Frequently Asked Questions

Standard pregnancy calculators estimate due dates using Naegele's Rule. This rule adds 280 days (40 weeks) to the first day of your Last Menstrual Period (LMP). In this calculator, we automatically adjust for cycle length: if your cycle is longer or shorter than the typical 28 days, the formula adds or subtracts the difference to give you a more accurate due date.

Gestational Age measures the pregnancy from the first day of your LMP, which is roughly 2 weeks before conception actually occurs. This is the timeline doctors and midwives use.

Fetal Age (or conception age) is the actual age of the developing fetus starting from the day of fertilization. It is typically 2 weeks shorter than gestational age.

An Estimated Due Date is only an estimate—only about 4% of babies are born on their exact due date. Most babies are delivered within two weeks before or after their EDD.

The most accurate date is typically determined via a first-trimester ultrasound scan, which measures the embryo's physical length (crown-rump length).

For In Vitro Fertilization (IVF) pregnancies, the date of conception is known precisely because the embryo is fertilized in a lab.

• Day 3 embryo transfer: due date = transfer date + 263 days
• Day 5 embryo transfer (blastocyst): due date = transfer date + 261 days

You should take a pregnancy test on or after the first day of your missed period. For the most accurate result, wait at least one week after a missed period. Testing too early can produce a false negative because hCG (the pregnancy hormone) may not yet be at detectable levels.

If your cycles are irregular, count at least 21 days after your last unprotected intercourse before testing.

Most home pregnancy tests can detect hCG as early as 10 days after conception, which is typically about 4 days before your expected period. However, the accuracy improves significantly if you wait until the first day of your missed period or later.

For the earliest possible detection, use a first-morning urine sample, which contains the highest concentration of hCG.

To calculate how many weeks pregnant you are, count the number of full weeks since the first day of your last menstrual period (LMP). This is how obstetricians determine gestational age.

For example, if your LMP was 6 weeks ago, you are 6 weeks pregnant. Our pregnancy calculator can determine your exact gestational age in weeks and days based on your LMP, conception date, or ultrasound date.

How far along you are is determined by your gestational age, measured in weeks from the first day of your last menstrual period (LMP). A full-term pregnancy is approximately 40 weeks, divided into three trimesters:

• First trimester: weeks 1–12
• Second trimester: weeks 13–26
• Third trimester: weeks 27–40

Use our calculator to enter your LMP or due date to find out exactly how far along you are and which trimester you are currently in.

Some sensitive tests can detect pregnancy up to 5–6 days before your missed period, but testing after a missed period is more reliable. The earliest a test can work depends on when implantation occurs and how quickly hCG levels rise.

Most urine pregnancy tests can confirm pregnancy about 10–14 days after conception or after a missed period. Blood tests may detect pregnancy even earlier.

A pregnancy test may become positive 10–14 days after conception, depending on when implantation occurs and hCG levels rise. Testing too early may result in a false negative.

Possibly. If enough hCG has been produced after implantation, the test may be positive, but testing a few days later is more accurate. Implantation bleeding typically occurs 6–12 days after conception.

Most pregnancies can be confirmed with a urine test within 14 days after conception or after a missed period. Blood tests may detect pregnancy even earlier.

The best time is the first morning after a missed period, when urine hCG levels are highest. This provides the most reliable result and minimizes the chance of a false negative.

A chemical pregnancy is a very early miscarriage that occurs before the fifth week of pregnancy, usually shortly after implantation. It is called a "chemical" pregnancy because it can only be detected by chemical (blood or urine) tests—it is too early to be seen on an ultrasound.

Chemical pregnancies are common and do not usually indicate fertility problems. If you experience one, speak with your healthcare provider for guidance.

A full-term pregnancy typically lasts about 40 weeks, counted from the first day of your last menstrual period (LMP). This is approximately 9 months and 1 week, or 280 days.

Early pregnancy symptoms may begin 1–2 weeks after conception, though timing varies from person to person. Common early symptoms include breast tenderness, fatigue, nausea, and frequent urination.

Yes. Although uncommon, pregnancy is possible if pre-ejaculate contains sperm or picks up sperm remaining in the urethra. If you are not trying to conceive, consider using reliable contraception.

Ectopic pregnancy pain usually begins between 6 and 8 weeks of pregnancy and requires immediate medical attention. Symptoms may include sharp abdominal pain, vaginal bleeding, dizziness, and shoulder tip pain.

If you experience sudden severe abdominal pain, seek emergency medical care immediately.

Pregnancy nausea, often called morning sickness, usually starts around weeks 5–6 of pregnancy. Despite the name, it can occur at any time of day. For most women, it improves by the second trimester.

Implantation spotting typically lasts a few hours to two days. Longer or heavier bleeding should be evaluated by a healthcare provider, as it may indicate something that needs attention.

Diarrhea is not a common early pregnancy symptom, but hormonal changes can affect digestion. Persistent diarrhea should be discussed with a healthcare provider to rule out other causes.