I know this is something that every mother worries about, but I can't stress strongly enough that such problems are very, very rare, so please try not to be too anxious. The cause of many fetal defects is still unknown. Some may be caused by a defective gene (see Genetic counselling) while others could be due to the harmful effects of drugs, radiation, infections of the baby in the womb, or metabolic disturbances.
There are a number of different kinds of defects - most are very rare. The parts of a baby's body that are most actively growing at the time when the damaging factor happens are the most likely to show the defect. Some malformations are incompatible with life, and no treatment is possible. The defects that are especially important to recognize just after birth are those that endanger life but, with prompt intervention, can be treated successfully. The good news is that an increasing number of problems are now picked up by ultrasound scans before birth and many can be treated just after birth or later in infancy.
This means that the anus is sealed, either because there's a thin membrane of skin over the anal opening, or the anal canal that links the rectum with the anus has not developed. The rectal pouch may be connected to the vagina, urethra, or bladder, and a baby with this problem will need immediate surgery. This condition is rare, but every baby is carefully checked at birth, so treatment can be given if necessary.
Umbilical hernia problems
In most babies, the gap in the muscle sheath in the abdominal cavity, where the umbilical cord entered his abdomen, normally closes up in time. Sometimes, though, a soft swelling called an umbilical hernia forms when the abdominal contents bulge through this weak spot in the abdomen. The hernia usually disappears eventually, although a few babies may need surgery later in childhood.
Congenital heart disease
Hole in the heart (ventricular septal defect) is the most common form of congenital heart disease. In this condition there's a hole in the baby's septum, the thin dividing wall between the right and left ventricles (pumping chambers) of the heart, so the ventricles are connected instead of being divided. A newborn baby doesn't usually show any signs of the problem. It may take as long as four weeks for the blood vessels in the lungs to relax sufficiently to allow pressure differences to develop between the ventricles and this means that there may not be much left-to-right shunt of blood through the hole for a month or so. Until then, there probably won't be any symptoms. Signs to look out for are a bluish tinge to the skin especially round the mouth, floppiness, and breathlessness. One of the first signs may be breathlessness while feeding. Not all babies need surgery; in some, the hole seals of its own accord.
Some types of congenital heart disease can be picked up by an ultrasound scan before birth. If your baby is found to have a serious heart problem, your doctors may advise you to give birth in a hospital that's equipped with special facilities for dealing with such conditions.
Congenital hip dysplasia
In this condition the ball at the head of the thighbone doesn't fit snugly into the socket of the hip joint. It ranges in severity from mild loosening to complete dislocation of the thighbone. In the newborn infant this is a potential, rather than an actual, problem. It's twice as common in girls and following breech births.
When your midwife does a routine check of your newborn baby, she'll check the hips for excessive mobility, or for a characteristic “clunk” felt when the baby's legs are spread apart and the thighs are flexed. If there's any doubt, she'll get specialist advice. Early follow-up and treatment such as manipulation and splinting may prevent trouble later, but some babies with severe dislocation need surgery.
Spina bifida problems
In this condition the vertebral bones of the spine do not fuse at some level in the spinal column and the meninges (the coverings of the brain and spinal cord) bulge through the gap. The area may be covered with skin or only by a bluish membrane, and may contain nerve roots, or the spinal cord itself may be exposed. In mild cases, the place where the vertebrae are not fused is covered with skin and is only marked by a small, dark, hairy mole. Happily, spina bifida is becoming less common. There's careful monitoring of those more at risk and we know much more about the importance of taking folic acid before conception and during the early weeks of pregnancy. As the various coverings that normally protect the cord aren't there, meningeal infection can happen easily, but can be prevented by immediate surgery to cover the defect. Spina bifida can be picked up by ultrasound and babies with a good prognosis can be sent to a special centre where surgery can be performed without delay. For babies with severe defects the outlook is not encouraging. Problems may include paralysis, incontinence, mental retardation, and hydrocephalus.
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