Pregnancy Week by Week:
What to Expect Week 1-4

Congratulations on your pregnancy! You’ve just started a journey that will completely transform your life forever.

In our Pregnancy Week by Week series, we are going to highlight everything you can expect for you and your little one through every step of this journey. We’ll break it down week by week for your convenience. With each week, you’ll also get useful advice you can use throughout your pregnancy.

This first guide in the series will focus on the earliest pregnancy weeks. Many women may not even know they are pregnant at this stage. However, if you suspect you might be, this guide will help you figure out what you can do to know for sure. We’ll also tell you exactly what is going on in your body if you are pregnant.

Your pregnancy weeks are counted from the first day of your last period. Doctors do this because it is difficult to know for sure the exact moment when conception occurred. Here is a look at what goes on during the first four weeks.

Week 1

What to expect for baby

Technically, you’re not even pregnant on week one. However, this week is counted because it is the first week of your last period and it contributes to your due date at week 40. For now, the most important thing to know is when the first day of your last menstrual period (LMP) was.

Fertilization won’t occur until late in week 2 or early week 3. For now, the sperm and egg have not met yet, so your baby is just about to start being formed. In a few days, one of your eggs will be released from your ovaries and the sperm will fertilize it, and you will officially be pregnant!

If you’ve just found out you’re pregnant, you are likely in your 4th week of pregnancy. However, your doctor will give you a more accurate estimate.

What to expect for mom to be

Since you have not conceived yet, you likely won’t notice any symptoms or differences in how you feel. If you are planning to get pregnant, this preconception period should be all about taking the best care of yourself. You want to start preparing for your pregnancy as early as now.

Over the first week, your uterine wall will thicken to get ready for pregnancy. When ovulating, your vaginal discharge can be sticky. At the start of your period, about twenty ova occupy fluid-filled sacs known as follicles. If you usually have your period every 28 days, you ovulate about 14 days later. During ovulation, one of the follicles releases 1 or 2 ova, and they travel down the fallopian tubes to await fertilization.

Tip of the week

As mentioned earlier, the first week is all about preparing for pregnancy. Start eating a balanced and nutritious diet, getting enough sleep, and staying active by getting some exercise. You can also get started on a prenatal vitamin if your healthcare provider recommends it. Most importantly, start taking better care of your overall health and avoiding substances like alcohol and cigarettes to encourage quicker conception and much healthier pregnancy.

Week 2

What to expect for baby

Fertilization will occur sometime in week 2 or in early week 3. Sperm swims up to meet the egg in the fallopian tube. When a single sperm manages to penetrate the egg cell, fertilization occurs.

The egg has half the genetic information needed to create a human while the sperm has the other half. They exchange this genetic information (in the form of chromosomes) and unite, leading to the formation of a zygote.

As this happens, the fertilized egg starts to make its journey down the fallopian tube towards the uterus. While it does this, it is also rapidly dividing. The zygote divides into two cells 12 hours after conception, then more and more cells over the next few days. This journey and division will take place through most of week 3.

What to expect for mom to be

If you have not been actively trying to conceive, you may not even know that you are pregnant at this stage. You likely won’t experience any major symptoms as well. However, some women notice spotting, fatigue, tender breasts, frequent peeing, and increased aversions to certain foods at this stage.

You are most fertile 14 days and one or more days after your period starts. If you recently stopped using contraceptives, you can ovulate sooner than you expected. After the egg becomes fertilized (about 1 to 3 days after ovulation), it begins its journey towards the womb.

Tip of the week

IIf you are trying to get pregnant, consider taking 400 micrograms or 0.4 milligrams of folic acid daily. Research shows that taking folic acid supplements a few months before conceiving dramatically reduces neural defects like spina bifida.

Week 3

What to expect for baby

By week 3, the sperm and ovum have joined to form the zygote, which is about the size of a pin’s head. The zygote has been subdividing for a while into smaller and smaller cells while moving towards the uterus. It takes about 3 to 6 days for the zygote to move from the fallopian tube to the uterus.

