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What to Expect in the 4th Week of Pregnancy

Learn what to expect in your 4th week of pregnancy.

Learn what to expect in your 4th week of pregnancy.

A Positive Pregnancy Test

The fourth week of pregnancy is usually the time a new mother suspects she may be pregnant. This is the week a menstrual cycle will be due and missed if there is a pregnancy. For women who have been trying to conceive, the missed cycle will be a very welcome sign! Most pregnancy tests will generate an accurate result on the first day of a missed period.

Now that a new pregnancy has been confirmed, what are the next steps? A woman should:

  1. Call her doctor (obstetrician/gynecologist or general practitioner, depending on the medical system).
  2. Start taking prenatal vitamins, if she hasn't already been taking them.
  3. Avoid alcohol and other environmental toxins.
Congratulations! Many women will obtain a positive pregnancy test when they are four weeks pregnant.

Congratulations! Many women will obtain a positive pregnancy test when they are four weeks pregnant.

How the Baby is Developing

When doctors state a woman is "four weeks pregnant," they are indicating the time since the woman's last menstrual cycle. The developing embryo is only 2 weeks old from the time of conception.

The baby is approximately the size of a poppy seed, and has developed two distinct layers. The epiblast is a disc shaped layer, which is also called the "inner cell mass." This layer will form the embryo. The hypoblast will form the yolk sac, which will nourish the developing baby until the placenta is functional.

In a short period of time, an important process called gastrulation will occur (at around 5 weeks of pregnancy). The epiblast will completely reorganize itself into a three-layered structure. This early stage of embryogenesis is critical for proper organ development in the baby - from now until approximately 10 weeks of pregnancy, all of the baby's organs will be formed. Environmental toxins are at their most dangerous during these early weeks of pregnancy.

The Developing Gastrula

When the blastula folds inward, the gastrula is formed. Unlike the single-layered blastula, the gastrula contains three distinct layers.

When the blastula folds inward, the gastrula is formed. Unlike the single-layered blastula, the gastrula contains three distinct layers.

How the Mother Will Feel at Four Weeks

Some women will feel no symptoms of pregnancy at this stage, while others will begin to feel the common signs of early pregnancy:

  • Bloating
  • Nausea
  • Sore breasts
  • Fatigue
  • Frequent urination

There are other symptoms of early pregnancy that are more vague. Many women will get headaches during this time. Constipation or diarrhea may also make an appearance, which can make the woman uncomfortable. Acne may increase and appear on the face, arms, and back. Veins may become prominent and look like a "road map" on a woman's chest. Irritability and emotional swings are also common.

Headaches in Early Pregnancy

Common Concerns: Cramping and Spotting

Some women will experience "pinches and pulls" in the uterus. This is often normal: the uterus is already beginning to grow and there may be some small pinching pains every once in a while. In addition, up to 1/3 of women will experience spotting during early pregnancy. This is sometimes caused by the release of "old blood" from implantation, though all spotting should be reported to the woman's physician immediately.

About 1/2 of all women who have spotting in early pregnancy will experience a miscarriage, though the other half will deliver healthy babies. Spotting that turns into frank bleeding, often accompanied by cramps, is generally a sign of an impending miscarriage. Spotting brown blood is less worrisome, but should still be reported. A "viability" ultrasound may be performed as the pregnancy progresses to determine if there is a heart beat at around 6 weeks of pregnancy. Beta hCG numbers may be obtained through a blood test - the hCG numbers should double every 48-72 hours. A drop in beta hCG levels indicates an impending miscarriage, while hCG levels that rise at the appropriate rate indicate the pregnancy is continuing.

Nature Made Prenatal Vitamins

Types of Prenatal Vitamins

Prenatal vitamins may be obtained over-the-counter or by prescription. There are many different formulations available - the most important nutrient to consider at an early stage of pregnancy is the amount of folic acid in the vitamin. A prenatal vitamin should contain at least 400 mcg of folic acid: this will help prevent neural tube defects in the developing baby. Many formulations contain 800 mcg to further ensure a sufficient supply of this vital nutrient. Women who have had a prior pregnancy with a neural tube defect should consult their doctor immediately, as a very high level of folic acid may be recommended to prevent future occurrences.

Many prenatal vitamins are now formulated as soft gel tablets. Chewable, liquid, and standard tablet forms are also available. Read the ingredient label carefully to ensure there are no additional herbs included in the recipe, as herbal concoctions are not recommended in early pregnancy (discuss any herb usage with a doctor prior to pregnancy, as some herbs are toxic to a developing embryo).

