The first 4 weeks of pregnancy
In the first weeks of a pregnancy, your body starts getting ready for a new life. In medical terms, pregnancy weeks are counted from the first day of your last period, which means fertilization itself usually happens a few weeks later.
Here's what typically happens during the first four weeks.
Week 1
Pregnancy is counted from the first day of your last period. Your body is preparing for a new ovulation, but fertilization hasn't happened yet.
Week 2
This is usually the week when ovulation happens. An egg is released from the ovary and can be fertilized if it meets a sperm cell in the fallopian tube.
Week 3
If an egg is fertilized, a zygote forms. That's the very first cell of what may become an embryo. It quickly starts dividing into more cells as it travels through the fallopian tube toward the uterus.
Week 4
The tiny cluster of cells, now called a blastocyst, can attach to the lining of the uterus. This process is called implantation, and it's where pregnancy begins in the biological sense.
This is often the week when a period doesn't show up and many people start to suspect they might be pregnant.
Common early pregnancy symptoms
As your body starts adjusting to pregnancy, some people notice both physical and emotional changes. Symptoms vary a lot from person to person.
- Excitement and joy: Finding out you're pregnant can stir up a whole mix of feelings, often joy and excitement, and sometimes a bit of worry too.
- Tiredness: Rising levels of the hormone progesterone can leave many people feeling unusually tired early in pregnancy.
- Tender breasts: Hormonal changes can make your breasts feel more sensitive or sore, even this early on.
- Nausea: Some people start feeling nauseous as early as week 4-5, but it's more common a little later in pregnancy. Not everyone experiences nausea, though.
- Mood swings: Hormonal shifts can affect how you feel and leave you more emotional than usual.
- Bloating and mild cramping: Some people feel a dull ache or a cramp-like sensation in the lower belly, a bit like period cramps. This can be down to hormonal changes and the uterus starting to adjust to the pregnancy.