Question 1

How is a due date calculated?

Accepted Answer

A pregnancy due date is calculated using Naegele's Rule: add 280 days (40 weeks) to the first day of your last menstrual period (LMP). This is the standard method used by midwives and obstetricians worldwide. If you know your conception date, 266 days are added instead. Due dates are always estimates — ultrasound confirmation is more accurate, especially in the first trimester.

Question 2

How accurate is a due date calculator?

Accepted Answer

Due date calculators based on LMP are accurate to within 1–2 weeks for most people. However, individual variation in cycle length and ovulation timing can shift the actual due date. First-trimester ultrasound (8–13 weeks) is the most accurate method for confirming gestational age, with accuracy of ±5–7 days. Later ultrasounds are less accurate for dating.

Question 3

What does gestational age mean?

Accepted Answer

Gestational age is the number of weeks of pregnancy counted from the first day of your last menstrual period, not from conception. This means that at the time of conception (approximately week 2–3), you are already considered 2–3 weeks pregnant. A full-term pregnancy is 40 weeks gestational age. Doctors and midwives always use gestational age in weeks for clinical monitoring.

Question 4

What are the three trimesters of pregnancy?

Accepted Answer

Pregnancy is divided into three trimesters. The first trimester covers weeks 1–12 and involves the most critical organ development. The second trimester spans weeks 13–26 — often the most comfortable period, with the baby's movements becoming noticeable. The third trimester is weeks 27–40, when the baby gains most of its weight and prepares for birth.

Question 5

What is considered full term?

Accepted Answer

A pregnancy is considered full term from 39 weeks 0 days to 40 weeks 6 days. Early term is 37–38 weeks. Late term is 41 weeks. Post term is 42 weeks or beyond. Babies born before 37 weeks are considered preterm. The American College of Obstetricians and Gynecologists recommends avoiding elective delivery before 39 weeks when possible.

Question 6

When should I take a pregnancy test?

Accepted Answer

Home pregnancy tests detect hCG (human chorionic gonadotrophin), which first appears in urine around 10–14 days after conception. The most reliable time to test is after a missed period (approximately 14 days after ovulation). Testing earlier may give a false negative. A positive result should be followed up with confirmation from a healthcare provider and booking of a first prenatal appointment.

🤰 Pregnancy Due Date Calculator

🤰 Naegele's Rule

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