Pregnancy Timeline Calculator

Pregnancy Timeline Calculator

Your Pregnancy Timeline

Estimated Due Date (EDD):

Approximate Conception Date:

Current Gestational Age:

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Trimester Breakdown:

• First Trimester:
• Second Trimester:
• Third Trimester:

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Key Milestones:

• First Fetal Heartbeat (approx. 6-8 weeks):
• Gender Reveal Ultrasound (approx. 18-22 weeks):
• Viability (approx. 24 weeks):

function calculatePregnancyTimeline() { var lmpDateInput = document.getElementById("lmpDate").value; var resultDiv = document.getElementById("timelineResult"); if (!lmpDateInput) { alert("Please enter your Last Menstrual Period (LMP) start date."); resultDiv.style.display = "none"; return; } var lmp = new Date(lmpDateInput); if (isNaN(lmp.getTime())) { alert("Invalid date entered. Please use a valid date format."); resultDiv.style.display = "none"; return; } var today = new Date(); today.setHours(0, 0, 0, 0); // Normalize today's date to start of day // Ensure LMP is not in the future if (lmp > today) { alert("LMP date cannot be in the future. Please enter a past or current date."); resultDiv.style.display = "none"; return; } // — Calculations — // Estimated Due Date (EDD): LMP + 280 days (40 weeks) var edd = new Date(lmp.getTime()); edd.setDate(lmp.getDate() + 280); // Approximate Conception Date: LMP + 14 days (2 weeks) var conceptionDate = new Date(lmp.getTime()); conceptionDate.setDate(lmp.getDate() + 14); // Current Gestational Age var timeDiff = today.getTime() – lmp.getTime(); var daysDiff = Math.floor(timeDiff / (1000 * 60 * 60 * 24)); var currentWeeks = Math.floor(daysDiff / 7); var currentDays = daysDiff % 7; // Trimester Dates var firstTrimesterEnd = new Date(lmp.getTime()); firstTrimesterEnd.setDate(lmp.getDate() + (13 * 7) + 6); // End of 13 weeks, 6 days var secondTrimesterStart = new Date(lmp.getTime()); secondTrimesterStart.setDate(lmp.getDate() + (14 * 7)); // Start of 14 weeks var secondTrimesterEnd = new Date(lmp.getTime()); secondTrimesterEnd.setDate(lmp.getDate() + (27 * 7) + 6); // End of 27 weeks, 6 days var thirdTrimesterStart = new Date(lmp.getTime()); thirdTrimesterStart.setDate(lmp.getDate() + (28 * 7)); // Start of 28 weeks var thirdTrimesterEnd = new Date(edd.getTime()); // Same as EDD // Key Milestones var heartbeatDate = new Date(lmp.getTime()); heartbeatDate.setDate(lmp.getDate() + (7 * 6)); // Approx 6 weeks var genderRevealDate = new Date(lmp.getTime()); genderRevealDate.setDate(lmp.getDate() + (7 * 18)); // Approx 18 weeks var viabilityDate = new Date(lmp.getTime()); viabilityDate.setDate(lmp.getDate() + (7 * 24)); // Approx 24 weeks // — Display Results — var options = { year: 'numeric', month: 'long', day: 'numeric' }; document.getElementById("eddResult").innerText = edd.toLocaleDateString('en-US', options); document.getElementById("conceptionResult").innerText = conceptionDate.toLocaleDateString('en-US', options); document.getElementById("gestationalAgeResult").innerText = currentWeeks + " weeks and " + currentDays + " days"; document.getElementById("firstTrimesterResult").innerText = lmp.toLocaleDateString('en-US', options) + " to " + firstTrimesterEnd.toLocaleDateString('en-US', options); document.getElementById("secondTrimesterResult").innerText = secondTrimesterStart.toLocaleDateString('en-US', options) + " to " + secondTrimesterEnd.toLocaleDateString('en-US', options); document.getElementById("thirdTrimesterResult").innerText = thirdTrimesterStart.toLocaleDateString('en-US', options) + " to " + thirdTrimesterEnd.toLocaleDateString('en-US', options); document.getElementById("heartbeatResult").innerText = heartbeatDate.toLocaleDateString('en-US', options); document.getElementById("genderRevealResult").innerText = genderRevealDate.toLocaleDateString('en-US', options); document.getElementById("viabilityResult").innerText = viabilityDate.toLocaleDateString('en-US', options); resultDiv.style.display = "block"; }

Understanding Your Pregnancy Timeline

A pregnancy timeline calculator is a valuable tool for expectant parents, helping to estimate key dates throughout the pregnancy journey. By simply inputting the first day of your Last Menstrual Period (LMP), the calculator can provide an estimated due date, approximate conception date, current gestational age, and a breakdown of trimesters and important milestones.

How It Works: Naegele's Rule

The most common method used by healthcare providers and pregnancy calculators to estimate a due date is called Naegele's Rule. This rule assumes a 28-day menstrual cycle with ovulation occurring on day 14. It calculates the Estimated Due Date (EDD) by adding 280 days (40 weeks) to the first day of your Last Menstrual Period (LMP).

While this rule provides a good estimate, it's important to remember that it's an average. Only about 4% of babies are born exactly on their due date. Most babies arrive sometime between 37 and 42 weeks of gestation.

Key Dates Explained:

• Last Menstrual Period (LMP): This is the first day of your last period. It's considered the starting point of your pregnancy, even though conception typically occurs about two weeks later.
• Estimated Due Date (EDD): This is the date your baby is expected to arrive, calculated as 40 weeks from your LMP.
• Approximate Conception Date: This is the estimated date when fertilization likely occurred, usually around two weeks after your LMP.
• Current Gestational Age: This tells you how many weeks and days pregnant you are, based on your LMP and today's date.

Trimester Breakdown:

Pregnancy is divided into three trimesters, each marked by significant developmental changes for the baby and physical changes for the mother:

• First Trimester (Weeks 1-13): This period begins with your LMP and ends at 13 weeks and 6 days. It's a time of rapid development, with all major organs forming. Many women experience morning sickness and fatigue during this stage.
• Second Trimester (Weeks 14-27): Starting at 14 weeks and ending at 27 weeks and 6 days, this is often considered the "golden trimester." Morning sickness usually subsides, energy levels may increase, and you might start to feel the baby move.
• Third Trimester (Weeks 28-40): From 28 weeks until delivery, the baby grows rapidly, gaining weight and maturing its organs. The mother may experience more discomfort as the baby gets larger, preparing for birth.

Important Milestones:

• First Fetal Heartbeat: Often detectable by ultrasound between 6 to 8 weeks of gestation.
• Gender Reveal Ultrasound: Typically performed during the anatomy scan between 18 to 22 weeks, where the baby's sex can often be determined.
• Viability: Around 24 weeks, a baby born prematurely has a reasonable chance of survival with intensive medical care.

Disclaimer:

This calculator provides estimates based on standard medical formulas. It is not a substitute for professional medical advice. Always consult with your healthcare provider for accurate dating, personalized guidance, and any concerns regarding your pregnancy.