Placental insufficiency

During pregnancy the placenta (afterbirth) is an organ about the size and shape of a dinner plate which extracts from the mother’s blood all the food and oxygen requirement of the baby. It has, until recent years, been believed that when the fetes does not grow properly as in the cases of intrauterine growth retardation that it was the fault of the placenta in not supplying the fetus with all it’s needs. This is what doctors mean when they use the term ‘placental insufficiency’, that the placenta’s function is insufficient to meet the fetus’ full needs to grow properly.

Another situation in which the placenta was thought to be ‘insufficient’ was in supplying the baby with enough oxygen. If this condition is severe enough the display signs of fetal distress or obvious lack of oxygen.

Both intrauterine growth retardation and fetal distress are serious conditions which can lead to the death of the baby if left to progress on their own. Because of this, scientific research has been carried out to try and find out why these conditions occur and what can be done to prevent them becoming serious.

As a result of this research it is now clear the placenta is probably trying to function properly in cases of ‘placental insufficiency’ and that the fault does no lie with the placenta a but with the vessel or arteries which supply the placenta with blood. Early on in pregnancy , cells form the developing placenta enter the arteries of the uterus (womb) and change the elastic walls so that the vessels become much wider. In this way the mother, along with other changes that occur, can supply more blood to the placenta. What is thought to happen in cases of ‘placental insufficiency’ is that some of these changes do not occur in the arteries and the placenta is not supplied with enough blood to meet the baby’s needs. this results in parts of the placenta dying and at the same time the baby not receiving enough ‘food’ or oxygen.

Doctors have tried to detect whether the placenta is insufficient by measuring the levels of various substances produced by the fetus and the placenta in the mothers blood. These methods are, although useful, not always reliable and can lead to misleading results. However, using a special technique called a Doppler ultrasound scan doctors can measure blood flow to the placenta and assess at a very early stage whether or not there are any problems. Along with these techniques fetal distress can be detected using a matching called a cardiotocograph which measures the baby’s heart beat and the contractions of the uterus.

Another form of finding out how well the baby is doing is performed by the mother herself. This method is called the ‘kick test’ and involves counting the number of baby kicks for 1 - 2 hours at the same time each day. If the number kicks starts falling then this may be an indication of the development of fetal distress. This method is best carried out in conjunction with a General Practitioner.

With the development of these techniques and so the early detection of babies who are likely to develop or who have developed intrauterine growth retardation or fetal distress, deaths from these conditions are now decreasing. However, we are still a long way form fully understanding how these conditions are caused and what can be done to prevent them occurring.