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Understanding Birth Defects, Risks, and Screening and Prevention Options

pregnant belly

Whether a woman is expecting her first baby or has welcomed multiple children into the world, her pregnancy involves many considerations, from the light — such as picking a name and plotting out the perfect nursery — to the serious — such as getting recommended care and screening for birth defects. “Even with something that isn’t life-threatening, early intervention during pregnancy helps improve outcomes for babies and mothers,” explains Holly Casele, MD, chief of San Diego Perinatal Center, the maternal-fetal medicine division of Rady Children’s Specialists of San Diego. Given the fact that a baby in the United States is born with some form of birth defect every four-and-half-minutes — working out to about 120,000 per year or one in every 33 births[1] — early-stage and ongoing prenatal care can have significant, positive effects on a very common set of health conditions.

The range of defects is vast, and include those linked to infections or toxin exposures during pregnancy, such as fetal alcohol spectrum disorders; those linked to genetic mutations, such as cystic fibrosis, sickle cell disease or Fragile X; those linked to abnormal chromosomes, such as Down syndrome; and those affecting structure without ties to specific genetic or chromosomal cause[2], [3]. However, says Dr. Casele, the term “birth defect” can be open to medical interpretation. “Clearly, a complex heart defect that requires open heart surgery after birth would be considered a birth defect. But what about a small muscular ventricular septal defect, or ‘hole in the heart,’ that is expected to close on its own and have no impact on the baby’s health? Although this type of defect can occur in otherwise typical babies, it also occurs in babies with Down syndrome or certain genetic syndromes. Therefore, interpreting the significance of certain findings requires careful consideration of the entire clinical picture: the patient’s personal history, testing and risk factors.”

While not all forms of defects are preventable, there are a number of simple and important actions moms-to-be can take to help reduce their baby’s risk. A major one: “Avoid teratogens — products that can harm a developing fetus with exposure — like alcohol, tobacco, illicit substances, and even many ‘everyday’ medications plays a key role in prevention,” says Dr. Casele. “Talk to your physician about your medications, supplements and personal care products to ensure they are safe for your baby before you get pregnant. Eliminate mercury-containing fish, raw meat products and unpasteurized dairy products.” Women can also work to cut down on their risk for infections through steps such as avoiding handling dirty cat litter; discussing recommended vaccines with health care providers; getting screened for sexually transmitted infections and group B strep; and using effective handwashing practices, especially after using the bathroom, interacting with pets or children, touching unwashed produce or raw meat or eggs, or gardening. Zika virus also remains an infection risk, so avoid traveling to areas in which Zika is common as much as possible[4]. In addition, studies have indicated that elevated body temperature during the first trimester may increase risk for birth defects. As such, Dr. Casele advises pregnant women to not raise their core body temperature beyond 101 F, meaning “steer clear of hot tubs, and no hot yoga.” She also emphasizes taking a supplement of 400 micrograms of folic acid each day at least a month before and throughout pregnancy to help protect against spina bifida and neural tube defects such as anencephaly.

Because having children later in life has become increasingly common, many women may worry about the additional risk that correlates with having a baby at “advanced maternal age,” which, medically speaking, is considered 35 years and above. “The chance of a having a baby with a chromosomal abnormality does rise with a mother’s age, and therefore, it is important for women to have an informed conversation with their doctor about their own unique risk factors and what screening and testing options are right for them,” explains Dr. Casele. “Diagnostic tests such as amniocentesis and chorionic villus sampling provide the most information, but have risk because they are invasive. Noninvasive screening blood tests do not have risk, but provide more limited information. Consideration of a patient’s unique history, risks and desires for her pregnancy are essential to navigate the complexity of the testing and screening options.

Although carrier testing is available for more than 500 genetic conditions, the American College of Obstetricians and Gynecologists currently endorses screening for the three most common: cystic fibrosis, Fragile X and spinal muscular atrophy. While screening for hundreds of conditions may seem great, with each condition checked, there is an increased likelihood of coming up as a carrier for something — and that doesn’t necessarily mean you will pass on that condition to your baby. At that point, it would be advised that your partner get screened as well, and sometimes more testing just raises more questions. It can be very stressful for parents, so education and in-depth conversations with your doctor are central to managing expectations and identifying true areas of concern.”

Should a screening find that a baby has or is more likely to have a birth defect, Dr. Casele advises that the mom-to-be first visit a perinatologist, or a maternal-fetal medicine physician who focuses on high-risk pregnancy care. The perinatologist can then explain the findings in-depth and work to determine appropriate next steps, such as exploring additional testing, genetic counseling or connecting with a pediatric specialist to put a care plan in place for when the baby is born and understand long-term prognosis.

Dr. Casele also highlights the importance of cervical length screening, a recommended procedure for all pregnant women between 16 and 26 weeks gestation. “A short cervix in the second trimester is associated with a greater risk for preterm birth,” she notes. “Preterm birth is one of the highest contributors to infant morbidity and mortality in the United States. Identifying patients at risk for preterm delivery can facilitate earlier detection and treatment of preterm labor.”

While the precautions, choices and appointments involved with pregnancy can be daunting, a strong care team can make a world of difference. “Early and consistent prenatal care enables patients to make informed choices about their pregnancies and their providers to identify potential risk factors and devise care plans to keep both mom and baby as safe and healthy as possible. That’s always our number-one focus,” says Dr. Casele.