Question 1

How many weeks pregnant am I based on my last period?

Accepted Answer

Your pregnancy week is calculated from the first day of your last menstrual period (LMP), not from conception. If your last period started 56 days ago, you are 8 weeks pregnant. This is the standard method used by all healthcare providers. Conception typically occurs around week 2, so "8 weeks pregnant" means roughly 6 weeks since the embryo was conceived.

Question 2

What should I expect at each week of pregnancy?

Accepted Answer

Each week brings different developments. In weeks 5-8, the heart begins beating and major organs start forming. By weeks 9-12, all organs are formed and fingerprints develop. Weeks 13-16 bring facial expressions and gender visibility. First movements are felt around weeks 17-20. By weeks 25-28, the baby can open eyes and respond to sound. Weeks 33-36 see lung maturation, and weeks 37-40 mark full term.

Question 3

What is the difference between gestational age and fetal age?

Accepted Answer

Gestational age is measured from the first day of your last menstrual period (LMP) and is the standard used by healthcare providers. Fetal age (also called embryonic age) is measured from the date of conception, which is approximately 2 weeks after the LMP. So when your doctor says you are "10 weeks pregnant," the fetus is actually about 8 weeks old. This calculator uses gestational age, as is standard practice.

Question 4

Is it normal to be past 40 weeks pregnant?

Accepted Answer

Yes, going past 40 weeks is common, especially for first-time mothers. About 50% of first pregnancies extend beyond 40 weeks. A full-term pregnancy is defined as 37-42 weeks. Your healthcare provider will typically discuss induction options if you reach 41-42 weeks. Only about 5% of babies are born on their exact due date — most arrive within a 2-week window before or after.

Question 5

When does each trimester start and end?

Accepted Answer

The first trimester spans weeks 1-12 (months 1-3) — this is when organs form and morning sickness is most common. The second trimester covers weeks 13-26 (months 4-6) — often called the "honeymoon phase" because many symptoms ease and you feel the first kicks. The third trimester runs from week 27 to delivery (months 7-9) — the baby gains most of its weight and prepares for birth.

Question 6

How accurate is pregnancy week tracking from LMP?

Accepted Answer

LMP-based pregnancy dating is accurate to within 1-2 weeks for women with regular 28-day cycles. For irregular cycles, accuracy decreases. An early ultrasound (before 12 weeks) can narrow the estimate to within 5-7 days. Later ultrasounds are less reliable for dating. If your ultrasound dating differs from your LMP date by more than a week in the first trimester, your provider may adjust your estimated due date.

Question 7

When should I schedule my first prenatal appointment?

Accepted Answer

Most healthcare providers recommend scheduling your first prenatal visit between weeks 6-8 (2-4 weeks after a missed period). This visit typically includes a dating ultrasound, blood work, medical history review, and confirmation of pregnancy viability. If you have a history of complications, are over 35, or experience bleeding or severe pain, contact your provider as soon as you get a positive test.

Pregnancy Week Calculator — How Many Weeks Pregnant Am I?