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Prenatal Diagnosis

Prenatal Diagnosis 2017-11-30T23:53:53+00:00

Can cleft lip, cleft palate, and other facial differences be detected before a child is born?

Sometimes, yes. Using a technique known as high-resolution ultrasonography, doctors can obtain a detailed, two-dimensional image of a developing fetus. The image, known as a sonogram, can usually reveal whether there is a cleft lip or other major abnormality of the face or head.

Cleft palate cannot reliably be detected prenatally. Three-dimensional ultrasonography and prenatal magnetic resonance imaging (MRI) are available in some centers and may aid in the diagnosis of cleft lip and palate.

Doctors can often determine whether a fetus is at risk for certain inherited chromosomal disorders by performing tests known as amniocentesis and chorionic villus sampling. In these tests, under ultrasonic guidance a doctor uses a thin needle to remove fetal cells from the amniotic fluid or the tissues surrounding an early embryo. The cells are grown and analyzed through a microscope to see if the chromosomes, which carry genetic information, have any abnormalities. Doctors are able to link specific chromosomal abnormalities to an increased risk for certain types of craniofacial conditions.

At what stage of pregnancy does cleft lip and palate become visible by ultrasonography?

Facial features such as the nose, lip, and part of the hard palate are formed by the fourth to sixth week of pregnancy. Generally, however, these features are not visible until the mid-second trimester of pregnancy, at about 16 to 18 weeks. Though transvaginal sonography can sometimes detect cleft lip at an earlier gestational age (10–12 weeks), most babies with cleft lip are diagnosed during a routine fetal survey at approximately 18 weeks gestation.

In most centers, the sonologist (a physician specializing in ultrasonography) will either perform the sonogram or interpret the images obtained by a sonographer (a technologist specially trained in ultrasound). Sometimes fetal magnetic resonance imaging (MRI) will also be used, which can yield additional information. The radiologist will discuss the results of your sonogram with you or the physicians on your child’s care team. Team members will talk with you about what to expect, how to feed your baby, and about a plan for repairing the cleft.

At what stage of pregnancy do other types of facial and head differences become visible by ultrasonography?

This varies for different conditions. In general, a second-trimester sonogram can show whether the baby has a normally shaped skull and can suggest whether the bones of the skull have fused prematurely (craniosynostosis). At the same stage of pregnancy, ultrasonography can often help doctors diagnose hemifacial microsomia, in which parts of a child’s head are smaller than expected.

Can facial differences always be diagnosed before birth?

No. Subtle differences in facial structures may not be visible with prenatal ultrasonography. Many anomalies cannot be detected until after the baby is born.

When will a doctor order an analysis of a fetus’s chromosomes?

Chromosomal analysis is generally recommended when a second-trimester sonogram shows a problem in a developing fetus. This is especially true if there is a family history of a genetic disorder or syndrome. In addition, many women are offered the option of chromosomal analysis if they are over 35 years of age when they become pregnant.

Preparing Yourself for the Best Possible Start

When you receive a prenatal diagnosis that your child may have a craniofacial condition, there are several steps you can take to prepare yourselves for parenthood and to give your baby the best possible start in life.

First, be aware that prenatal diagnosis is not exact and it is not always possible to predict what problems, if any, your child will have. When a diagnosis of a craniofacial condition is made, it is important to seek out a craniofacial team so you’ll be prepared when the baby arrives. Prenatal interdisciplinary care teams are also available in some large children’s hospitals.

Gather as much information about your child’s expected condition as you can. By learning the medical terms, you’ll be better able to communicate with members of your child’s team. Remember that parents learn at different paces, so be patient with each other. It is natural to wonder about your baby’s appearance and social and intellectual capabilities. Learn what you can.

Many expectant parents decide to share news of their child’s situation with close friends and family members. The support of others can be invaluable. Always remember that the coming birth is a joyous event, as much now as before the diagnosis, and that you are learning more about your soon-to-arrive baby.

As the delivery date approaches, discuss the diagnosis and birthing options with your obstetrician and staff. Make sure the delivery room is notified in advance. Also find out what procedure the hospital follows in the case of a nonstandard birth. In some birthing centers, babies with problems are immediately taken to an evaluation area; in others, once the medical staff is sure the baby can breathe properly, the parents and their new baby may spend time together.

Because of the added challenge a baby with a craniofacial condition may present, it is a good idea to arrange for some help when the baby is brought home. That will make the transition to home life easier for you and your new baby.

Prenatal Diagnosis of Cleft Lip:
What the Sonologist Needs to Tell the Surgeon,”

John B. Mulliken, M.D., and Beryl R. Benacerraf, M.D.

Prenatal Sonographic Diagnosis of Major Craniofacial Abnormalities,”
Granger B. Wong, M.D., D.M.D., John B. Mulliken, M.D., Beryl R. Benacerraf, M.D.

Beyond Easy Answers: Prenatal Diagnosis and Counseling during Pregnancy,”
Ronald P. Strauss, D.M.D., Ph.D