Sex determination

Sex determination

The sex of a baby is determined at the time of fertilization.

1. Chromosomes involved:
   • Ovum (female gamete): The ovum from the ovary carries only X chromosomes.
   • Sperm (male gamete): The sperm carries either X or Y chromosomes.
2. Fertilization process:
   • If the X chromosome from the sperm fertilizes the X chromosome in the ovum, the child will be female (XX).
   • If the Y chromosome from the sperm fertilizes the X chromosome in the ovum, the child will be male (XY).
3. Conclusion: The father determines the sex of the baby, as he contributes either an X or Y chromosome through the sperm.

Signs of pregnancy

A woman who has conceived may begin to show the following signs:

1. Missed period: The menstrual cycle stops.
2. Morning sickness: Nausea or vomiting, especially during the early months (2-3 months).
3. Frequent urination: The need to urinate more often.
4. Breast changes: Increase in breast size.
5. Protruding stomach: The stomach begins to protrude as pregnancy progresses.
6. Facial pimples: Pimples may develop on the face in some women.
7. Feeling movements: After about four months, the woman may start to feel the baby moving inside the uterus.

Steps in pregnancy growth

1. Fertilization and early development: After fertilization, the resulting zygote develops into an embryo and begins to slowly move towards the uterus for implantation.
2. Implantation and formation of the placenta:
   • After implantation, the embryo grows and becomes a fetus. During this period, the placenta is formed and attaches itself to the upper part of the uterine wall.
   • The placenta facilitates the exchange of oxygen and nutrients from the mother to the fetus, and also allows waste products to pass from the fetus to the mother.

Digestive and gaseous exchange system

3. Formation of the heart: After five weeks, the fetus's heart is formed. The heart begins to pump blood throughout the fetus's body.
4. Resembling a child: After two months, the fetus takes on a more recognizable form and resembles a child.

Foetus implanted in the uterus

5. Continued growth and development: The fetus continues to grow inside the mother's womb. The uterus expands to accommodate the growing fetus. This process continues for the full term of nine months, at which point the baby is ready to be born.

Foetus developmental stages

Signs and steps of birth

A few days before birth, the fetus turns its head downwards towards the cervix. The muscles of the uterus begin to contract and relax more frequently. The following signs indicate that the pregnant woman is approaching delivery:

1. Labor pains: Contractions of the uterus muscles begin slowly and increase in intensity as delivery approaches.
2. Fluid discharge: Watery fluid mixed with blood may be discharged through the vagina.

The birth process

During birth, the child is pushed from the uterus through the vagina. The following occurs during the process:

1. Position of the baby: Usually, the head comes first during delivery.
2. Cutting the umbilical cord: The umbilical cord is cut to separate the baby from the mother.
3. First breath: The baby takes its first breath immediately after birth and begins to cry. Crying is a good indicator that the baby is alive.
4. Delivery of the placenta: The placenta is expelled after the baby, known as the "afterbirth."

Important note: If the placenta remains in the mother's uterus, it can cause life-threatening complications, including infections and excessive blood loss.