First Trimester: Symptoms, To-Dos and What's Normal in Weeks 1-13

How the weeks are counted

• Pregnancy is dated from the first day of the last period, so you are already about 4 weeks pregnant when a test turns positive. After IVF, dating comes from the transfer date.
• An early ultrasound (often 7-12 weeks) gives the most reliable due date. Only a small share of babies arrive on that exact day.
• By the end of week 13 the baby is about 3 in (7-8 cm) long, with all major organs formed.

What your body may be doing

• Tiredness that feels out of proportion, often the strongest you will feel all pregnancy.
• Nausea, with or without vomiting, at any time of day. It usually starts around weeks 5-6, peaks around 9, and eases for most people by 14-16. Having little or no nausea is also normal.
• Sore, fuller breasts; peeing more often; bloating; constipation; a stuffy nose.
• Food aversions, a metallic taste, a strong sense of smell, and moods that swing quickly.
• Mild cramping and light spotting can happen early and are often harmless, but mention them.

Your first to-do list

• Start or keep taking a prenatal vitamin with at least 400 mcg of folic acid.
• Book a first prenatal visit, usually around 8-12 weeks. See the prenatal visits and tests guide for the blood work and optional genetic screening offered now.
• Review every medicine and supplement with your provider or pharmacist. Don't stop a prescribed medicine (for example for depression, seizures or thyroid) on your own.
• Stop alcohol, smoking, vaping and cannabis. If you drank or smoked before you knew, tell your provider; stopping now still helps.
• Learn the food basics in the eating well in pregnancy guide (listeria, mercury, caffeine).
• Keep moving if you feel up to it; see the exercise in pregnancy guide.

Getting through the hard days

• Eat something small every 1-2 hours; keep plain crackers by the bed.
• Rest without guilt. Shorter workdays, earlier bedtimes and help with meals are reasonable asks.
• If nausea makes daily life hard, treatment exists, including vitamin B6 options. See the common pregnancy discomforts guide.

Feelings and telling people

• Joy, shock, worry and ambivalence can all show up in the same week. That is normal, whether the pregnancy was planned for years or a surprise.
• Many people wait until after 12-13 weeks to share the news widely, once the chance of loss drops, but there is no rule. Some prefer to tell the people who would support them through a loss.
• Partners, co-parents and intended parents have their own adjustment too.

When to check in

• Mention spotting, mild cramps, or nausea that is wearing you down at your next visit or by phone.
• Contact your provider the same day for bleeding like a period, or for being unable to keep fluids down for a day.
• See the miscarriage and early pregnancy loss guide if bleeding or cramping is getting heavier.
• If you have severe one-sided belly pain, shoulder-tip pain, or feel faint, call 911; these can be signs of an ectopic pregnancy.