Pregnancy is one of the exciting things that happen to mothers, and the most exciting thing is the occurrence of a twin pregnancy. In this article, we will provide you with all the necessary information about a twin pregnancy, the stages of formation of a twin fetus, and how does a twin pregnancy occur? Follow us reading to find out all this information.

How do you get pregnant with twins?

Sometimes a twin or triple pregnancy occurs, and in other cases, there are specific factors that trigger the existence of twins. For example, the possibility of having a twin pregnancy increases as you get older because hormonal changes can cause more than one egg to be released at a time. The use of assisted reproductive technologies, such as in vitro fertilization, also increases the odds of having twins.

Types of twin fetuses

Differentiated twins, the most common type of twins, occur when two separate eggs are fertilized by two different animals. Each fetus has a placenta and an amniotic sac. The twins can be two girls, two boys, or a boy and a girl.

Identical twins occur when a fertilized egg divides and develops into two fetuses. Identical twins may share a placenta and amniotic sac, or they may only share a placenta. In complete separation into two individuals, these babies are known as conjoined twins.

Stages of formation of twin fetuses in the womb

Here are the stages of twin fetus formation in detail:

• After 3 weeks of pregnancy in the case of different twins, the fertilized egg of each fetus develops, is divided into hundreds of cells, and each egg is implanted in the wall of the uterus, while in the case of identical twins, one egg is divided.
• In the fourth week: the embryos develop, consisting of two layers of cells that develop little by little to form the internal organs such as the heart, and the buds that form the limbs.
• By the fifth week, both the placenta and the amniotic sac are formed for each twin, depending on the type of twin, as two different placentas and two sacs are formed in the case of the different twins, while for identical twins the same placenta and two different sacs are formed, or one sac (in rare cases).
• After 8 weeks: Each fetus has two arms and two legs, fingers and genitals begin to form, nerve cells branch out from the brain to connect with each other, and the spinal cord is formed. Their heartbeats can be heard, and major organs, including the lungs, are developing.
• In the 12th week, the embryos move, but you still do not feel it, the nails develop, and facial details begin to appear, such as the development of the eyes, eyelids, nose, and upper lip, and the development of bones.
• After 16 weeks: a light hair grows on the head of each of them, and you can see the genitals by ultrasound.
• Week 20: The twins’ ears are developing, and they may be able to hear. Eyebrows and eyelashes are formed, and nails become solid to the point of increasing the possibility that one of the fetuses will scratch himself by mistake. During that period, you can identify the sex of the twins by means of sonar, and the size of the fetuses can be measured, and the heartbeat of each of them can be followed. In addition, the substance that consists of digestive secretions, amniotic fluid, some cells, etc. is formed and is considered the first bowel movement of the baby after birth.
• Week 24: Skin turns red, eyelashes grow longer than before, their tiny bodies begin to store fat, taste buds form, and bone marrow begins to form blood cells. At that point, the testicles descend for male fetuses, and the ovaries are filled with eggs for females.
• Week 28: The brain of each of them grows rapidly, the lungs develop more and more, the twins can open their eyelids, layers of fat accumulate under the skin, they can make some movements, and half their fingers.
• Week 32: Bones are fully formed, but still fragile, nails are fully developed, and the fetus is breathing regularly. The control of body temperature is the last to develop, but it is rapidly developing thanks to the development of the brain.
• Week 36: Most twins are born in this period of time, as the lungs are complete, and all body systems are working well. In the last period of pregnancy, the weight of the fetuses increases through the accumulation of layers of fat, which increases the weight of the children to the normal weight at birth.

At the end of the article, after knowing the stages of formation of the twin fetuses, and the reasons for the formation of twins, you should always consult a doctor to ensure the correctness of the development of the fetuses, and monitor your health to avoid the risks of a twin pregnancy.