The Baby's Support System

This is the baby's home for 9 months of pregnancy. Once the egg is fertilised the ball of multiplying cells embeds itself to the lining of the uterus. The uterus is the size and shape of an upside down pear and during pregnancy it expands to keep the baby secure and protected.

Key words you will need to know:

-Embryo: the word used to describe the developing baby up to eight weeks old.

-Foetus: the word used to describe the developing baby from eight weeks until birth.

The placenta develops during the first 12 weeks of pregnancy. One side is attached to the uterus and the other side to the foetus via the umbilical cord. The placenta is a deep red colour and by the end of pregnancy is 2.5cm thick, 20cm wide and weighs 500g. The placenta plays an important part in the baby's support system.

Main functions of placenta

-Produces hormones that maintain pregnancy

-Acts as a barrier against harmful substances 

-Allows the foetus to eat, breathe and dispose of waste products

-Links the blood supply of the mother to the baby (although the blood supply of the mother and baby never actually mix)

-Pass antibodies from the mother to baby to give some resistance to infections

Inside the uterus is a sac called the amniotic sac that contains the developing embryo/foetus. The main purpose is to ensure the baby grows safely .

There is a warm fluid in the sac is important as with too much or too little fluid the baby will not continue growing.

Why the amniotic fluid is so important; 

-The fluid enables the baby to float freely and allows limbs to stretch in early pregnancy

-The fluid keeps the baby at a constant temperature of 37°C 

-Supports and protects the baby from knocks just like a cushion

This is the baby's lifeline. It connects the baby to the placenta, and it carries blood and nutrients to the baby and removes the waste products. Immediately after birth it is clamped and cut.

The cervix is the 'neck' of the uterus (womb) and is blocked with mucus (mucus plug) to protect the uterus from infections. During labour the mucus comes away and the cervix dilates (gets bigger) to allow the baby to pass through.