Childbirth - Introduction

The amazing, 40 week process whereby a single cell becomes a fully-formed, living person usually leads to normal, healthy babies born at full-term without too many complications.

But it was not always this way. A hundred years ago in Britain 140 babies and six mothers died for every 1000 live births. Today it is six babies and the risk of a mother dying during pregnancy or childbirth is less than one in 5000.

Children born in Britain today benefit from numerous medical advances in childbirth.

Better nutrition, hygiene and access to healthcare have all played their part in not only reducing serious dangers but also in making labour easier and the pain less intense. As well as medication, incubators and surfactants to help premature babies breathe are amongst the advances that research using animals has helped bring about.

Some major childbirth milestones
1847	First anaesthetics used in childbirth: ether and chloroform
1878	First incubator for premature babies
1930s	Antibiotics caused a dramatic drop in maternal death rate. Discovery of prostaglandins
1960	Popularisation of epidural anaesthesia
1960s	Prostaglandins used for induction of labour
1961	Syntometrine (a mixture of oxytocin and ergometrine) to help deliver placenta introduced in the UK
1961	Apparatus capable of delivering oxygen 50% and N2O 50% (Entonox)
1963	Production of RHOGAM (anti-D immune globin) a molecule that prevents destruction of blood cells in babies whose blood type is different from the mother
1972	Corticosteroid treatment shown to reduce respiratory distress syndrome in premature infants
1975	ECMO - a special procedure that uses an artificial heart-lung machine to take over the work of the lungs (and sometimes also the heart) reduced infant mortality from 80% to 25% in infants with acute reversible respiratory and cardiac failure
1980	Surfactant therapy to help lungs of premature babies work properly
1991	Folic acid reduces the risk of neural tube defects such as spina bifida
1991	Combined spinal epidural ("mobile" epidural) technique developed at Queen Charlotte's hospital in London

Nutrition

The importance of nutrition even before conception, and one of the great success stories of the 20th Century, is folic acid (synthetic form of vitamin B). It helps prevent neural tube defects such as spina bifida. More »

Good nutrition not only helps the developing foetus, it also plays an important role in ensuring mothers are in the best possible shape to deliver.

Other vitamins are important too. As early as the 1930s, studies in pigs showed that vitamin A is essential for a baby's development. But, subsequent research in a variety of different animals also pinpointed the damaging effects of too much vitamin A - it causes birth defects.

In the late 1950s, US researchers working on rats linked retinoic acid, which is made from vitamin A, to birth defects. They noticed some rats were more susceptible to the effects of Vitamin A than others. This was one of the first indications that genetic factors might combine with diet to increase the risk of birth defects.

Babies' healthcare

In 1870, infant death rates reached their peak, with almost one in four babies dying at birth. This appalling level triggered the first attempts to use incubators to help premature babies (born before 37 weeks' pregnancy). Inspired the poultry incubators, early human versions cut death rates by more than half in infants weighing less than 2 kg (4.4 lb). Nowadays, 50% of babies born at 25 weeks of pregnancy survive. More »

Jaundice

Roughly half of newborns experience some jaundice with rates higher amongst premature babies. In most cases, jaundice clears naturally - often with nothing more than the help of a little sunlight. But for others, jaundice can lead to serious health problems ranging from brain damage to death. More »

Blood groups and disease

In the 1940s scientists studying Rhesus monkeys discovered something that was to revolutionise the management of pregnancies: the Rhesus factor (Rh). Most people have this molecule in their blood so their blood group will be e.g O +, where the + refers to the presence of the Rhesus factor.

Rh + babies born to Rh - mothers are at risk of a life-threatening disease where the babies' blood is destroyed because the mother's immune system generates antibodies against the rhesus factor. Called haemolytic disease, it was a major cause of infant death and stillbirth. More »

Helping premature infants breath more easily

At birth, babies make a tremendous transition. They can no longer rely on their mothers to provide oxygen and must start breathing on their own. For many preterm, and some full term, babies this transition does not go smoothly.

As many as half of babies born before 32 weeks develop respiratory distress syndrome (RDS). Two developments had a major impact on reducing death from RDS: the introduction of surfactant therapy and the use of corticosteroids in women likely to give birth prematurely. More »

Maternal healthcare

One half to two thirds of pregnant women experience morning sickness, particularly in the first three months. The cause is not clear, but theories include hormonal changes and fluctuations in blood pressure. Although unpleasant, the good news is that it doesn't usually harm mother and unborn child. However, in more severe cases, it can lead to severe illness. Known as hyperemesis gravidarum, it is characterised by dehydration and weight loss. Women with this condition may need to be hospitalised. More »

Thrombophilias are a group of disorders that promote blood clotting and can complicate pregnancy and lead to recurrent miscarriages. As many as one in five women have thrombophilia - often unknowingly. Women who are over 35 years old, overweight and have a history of a clot are most at risk. Heparin is one product that can be given to reduce the chances of a blood clot. It is injected, but cannot cross the placenta and thus cannot enter the baby's bloodstream. Identified in dogs, it is still largely prepared from animal sources, namely cows and pigs. The safety of each batch is assessed in anaesthetised animals to ensure the absence of substances that might lower blood pressure. A synthetic version of heparin has recently become available.

Epidurals have been used since the 1950s, but are associated with longer labour and surgical intervention. The concept of selective pain relief via spinal injections in the 1980s led to the opioid dose techniques that are now used. Low doses opioid pain killers like fentanyl, morphine and pethidine are combined with local anaesthetic combinations. Rats are usually used to test the blocking abilities of various compounds.

Most of the time pregnant women naturally go into labour: their waters break and contractions start. But one in five has labour induced. Perhaps they are well past the due date, there are potential complications like diabetes, or when the waters have broken too early and labour does not start. More »

Two areas that have remained almost immune to progress are pre-eclampsia and premature labour. Pre-eclampsia, a complex, pregnancy-related condition that includes high blood pressure, is better understood today than fifty years ago, but effective treatments remain elusive. This is, in part, because pre-eclampsia is a peculiarly human disorder and available animal models have not yet led to new treatments. More »

Premature labour accounts for nearly three-quarters of premature births, with most of the remaining quarter resulting because high blood pressure (pre-eclampsia/eclampsia) threatens the baby and the mother's well-being. The UK has one of the highest rates of premature births in Europe, with nearly 49,000 babies born prematurely each year. More »

Next Section: Future prospects