Docosahexaenoic Acid, or DHA, is often added to prenatal vitamins. This fatty acid is known to assist with brain and eye development. Some vitamin packages come with a separate DHA capsule, which must be swallowed in addition to the prenatal vitamin. Some prenatals are formulated with the DHA incorporated into the main vitamin pill.

In early pregnancy, it may be difficult to stomach the vitamins. If nausea is a problem, try taking the vitamins in the evening. Taking two Flintstones chewable vitamins is another option: these vitamins have the equivalent nutrients to a prenatal vitamin, and are more palatable and tolerable for some women.

Prenatal Vitamin Checklist

Every prenatal vitamin should contain these nutrients.


Folic Acid

400 mcg (minimum)

Prevents neural tube defects


17 mg

Prevents anemia in the mother


15 mg

Necessary for DNA repair and immune system function

Vitamin D

400 IU

Helps to build baby's bones and teeth


300 mg

Necessary for bone development

Vitamin C

70 mg

Antioxidant; also used to form collagen

Vitamin E

10 mg


Riboflavin (Vitamin B2)

2 mg

Helps with growth, skin, and energy production

Thiamine (Vitamin B1)

3 mg

Brain development, muscle development


20 mg

Brain development.

Vitamin B12

6 mcg

Brain and nervous system development

What to Expect at the Doctor's Office

Many doctor's offices will have a newly pregnant woman come in to fill out paperwork and to set the date for the first appointment. Some doctors may schedule an appointment early in the pregnancy, though many doctors may not see a woman for a physical and first ultrasound until she is 8-10 weeks pregnant. In some offices, only one ultrasound may be ordered at approximately 18-20 weeks of pregnancy.

Women who have had prior miscarriages, are spotting, or are otherwise concerned about their pregnancy should let the office staff know up front, particularly if the doctor's office in question does not see women until they are at the end of their first trimester. A viability scan may be ordered at 6-7 weeks gestation to monitor the pregnancy and detect the embryo's heart rate.

This content is accurate and true to the best of the author’s knowledge and does not substitute for diagnosis, prognosis, treatment, prescription, and/or dietary advice from a licensed health professional. Drugs, supplements, and natural remedies may have dangerous side effects. If pregnant or nursing, consult with a qualified provider on an individual basis. Seek immediate help if you are experiencing a medical emergency.


Leah Lefler (author) from Western New York on October 16, 2012:

What a fantastic pregnancy, Hyphenbird! I was very nauseated from about 5 1/2 weeks-11 weeks of pregnancy, but never threw up. I was so fatigued I could hardly function in the first trimester, but then things were perfect after I entered the second trimester.

Brenda Barnes from America-Broken But Still Beautiful on October 15, 2012:

I had a wonderful pregnancy. I was not sick, only threw up once. I had no headaches, no swelling, nothing. It was perfect and that makes me happy since I never hadanother child. Thanks for another wonderful and informative Hub.

Leah Lefler (author) from Western New York on October 14, 2012:

The first weeks of pregnancy can be stressful and confusing, lindacee! I was always so grateful to get to the second trimester with my pregnancies. I remember being worried when there were no pregnancy symptoms (and then regretting that worry when the morning sickness showed up, haha)!

Linda Chechar from Arizona on October 13, 2012:

Even though I've not had children myself, I've lived through the experience with several friends who have. This Hub should be required reading for all new moms. It will certainly answer a lot of questions as they go through the initial weeks of pregnancy!

Leah Lefler (author) from Western New York on October 13, 2012:

I remember the fatigue and nausea the most, Eiddwen. I was a literal zombie with my two sons - the second trimester was a welcome relief!

Eiddwen from Wales on October 13, 2012:

Oh yes I remember it well ha!!!

This hub is well informed will benefit many. A great share and enjoy your weekend.


Leah Lefler (author) from Western New York on October 13, 2012:

The miscarriage rate is still fairly high at four weeks of pregnancy (about 15% for women under the age of 35 and 30% for women 35-38 years old). The rate drops considerably once fetal heart tones are detected at about 6 weeks of pregnancy, and are very, very low once you reach 10 weeks of pregnancy. With early detection pregnancy tests, some women are detecting their pregnancy at 3 weeks, which is only 1 week after conception! I found out I was pregnant with both of my boys at the four week point, as I always waited until I was "late" to test.

The physical changes can be startling, Teaches12345! I remember being shocked at how fatigued I was early on. I could sleep during the entire day (and then wake up at 3am for no apparent reason)!

Dianna Mendez on October 12, 2012:

I remember the veins looking this way and thinking that they would permanently mar my body. It is such a big change from the first weeks of pregnancy. I always believe that if you make it through to this week the chances of miscarriage diminish. Great hub post and very informative. Voted up.