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First Trimester Checklist: What to Do in Weeks 1–13 of Pregnancy

A practical guide to the first trimester — from confirming your pregnancy and booking prenatal care to screening tests, nutrition, and safe self-care during the first 13 weeks. Educational only.

25 June 2026 4 min read By Tools.Town Team Fact Checked

Key Takeaways

  • Book as soon as your pregnancy is confirmed — ideally before 8 weeks
  • For most pregnancies, moderate exercise is safe and beneficial
  • Avoid raw or undercooked meat and fish, unpasteurised dairy, raw sprouts, high-mercury fish (shark, swordfish, marlin), excessive caffeine (limit to 200 mg/day), and alcohol
  • Yes

This checklist is for general educational purposes only. Every pregnancy is different. Always follow the personalised guidance of your obstetrician, midwife, or prenatal care provider.

Week 1–4: confirmation and first steps

Confirm your pregnancy

Home urine pregnancy tests are accurate from the first day of a missed period (approximately 2 weeks after conception). For a more sensitive test, a blood test (serum β-hCG) at a clinic can detect pregnancy 7–10 days after fertilisation.

Once confirmed, calculate your estimated due date using the Pregnancy Due Date Calculator — enter your last menstrual period date and typical cycle length. This gives you your estimated due date (EDD), likely fertilisation date, and trimester milestones.

Start prenatal vitamins (if you haven’t already)

Folic acid is the most critical supplement in early pregnancy. Neural tube defects (spina bifida, anencephaly) develop in the first 4–6 weeks, often before most women know they are pregnant. Take at least 400 mcg of folic acid daily — your provider may recommend 800 mcg or more if you have a history of neural tube defects or are on certain medications.

Prenatal vitamins also include iron, calcium, vitamin D, iodine, and DHA. Start taking them as soon as pregnancy is confirmed (or when trying to conceive).

Book your first prenatal appointment

Call your OB/GYN or midwife as soon as pregnancy is confirmed. The “booking appointment” typically happens between weeks 8 and 12 and covers:

  • Confirming gestational age and EDD
  • Blood tests (blood type, Rh factor, CBC, infectious disease screening)
  • Urine analysis
  • Blood pressure baseline
  • Medical history review
  • Discussion of prenatal screening options

Weeks 5–8: first trimester screenings and self-care

Manage morning sickness

Nausea affects up to 80% of pregnant women, typically starting around week 5–6 and peaking around week 9. Strategies that help:

  • Eat small, frequent meals (empty stomach worsens nausea)
  • Eat plain carbohydrates (crackers, toast) before getting up
  • Stay hydrated — sipping cold water or ginger tea
  • Vitamin B6 (pyridoxine) supplements have good evidence for reducing nausea
  • Avoid strong smells that trigger nausea

If vomiting prevents keeping any food or fluid down (hyperemesis gravidarum), contact your provider. IV fluids and antiemetic medication may be needed.

Understand what to avoid

The first trimester is when organ formation occurs — making it the highest-risk period for environmental exposures.

Food to avoid:

  • Raw or undercooked meat, poultry, eggs, and fish (Listeria, Salmonella, Toxoplasma risk)
  • Unpasteurised dairy products and soft cheeses
  • High-mercury fish: shark, swordfish, king mackerel, marlin, orange roughy, bigeye tuna
  • Raw sprouts (alfalfa, clover)
  • Unpasteurised juices

Limit:

  • Caffeine to 200 mg/day (about 1 small filter coffee or 2 cups of tea)
  • Avoid alcohol entirely — no safe limit has been established

Medications: Always check with your provider before taking any OTC medication, herbal supplement, or prescription drug. Ibuprofen and aspirin (unless specifically prescribed) should be avoided.

Stay active (with modifications)

Unless your provider advises otherwise, continue moderate exercise. Benefits include better sleep, reduced back pain, improved mood, and easier labour. Safe activities: brisk walking, swimming, stationary cycling, prenatal yoga.

Avoid: contact sports, high-impact exercise, activities with fall risk, hot yoga or hot tubs (core temperature elevation is a risk factor for neural tube defects).

