The First Trimester: What to Expect

In the first trimester, the NHS says the earliest and most reliable sign of pregnancy for someone with a regular menstrual cycle is a missed period ¹. The NHS says it is common to feel tired, especially during the first 12 weeks ¹. MedlinePlus says most pregnant women have at least some nausea, and about one third have vomiting ².

Key takeaways

• The NHS says the earliest and most reliable sign of pregnancy for someone with a regular menstrual cycle is a missed period ¹.
• The NHS says nausea and vomiting, often called morning sickness, usually begin around 4 to 6 weeks of pregnancy ¹.
• MedlinePlus says morning sickness most often continues through the 14th to 16th week ².
• MedlinePlus says most pregnant women have at least some nausea, and about one third have vomiting ².
• The NHS says needing to urinate more often than usual, including at night, is a common early pregnancy symptom ¹.
• MedlinePlus says to contact your provider immediately if you vomit blood or material that looks like coffee grounds ².

Urgent: early-pregnancy warning signs

**MedlinePlus says to contact your provider if morning sickness does not improve despite home remedies, if nausea and vomiting continue beyond your fourth month, if you vomit more than 3 times a day or cannot keep food or liquid down, if your urine is dark or you urinate very infrequently, or if you have excessive weight loss, and to contact your provider immediately if you vomit blood or material that looks like coffee grounds ². MedlinePlus says severe chest pain or shortness of breath that does not go away can be a sign of a serious medical complication, and to call 911 or the local emergency number or go to an emergency room right away if you have these symptoms ³. MedlinePlus says that if you have pain when you urinate or a change in urine odor or color, to contact your health care provider, because these could be signs of a bladder infection ³. In the UK, the NHS says that if you are being sick all the time and cannot keep anything down, to see a GP, because you may have hyperemesis gravidarum, a serious condition in pregnancy that causes severe vomiting and needs treatment ¹.**

**A quick, honest note:** we're not medical professionals - everything here was researched by us from the public sources listed at the bottom of this page, and it isn't professional advice. Read our full note ↓

What are common first trimester symptoms?

The NHS says the earliest and most reliable sign of pregnancy for someone with a regular menstrual cycle is a missed period ¹. The NHS says it is common to feel tired, or even exhausted, especially during the first 12 weeks or so ¹. MedlinePlus says, "Being tired is common during pregnancy" ³. The NHS says breasts may become larger and feel tender, just as they might do before a period ¹. The NHS says needing to urinate more often than usual, including at night, is a common early pregnancy symptom ¹. The NHS says nausea and vomiting, often called morning sickness, usually begin around 4 to 6 weeks of pregnancy ¹. MedlinePlus says most pregnant women have at least some nausea, and about one third have vomiting ².

When does morning sickness start and stop?

The NHS says nausea and vomiting, often called morning sickness, usually begin around 4 to 6 weeks of pregnancy ¹. MedlinePlus says morning sickness most often starts in the first month of pregnancy and continues through the 14th to 16th week ². MedlinePlus says, "Most pregnant women have at least some nausea, and about one third have vomiting" ². For severe sickness, the NHS says that if you are being sick all the time and cannot keep anything down, to see a GP, because you may have hyperemesis gravidarum, a serious condition in pregnancy that causes severe vomiting and needs treatment ¹.

Is it normal to pee more in early pregnancy?

MedlinePlus says, "Early on in the pregnancy, you will likely be making more trips to the bathroom" ³. The NHS says needing to urinate more often than usual, including during the night, is a common early pregnancy symptom ¹. There is one caveat: MedlinePlus says that if you have pain when you urinate or a change in urine odor or color, to contact your health care provider, because these could be signs of a bladder infection ³.

When should I see a doctor in early pregnancy?

MedlinePlus says to contact your provider if morning sickness does not improve despite home remedies, if nausea and vomiting continue beyond your fourth month, if you vomit more than 3 times a day or cannot keep food or liquid down, if your urine is dark or you urinate very infrequently, or if you have excessive weight loss, and to contact your provider immediately if you vomit blood or material that looks like coffee grounds ². MedlinePlus says severe chest pain or shortness of breath that does not go away can be a sign of a serious medical complication, and to call 911 or the local emergency number or go to an emergency room right away if you have these symptoms ³. MedlinePlus says that if you have pain when you urinate or a change in urine odor or color, to contact your health care provider, because these could be signs of a bladder infection ³. In the UK, the NHS says that if you are being sick all the time and cannot keep anything down, to see a GP ¹.

Frequently asked questions

What are common first trimester symptoms?

The NHS says the earliest and most reliable sign of pregnancy for someone with a regular menstrual cycle is a missed period ¹. The NHS says it is common to feel tired, especially during the first 12 weeks ¹, and that breasts may become larger and feel tender ¹.

When does morning sickness start and stop?

The NHS says morning sickness usually begins around 4 to 6 weeks of pregnancy ¹. MedlinePlus says it most often starts in the first month of pregnancy and continues through the 14th to 16th week ².

Is it normal to pee more in early pregnancy?

MedlinePlus says that early in pregnancy, women commonly need to urinate more frequently ³. The NHS says this need can include the night ¹. MedlinePlus says that if you have pain when you urinate or a change in urine odor or color, to contact your health care provider, because these could be signs of a bladder infection ³.

When should I see a doctor in early pregnancy?

MedlinePlus says to contact your provider if morning sickness does not improve despite home remedies, or if you have excessive weight loss ². In the UK, the NHS says that if you are being sick all the time and cannot keep anything down, to see a GP ¹.

A note from us

We're the team behind Yael & Michal. We are not doctors, nurses, lactation consultants, or psychologists, and nothing here is professional advice.

Everything above was researched by us from public, reputable sources - we name and link every one of them below - and summarized as carefully as we could, as a free resource for other mothers. We do this because we wished something like it had existed for us.

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Sources

1. NHS. https://www.nhs.uk/pregnancy/trying-for-a-baby/signs-and-symptoms-of-pregnancy/ (retrieved 2026-07-10).
2. MedlinePlus. https://medlineplus.gov/ency/article/003119.htm (retrieved 2026-07-10).
3. MedlinePlus. https://medlineplus.gov/ency/patientinstructions/000583.htm (retrieved 2026-07-10).