.";
return;
}
inputDate = new Date(eggRetrievalDateStr);
inputDate.setHours(0, 0, 0, 0);
if (inputDate > today) {
document.getElementById("ivfResult").innerHTML = "Egg Retrieval Date cannot be in the future.";
return;
}
// For fresh IVF, pregnancy is dated from 2 weeks before egg retrieval (equivalent to LMP)
equivalentLMP = new Date(inputDate);
equivalentLMP.setDate(equivalentLMP.getDate() – 14);
} else { // embryoTransfer
var embryoTransferDateStr = document.getElementById("embryoTransferDate").value;
embryoAge = parseInt(document.getElementById("embryoAge").value);
if (!embryoTransferDateStr) {
document.getElementById("ivfResult").innerHTML = "Please enter the Date of Embryo Transfer.";
return;
}
if (isNaN(embryoAge)) {
document.getElementById("ivfResult").innerHTML = "Please select the Embryo Age at Transfer.";
return;
}
inputDate = new Date(embryoTransferDateStr);
inputDate.setHours(0, 0, 0, 0);
if (inputDate > today) {
document.getElementById("ivfResult").innerHTML = "Embryo Transfer Date cannot be in the future.";
return;
}
// For FET, calculate equivalent LMP: Transfer Date – Embryo Age – 14 days
equivalentLMP = new Date(inputDate);
equivalentLMP.setDate(equivalentLMP.getDate() – embryoAge – 14);
}
// Calculate Estimated Due Date (EDD)
// EDD is 280 days (40 weeks) from equivalent LMP
var eddDate = new Date(equivalentLMP);
eddDate.setDate(eddDate.getDate() + 280);
// Calculate current gestational age
var diffTimeTodayLMP = today.getTime() – equivalentLMP.getTime();
var daysSinceLMP = Math.floor(diffTimeTodayLMP / (1000 * 60 * 60 * 24));
if (daysSinceLMP < 0) {
document.getElementById("ivfResult").innerHTML = "The selected date is in the future. Please select a past or current date.";
return;
}
var currentWeeks = Math.floor(daysSinceLMP / 7);
var currentDays = daysSinceLMP % 7;
// Calculate days remaining to EDD
var diffTimeEDDToday = eddDate.getTime() – today.getTime();
var daysToEDD = Math.ceil(diffTimeEDDToday / (1000 * 60 * 60 * 24));
if (daysToEDD = 0 && currentWeeks = 14 && currentWeeks = 28) {
trimester = "Third Trimester";
} else {
trimester = "Not yet pregnant or invalid date range";
}
// Format dates for display
var options = { year: 'numeric', month: 'long', day: 'numeric' };
var eddFormatted = eddDate.toLocaleDateString('en-US', options);
// Display results
document.getElementById("eddResult").innerHTML = "Estimated Due Date (EDD): " + eddFormatted;
document.getElementById("gestationalAgeResult").innerHTML = "Current Gestational Age: " + currentWeeks + " weeks and " + currentDays + " days";
document.getElementById("trimesterResult").innerHTML = "Current Trimester: " + trimester;
document.getElementById("daysToEDDResult").innerHTML = "Days Remaining to EDD: " + daysToEDD + " days";
}
// Initialize display on load
window.onload = showHideInputs;
Understanding IVF Pregnancy Dating
Dating a pregnancy conceived through In Vitro Fertilization (IVF) is often more precise than dating a naturally conceived pregnancy. This is because with IVF, the exact dates of egg retrieval, fertilization, and embryo transfer are known. This calculator helps you determine your estimated due date (EDD), current gestational age, and trimester based on these specific IVF milestones.
How IVF Dating Differs
In a natural pregnancy, the due date is typically calculated from the first day of the Last Menstrual Period (LMP), assuming ovulation occurs around day 14 of a 28-day cycle. This makes the pregnancy approximately 40 weeks long from LMP, or 38 weeks from conception/ovulation.
With IVF, we bypass the uncertainty of ovulation and conception timing. Instead, we use the known dates:
For Fresh IVF Cycles: The date of egg retrieval is considered equivalent to the date of ovulation. Therefore, pregnancy is dated from two weeks prior to the egg retrieval date, mimicking the LMP method.
For Frozen Embryo Transfer (FET) Cycles: The embryo's age at transfer (e.g., Day 3 or Day 5 blastocyst) is crucial. We work backward from the transfer date, accounting for the embryo's age and the standard two weeks prior to ovulation, to establish an "equivalent LMP."
Using the IVF Pregnancy Week by Week Calculator
Our calculator offers two methods to accurately date your IVF pregnancy:
Egg Retrieval Date (Fresh IVF):
If you underwent a fresh IVF cycle, simply select "Egg Retrieval Date" from the dropdown and enter the exact date your eggs were retrieved. The calculator will then determine your EDD and current gestational age based on this date.
Example: If your egg retrieval was on January 15, 2024, the calculator will treat January 1, 2024, as your equivalent LMP to calculate your due date and current weeks.
Embryo Transfer Date (FET):
For frozen embryo transfers, choose "Embryo Transfer Date" and provide two pieces of information:
Date of Embryo Transfer: The exact date your embryo(s) were transferred.
Embryo Age at Transfer: Whether it was a Day 3 (cleavage stage) or Day 5/6 (blastocyst) embryo. This is vital as it tells us how many days old the embryo was at the time of transfer.
Example: If a Day 5 blastocyst was transferred on January 20, 2024, the calculator will determine your equivalent fertilization date as January 15, 2024 (Jan 20 – 5 days). Your equivalent LMP would then be January 1, 2024 (Jan 15 – 14 days), from which your due date and gestational age are calculated.
Understanding Your Results
Estimated Due Date (EDD): This is the projected date your baby is expected to arrive, typically 40 weeks from your equivalent LMP.
Current Gestational Age: This tells you how many weeks and days pregnant you are as of today's date, based on your IVF procedure.
Current Trimester: Pregnancy is divided into three trimesters:
First Trimester: Weeks 1-13
Second Trimester: Weeks 14-27
Third Trimester: Weeks 28 until birth
Days Remaining to EDD: The number of days left until your estimated due date.
While IVF dating is highly accurate, remember that your EDD is still an estimate. Only about 5% of babies are born on their exact due date. Your healthcare provider will use these dates, along with ultrasound measurements, to monitor your pregnancy progress. Always consult with your doctor for personalized medical advice.