Weeks 9–12: first-trimester screening

Nuchal translucency ultrasound (11–13+6 weeks)

This ultrasound measures fluid at the back of the baby’s neck (nuchal translucency). An increased measurement is associated with a higher risk of chromosomal abnormalities (Down syndrome, trisomy 18). The result is combined with blood tests (PAPP-A, free β-hCG) to produce a first-trimester combined screening risk score.

Non-invasive prenatal testing (NIPT) / Cell-free DNA

NIPT is a blood test available from 10 weeks that analyses fragments of fetal DNA in the maternal bloodstream. It screens for:

  • Trisomy 21 (Down syndrome) — >99% detection rate
  • Trisomy 18 (Edwards syndrome)
  • Trisomy 13 (Patau syndrome)
  • Sex chromosome abnormalities
  • Optionally: fetal sex

NIPT is a screening test, not diagnostic — a positive result requires diagnostic confirmation (CVS or amniocentesis). Discuss whether NIPT is appropriate for you with your provider.

Chorionic villus sampling (CVS) — 10–13 weeks

CVS is a diagnostic test (not a screening test) that takes a small sample of placental cells for chromosomal analysis. It carries a 0.5–1% procedure-related miscarriage risk. It is offered when screening suggests elevated risk, or when the family history makes chromosomal conditions likely.

Weeks 12–13: end of the first trimester

The 12-week milestone

After 12 weeks, all major organ systems are formed (though not fully functional). The risk of miscarriage drops significantly. Many couples choose to share their news at this point.

Checklist for end of first trimester

  • EDD confirmed by provider (ultrasound or LMP date)
  • Blood type and Rh factor known
  • First-trimester combined screening or NIPT completed
  • Prenatal vitamins (including 400 mcg+ folic acid) taken daily
  • Dental check-up scheduled (pregnancy increases gum disease risk)
  • Workplace disclosure plan considered (physically demanding jobs may need modification)
  • Health insurance and maternity leave options reviewed
  • Birth preferences research started (hospital vs. birthing centre vs. home birth)
  • Registered for antenatal/prenatal classes (many start from week 20–28)

Nutrition in the first trimester

Many women find appetite reduced by nausea in the first trimester. Calorie needs are not significantly higher in the first trimester (an extra 100–150 kcal/day is often cited, but listen to your body). Focus on quality over quantity:

  • Protein: Eggs, legumes, dairy, lean meat — support fetal cell growth
  • Iron: Lean red meat, spinach, lentils — supports blood volume expansion
  • Calcium: Dairy, fortified plant milk, leafy greens — fetal bone development
  • DHA (omega-3): Low-mercury fish (salmon, sardines), walnuts — brain development
  • Vitamin D: Sunlight, fortified foods — calcium absorption and immune function

Your provider may recommend a calorie calculator or dietary assessment based on your pre-pregnancy BMI and any gestational weight-gain targets.

Summary

The first trimester sets the foundation for the entire pregnancy. The priorities are: confirm the pregnancy and EDD (use the Pregnancy Due Date Calculator for a quick estimate), book prenatal care early, start folic acid immediately, avoid high-risk foods and substances, and complete first-trimester screening by week 13. Above all, maintain close contact with your healthcare provider — every pregnancy is unique, and personalised guidance is irreplaceable.

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Frequently Asked Questions

When should I book my first prenatal appointment?
Book as soon as your pregnancy is confirmed — ideally before 8 weeks. Your provider will schedule your first visit (the 'booking appointment') between weeks 8 and 12.
Is it safe to exercise in the first trimester?
For most pregnancies, moderate exercise is safe and beneficial. Walking, swimming, and prenatal yoga are generally recommended. Avoid contact sports, high-impact activities, and anything with fall risk. Always check with your provider first.
What foods should I avoid in the first trimester?
Avoid raw or undercooked meat and fish, unpasteurised dairy, raw sprouts, high-mercury fish (shark, swordfish, marlin), excessive caffeine (limit to 200 mg/day), and alcohol. This list is not exhaustive — your provider will give personalised guidance.
Are miscarriage risks higher in the first trimester?
Yes. About 80% of all miscarriages occur in the first trimester, with the highest risk before 10 weeks. After 12 weeks, the risk drops significantly. If you experience heavy bleeding or severe cramping, contact your provider immediately.

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