Pregnancy Symptoms Week One: What to Expect

Pregnancy symptoms in week one are not something you can feel, because in week one you are not actually pregnant yet. Doctors date pregnancy from the first day of your last menstrual period, so week 1 is simply your period.

Ovulation usually happens about two weeks later, and conception can follow. The fertilized egg then implants in the lining of the uterus during week 3 or so, and only then does the body start making the pregnancy hormone hCG.

Home pregnancy tests detect hCG in urine. The NHS week 4 pregnancy guide says some tests can show a result after about three and a half weeks, and a missed period is a good time to test if you have had unprotected sex.

Early pregnancy symptoms vary from woman to woman in timing and strength, and some women have none at first. Most are normal, but talk to your doctor or midwife if anything worries you.

Symptoms of Pregnancy in the First Week

Anything you feel in week one comes from your menstrual cycle, not from a pregnancy. The pregnancy symptoms below are the early signs to watch for in the weeks that follow, usually from around week 4. Signs that lists of pregnancy symptoms week one often include are

1- A Missed period

A missed period is often the first sign of pregnancy. After implantation, the placenta starts making hCG, which keeps the uterine lining in place so no period comes.

hCG becomes detectable in urine after implantation, so a home test is usually reliable from about the time your period is due. Take a test then, rather than in the second week of pregnancy, when it is too early.

2- Vaginal Bleeding

In week one, any bleeding is your normal period. Later, around the time your next period would be due, some women notice light spotting when the fertilized egg implants. This is called implantation bleeding and is much lighter than a period.

Spotting often appears in lists of pregnancy symptoms week 1, but it can also signal a problem. Report any bleeding in pregnancy to your health care provider, and seek urgent care if it is heavy or painful.

First Week Symptoms of Pregnancy

3- Nausea, Vomiting

Nausea, with or without vomiting, usually starts around week 4 to 6, not in week one. It is caused by rising pregnancy hormones and can happen at any time of day. Call your doctor if you cannot keep food or fluids down.

4- Backache, Low Back Pain

Back pain is common later in pregnancy as the uterus grows and posture changes. In the first weeks it is more likely to be linked to your period. Ask your doctor before taking any pain medicine if you might be pregnant.

5- Headaches

Headaches can happen around your period and also in early pregnancy because of hormone changes. Rest, fluids and a cool pack may help. If you could be pregnant, check with your doctor or pharmacist before taking any pain reliever.

6- Swollen Breast

Sore, swollen and tender breasts are a common early sign of pregnancy, usually from around week 4. Rising progesterone and estrogen cause these changes. Breast tenderness before a period can feel very similar.

7- Constipation

Constipation is common in early pregnancy, though not in week one. An increase in progesterone hormone slows food through the digestive tract, so more water is reabsorbed and stools become harder. Read more: Pregnancy Symptoms Week 1 What to Expect