Dr. Kevin Worley, one of
maternal-fetal medicine experts, about 3 percent of all births have some type of birth defect,
which makes them fairly common when you take them in aggregate.
Worley says cardiac defects are No. 1, followed by neural tube defects,
which are full-thickness defects that expose the brain or spinal cord
elements. Neural tube defects happen in the first month of pregnancy,
often before a woman even knows that she is pregnant. The two most common
neural tube defects are spina bifida and anencephaly (a skull bone not
formed). In spina bifida, the fetal spinal column doesn’t close
The statistics show cardiac defects in about 8/1000 live births; neural
tube in about 1-2/1000 live births. Other types of organ systems malformations
occur with less frequency.
Preventable or not?
“Certainly not all birth defects are preventable, and we don’t
know what causes some of them,” Dr. Worley said. “But some
are. There are some that are affected by genetic conditions, medical complications,
environmental situations, micro-nutrient deficiencies, and other things.”
Dr. Worley said these are the best things to focus on for optimum prevention:
- All women of childbearing age should take 400 mcg of folate (folic acid).
That’s been shown conclusively to help prevent neural tube defects
and may also help prevent some cardiac defects as well.
- If a woman has chronic medical conditions like diabetes, seizure disorders,
autoimmune conditions (just to mention a few), preconceptional counseling
is very important so that she can help optimize her medical condition,
which can help decrease birth defects.
- Also, medications that are used to treat some of those medical conditions
need to be evaluated, because there are some medications themselves that
can induce birth defects. So we might pick a different medication for
a woman trying to conceive. Numerous medications have been implicated
in birth defects, for example some blood thinners, anticonvulsants, and
chemotherapy drugs are strongly associated with birth defects. It really
just depends on the medical condition that’s being treated. It’s
best to sit down with your physician and evaluate all the medications
the woman is taking.
“There are some antibiotics we try to avoid in early pregnancy. But
the majority of them are considered safe,” Dr. Worley said. “But
that’s why it’s important to consult with your OBGYN or maternal-fetal
medicine specialist, when you’re selecting medications to use in
pregnant women, particularly in the first trimester when the organ systems
Regarding folic acid, Dr. Worley says it can be purchased over the counter.
“Grains are now fortified with folate, but we have seen that the
vast majority of women do not get a sufficient amount of folate from their
everyday diet alone. Any woman of childbearing age really should focus
on taking 400 mcg daily. Most multivitamins, and certainly most prenatal
vitamins contain that quantity.”
Dr. Worley stressed that any woman who is attempting conception or may
become pregnant, should abstain from alcohol and stop smoking.
“If you have an occupational exposure where you’re around certain
toxins or chemicals, perhaps its best to avoid those things,” he
said. “Obesity has consistently and conclusively been proven to
increase rates of birth defects, so weight loss, if appropriate might
be something to focus on before attempting conception.”
As far as prevention, Dr. Worley says so much of it revolves around focusing
on a healthy lifestyle and maximizing healthy benefits and healthy habits.
Avoiding things like cigarettes, alcohol, illicit drug use; exercise and
weight loss are important.
Are there signs or symptoms? What about genetics?
Most birth defects are usually seen in routine ultrasound exams.
“The majority of women now have ultrasounds in pregnancy, and we
do screen for malformations every time we do an ultrasound, particularly
around mid-pregnancy,” Dr. Worley said. “We do what we call
the ‘anatomy exam,’ where we look as carefully as we can at
the organ systems to detect malformations. But an ultrasound is not going
to detect all birth defects or all malformations. For instance, some types
of intestinal obstructions won’t generally be picked up on an ultrasound.
A very small hole in the heart, especially an atrial septal defect, will
perhaps not be detected by prenatal ultrasound.”
Amniocentesis will detect chromosomal abnormalities like Down Syndrome,
and now even single gene disorders, like sickle cell disease and cystic
fibrosis can be screened for with amniotic fluid.
There are numerous and varied types of genetic conditions that can affect
a pregnancy. Problems with an abnormal number of chromosomes (termed “aneuploidy”),
like Down Syndrome, tend to be the focus of routine prenatal screening.
However, aneuploidy only represents a portion of the genetic conditions
that can cause birth defects or disability after birth. Consultation with
a maternal-fetal medicine expert is appropriate for any woman who is at
increased risk for genetic conditions or birth defects or is found to
have a birth defect while they’re pregnant.”
Dr. Worley says if you have a baby who has a birth defect, it is important
to not only be in consultation with your OBGYN, but also with a maternal-fetal
specialist who can help fully evaluate the condition, help make the diagnosis
and help coordinate not only the obstetric care, but the pediatric care
“There is a lot of great information on the web,
the CDC website has a lot of very plain-English information about what birth defects are,
which ones are common and how they can be prevented, to the extent that
they can be prevented.”