While a lot has taken place between week one and week three, the fourth week is more critical because the embryo will stop attaching on the placenta and begin feeding through the umbilical cord. Besides, it is in the fourth week and fifth week that your pregnancy can be confirmed.

4 Week Pregnant


Baby’s growth and development in week four

In the fourth week, the embryo (embryonic disc) will grow from 2 mm to about 6 mm. The process of internal organs development (heart, blood vessels, and others) that started in the third week will continue more rapidly.

  • Formation of amniotic sac: As the embryonic disc continues growing and extending, it curves inwards so that the outer (peripheral tissues) tissues form the amnion membrane becoming a sac that will house the embryo for the remaining part of pregnancy. This will fill with a protective fluid (amniotic fluid) to cushion the embryo during the entire pregnancy period.
  • Formation of the umbilical cord: Part of the peripheral tissues develops into a simple stock that attaches to the fast developing embryo by the end of 28th week. While the membrane that forms the amnion appears to be loosely attached to the embryo, the stalk (umbilical cord) is deeply rooted and connected to the baby and will be the main feeding line for the developing baby.
  • Days after the formation of the umbilical cord, the feeding mechanism shifts so that the baby no longer feeds from the uterus, butt through the umbilical cord.
  • After the formation of the onion sac, the six-inch baby appears floating freely in the amniotic fluid.
  • By the end of the fourth week, a small tail can be seen bending upwards while the head bends downwards from the upper end. Though the development is tremendous in this week, it is still very early to tell the sex of the baby until later into the coming weeks.

Size of Baby at 4 Weeks Pregnant

Your baby is the size of a poppy seed.

Changes to expect in Mom’s body during week 4

As the embryo continues to grow rapidly, the mother also experiences extensive changes every day of the week. If you are very curious about taking that pregnancy test, go ahead, and it will confirm that you are indeed pregnant. However, the ideal time is the following fifth week when all the pregnancy hormones can be detected in the urine.

  • The body continues to produce a lot of HCG (pregnancy hormone) that cause morning sickness to intensify. You will experience nausea and vomiting more frequently compared to the previous weeks.
  • The elevated level of HCG will also cause a lot of anxiety and possible high headedness.
  • In some people, the diversion of blood to the developing baby can lower supply to the brain and result to fainting. If you notice this, make sure to discuss with the doctor because it can cause physical injuries to you and the developing baby.
  • Dizziness and exhaustion is a common characteristic for most mothers at the fourth week because all the systems are overworked. From the blood, lungs, and kidneys, all organs have gone on an overdrive, and you will even be tired when waking up after a long night.
  • You may lose or gain weight during this week depending on the extent of your appetite shift. If you experience loss of appetite, it is important to talk to a doctor so that all the necessary nutrients are supplied.
  • Other changes to expect in your body include:
    • Headaches
    • Soreness and sensitivity of your breasts
    • Mood swings
    • Food aversions

Things to do during the 10th week

One thing that you will note during this week is that the changes may appear like they are becoming too much. Within just four weeks, you are vomiting, very high headed, and moods keep swinging from one moment to another! Well, take it easy, these are temporary and will go away when the first trimester goes away.

  • Discuss the pregnancy with your spouse so that he can understand and help you get over some of the symptoms. Some might get upset by your mood swings and food aversions.
  • Make sure to change all the negative habits that can compromise the effective development of the baby. These habits may include;
    • Taking alcohol
    • Drugs abuse
    • Extreme sports
  • Take another pregnancy test if you cannot wait to have it done by the end of the following fifth week.
  • Make sure to live a positive lifestyle during the week to enjoy every minute. Even when the symptoms such as mood swings are live, remind yourself that it is only for a very short while and more importantly for your bundle of joy.
  • Participate in mild exercises that help the body to remain active, promote better circulation, and enhance the development of the baby. Good examples include yoga and walking. You might also consider talking to your doctor or fitness expert for a comprehensive pregnancy program.
  • Meet your cover insurance agency to work on finer details of the pregnancy and negotiate for different terms.
  • Carefully record the details of your pregnancy for the fourth week so that the doctor can find it easy to carry various check-ups when you visit. By maintaining a complete diary, it will be easy to look at the history of the pregnancy and solve issues if they emerge in future.
  • Start looking for close friends who are at the same week of pregnancy so that you can share experiences and build an extended friendship. Often, it feels lonely because your husband is away and even when he is around, there are things that only other pregnant mothers will appreciate.
  • While it may appear early, it is to start thinking about various maternity facilities that you consider to get assistance at during pregnancy and even to deliver in.
  • Enjoy yourself and keep your husband happy at all times. This is time to make even more love if you feel like. For some mothers, the elevated pregnancy hormone directs blood to where it matters most, and they feel sexier than ever before. Well, take the time to enjoy it as much as you can because you do not have to worry about pills any more.
  • Consider taking a short flight before the bump starts enlarging because many airlines disallow pregnant mothers. This is your best moment for a short holiday or getaway.