Twin Pregnancy Week 4: Symptoms, Baby Size, Body Changes & more

4 Weeks Pregnant with Twins or Multiples

Medically Reviewed By
Dr. Sanjana Sainani (Gynecologist/Obstetrician)
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On discovering the news of the pregnancy and knowing that she has entered the 4th week, most first-time mothers would be eager to know how their baby is growing. Many women tend to look for signs of twin pregnancy at 4 weeks and are curious to know if multiple babies are gestating within them. But, the growth of the embryos around 4 weeks is pretty minimal to make a solid presence of any multiple babies being present in your womb. Even ultrasound will be able to confirm if the pregnancy is with twins or multiples after the 10th week. Ideally, anytime between the 10th and the 14th week of your pregnancy, you should be able to get a confirmation on whether you’ll have twins or multiples.

It is always better to have information on certain things. In this article, we shall talk a little about the implantation of multiple/ twin embryos and their growth in the 4th week of pregnancy. Read on to know more.

Implantation of Twin or Multiple Embryos at 4 Weeks

Around the 4-week mark, the eggs that have been fertilized by the sperms end up reaching the uterus and begin the process of implantation. If there are multiple embryos, these usually occur when more than one egg is released from the ovaries and are fertilized by the sperms, leading to the formation of fraternal twins or triplets. At times, a single egg splits into multiple ones, leading to the formation of identical twins or triplets. These eggs make their home in the uterus, and the embryos begin to grow.

Baby Growth in the 4th Week of Pregnancy

As you begin completing the 4th week of pregnancy, the neural tubes of the babies present in the uterus begin to form. These mark the initial phase for the nerves, spinal cord, vertebrae, and the brain to stem from and begin to grow. The circulation system begins to get a growth impetus as well, as the arteries and hearts start forming. Umbilical cord formation and functioning begin around this time, too.

Pregnacy 4 weeks baby growth

What Size Are the Babies at 4 Weeks of the Pregnancy?

The baby that is present within the uterus is still in the embryonic stage. It is as tiny as a seed (almost 1/25th of an inch, to be precise), while all the physical and inner developments are going on speedily within it. Pretty soon, slight features of the face and the presence of limbs will start appearing over the coming week.

Your body would go through a series of changes after you conceive. Let’s take a look at some of the common changes.

Common Body Changes in Mothers-To-Be

For many women, the 4-week mark is what officially confirms pregnancy and flags of the journey for them. Some specific body changes that occur at this stage are:

  • As the embryos get implanted within the uterus, some women tend to experience light bleeding or spotting. Once the egg has been implanted, the lining of the uterus thickens itself to keep the baby safe, which may cause bleeding and some pain.
  • The placenta will have started forming ar week 3 already. In the 4th week of pregnancy, it will continue forming further.
  • The mucus in the cervical region begins to increase and close it up in the form of a plug, which will stay until the baby is fully grown and ready to be delivered.
  • This also might be the time where some women will miss their period for the first time, and be might get themselves tested to confirm the pregnancy. Combined with nausea and vomiting sensation, these hopes will be fully confirmed.
  • Some mothers-to-be also experience darkening of the areolas as well as increased sensitivity and tenderness in the breasts.

Pregnacy 4 weeks body changes

Let’s take a look at what the pregnancy test would confirm at 4 weeks.

Pregnancy Test At 4 Weeks

Undergoing an ultrasound for twins at 4 weeks of pregnancy might help some doctors confirm their presence, but it generally may not be the result. Many women won’t even get a positive pregnancy test at this stage, despite having the embryos within her. This is primarily due to the levels of the hCG hormone not being high enough to trigger the pregnancy test result. The hCG hormone also restricts the release of any further eggs, since pregnancy has been attained, indirectly boosting the levels of progesterone and estrogen. All these effects work in tandem to prevent a period and stop ovulation as well. Allow yourself the time of at least one week from your expected day of the menstrual cycle to get a pregnancy test done for conclusive results.

So, we know that, at 4 weeks of pregnancy, it is not possible to identify if a woman will be having twins or multiples. However, many believe that pregnancy symptoms could suggest that she is carrying twins or multiples.

Symptoms of Twin or Multiple Pregnancy at 4 Weeks

Compared to other women, the ones who are pregnant with twins or multiple babies could have stronger signs of pregnancy pretty early in their cycle. Some of the strongest symptoms are:

  • A stronger sensation of nausea combined with a frequent urge to urinate.
  • Overwhelming exhaustion all of a sudden as well as increased soreness and swelling of the breasts.
  • Bloating, cramping, fatigue, mood swings, and spotting will also be seen during this time.

Extreme nausea at 4 weeks

Most of these changes could primarily be because of the presence of multiple embryos, which tends to shoot up the levels of progesterone, estrogen as well as estradiol and the HCG hormone in the body.

Whether you are pregnant with twins/ multiples or not, once your pregnancy is confirmed, you must take care of your health. Here are some tips that you may follow for a healthy and happy term.

Pregnancy Care Tips

There are a few tips women should adhere to:


  • Have a repeat pregnancy test if your previous one turns out to be negative.
  • Start a dose of prenatal vitamins.


Dos and Donts pregnancy 5th week

The excitement of being pregnant with multiple babies in the belly can be enticing for any woman. But, each woman will have a different experience while their little ones grow inside them. Make the best of it and take care of yourself since you are on a journey like no other.

Next Week: Twin Pregnancy Week 5

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