More cell division will occur in the uterus, leading to the formation of a hollow ball of cells called a blastocyst. In about 8 weeks, this will become the embryo. For now, though, it is a group of about 100 cells that are growing and multiplying rapidly. The cells on the outer layer will become the placenta while the cells in the inner layer become the embryo over the next weeks.

What to expect for mom to be

At this stage of pregnancy, you will not notice any changes in your body. Note that you will also not have missed your period yet. However, hormones will signal your body to cease the menstruation process and support your pregnancy.

That said, you may experience more of the symptoms you had in week 2, including increased urination, moodiness, swollen and tender breasts, bloating, and fatigue. These symptoms occur because your body is producing more estrogen and progesterone hormones. You may also experience cramping and spotting caused by the implantation of the zygote into the uterine wall.

Some women also notice some white vaginal discharge as the uterine walls thicken. Because of this, it is easy to confuse these early symptoms with normal PMS symptoms. Plus, if you take a pregnancy test now, you may get a negative result because your hCG hormone levels are still not high enough to register on the test. Give it another week or so then try again.

Tip of the week

If you have not started already, prenatal vitamins should be at the top of your to-do list. Take at least 400 mcg/day to give your little on a developmental boost. Also, ensure you are getting other essential vitamins and minerals from your diet, including calcium, iron, DHA, and Vitamin D.

Week 4

What to expect for baby

Implantation occurs sometime in week 3, so by week 4, your growing baby will have burrowed into your uterine lining. By now, the embryo has two layers of cells known as the epiblast and the hypoblast. Your baby is about as a poppy seed. Be sure to reach out to your health care provider and start scheduling prenatal visits. 

What to expect for mom to be

You may be expecting your period this week. If it fails to occur, this could be a sign of pregnancy. Consider taking a home pregnancy test just to be sure. By the end of week 4, most home pregnancy tests will be positive.

You may also experience slight spotting as the implantation process comes to an end. Your baby’s amniotic cavity will be full of fluid, and the placenta will be forming in your womb.

As for you, though, you may not feel any difference at all. However, some women have tender breasts and a bit of nausea.

If you have found out you are 4 weeks pregnant, you’ve known a lot earlier than most women do. Share the news with your partner but it’s probably wise to wait a while before telling everyone else.

Tip of the week

You can perform a home pregnancy test at the end of week 4. This test is almost as reliable as a blood or urine test performed in a doctor’s office. You will obtain the results immediately. Read the directions on the home pregnancy test kit carefully and use clean supplies to take the test.

While you usually don’t have your first ultrasound until you hit the 6-week mark at the very least, you might be able to spot the gestational sac as early as halfway through the fourth week.

From now on, it is essential to eat healthily. This means selecting various foods from the recommended food groups and drinking 6 to 8 glasses of water or more daily. However, you do not need to increase your food consumption significantly. You only need an additional 300 calories daily while pregnant. Your food intake will actually probably drop in the beginning due to morning sickness, but you do not need to worry about that. If you eat properly and continue to do so, your growing baby will get all the nutrients they need.

Final Thoughts

For most women, learning that there is a bun in the oven is a moment of pure joy. That’s why we just want to give you a hearty congratulations from all of us at Momanda!

With this guide, you should now know exactly what to expect from the 1st to the 4th week of pregnancy. Make healthy choices such as eating a healthy diet, avoiding potentially harmful substances like alcohol and tobacco, reducing your stress levels, and getting enough sleep every night (6 to 8 hours) to give your little one the best start in life.

Also, do not forget to make an appointment with your healthcare provider to start monitoring your pregnancy. Finally, expect lots of changes to happen to your body over the next few weeks, so start planning to invest in the right pregnancy sleepwear and nursing bras that’ll make your life easier.

Angelia Smith - Feb. 18 2022