First Month Pregnancy – Belly, Body, And Other Changes

If you are reading this and you are pregnant, welcome to the pregnancy club! Most women will not know about their pregnancy in the first month after they conceive. The first prenatal appointment with your doctor will give you a fair idea about pregnancy, especially if it’s your first baby. You will be asked to take a set of tests to identify and detect any complications during the early pregnancy. Your first visit to the doctor would be to make sure about the pregnancy.

The OB-Gyn will calculate the due date from the first day of your last menstrual period, assuming a 40-week-long pregnancy. But the conception – sperm fertilizes the egg – happens only two weeks after your period.


First Month Pregnancy Changes

In the first trimester, the conception and implantation begin. By the end of the first month, the yolk sac, amniotic sac, and umbilical cord will begin to develop. The embryo will be approximately 2 mm in length.

The only indication of your pregnancy would be your missed period and there won’t be any significant change in the size of your belly. The uterus which is right behind the bladder will be there until 5-6 weeks of gestation and slowly moves forward and upward. Any pregnant woman will relate to frequent urination. This is because of the uterus pressing the bladder. Other symptoms of pregnancy are fatigue, sore breasts, morning sickness, vaginal discharge, and constipation.


Fertilization And Implantation

The sperms swim up the uterus to the fallopian tubes and remain in it for four days. When the sperm meets an egg from ovaries, it penetrates and conception or fertilization happens. Then the fertilized egg divides into identical cells and goes back toward the uterus. These cells when they try to settle and implant into the womb, some women may experience implantation bleeding. It happens about 10-14 days after conception. This bleeding could be confused with menstrual bleeding by some, but implantation bleeding is typically light and lasts only 1-2 days.

The Development

Although the pregnant belly does not show any change in the first month of pregnancy, you will probably not know the immense amount of development inside your belly. When the fertilized egg penetrated the uterine lining it is called blastocyst. This splits into two groups of cells. The cells which develop into the actual embryo and the cells which get embedded in the uterine wall which will later become the placenta. Essential nutrients go to your little one through the placenta and the waste from the baby are also removed through the placenta. An ultrasound, particularly a transvaginal ultrasound done through the vagina will reveal the gestational sac in which the baby would grow.


The embryo starts taking shape and the basic circulatory system, the heart will be formed. A neural tube which eventually becomes the central nervous system – brain and spinal cord – will form. Folic acid is very important for the development of baby’s neural tube.

Hormonal Changes

As much as body changes, even hormonal changes happen during pregnancy. First seven weeks of pregnancy, the progesterone maintaining the uterine lining is secreted by the ovaries. This hormone progesterone is responsible for many symptoms during pregnancy like tingling sensation in the breasts, sore nipples, constipation, nausea, indigestion, and gastric reflux. Your emotions go haywire because of hormonal fluctuations. One minute you will be very happy and the next will be followed by an unexplained sadness. This is completely normal. These wild hormonal changes will also make your appetite go for a toss. Nausea, morning sickness is generally in the first trimester. You will feel dizzy or nauseated with certain fragrances, foods, or flavors.


These are the changes that happen inside the pregnant belly in the first month. The yolk sac helps protect and also nourish the embryo until it gets fully developed.