Genetics is one of the fastest growing subspecialties in medicine but has only recently been applied in the field of obstetrics, where it is complicated because there are three humans involved – the woman, the father of the baby, and the unborn child. Women & Infants' Division of Maternal-Fetal Medicine offers a Reproductive Genetics Service, one of the few of its kind in the nation with multiple physicians on staff with advanced training in both maternal-fetal medicine and clinical genetics. Here, Dr. Katharine Wenstrom, director, explains the field and how it can help couples planning to have a child or women who are already pregnant.
What is reproductive genetics? How is that a natural extension of maternal-fetal medicine?
Reproductive genetics is an area of genetics that focuses on issues intimately tied to a woman's family and her own reproductive life. These issues include genetic factors that increase the risk of an adverse pregnancy outcome, male and female infertility, and a family history of genetic abnormalities. In such cases, reproductive geneticists often provide preconception counseling and advice on how the couple might improve the outcome of any future pregnancies . We also see pregnant women whose advanced age increases the risk of chromosomal abnormalities who have fetal abnormalities discovered, or who are exposed to harmful environmental agents.
Reproductive genetics is a natural extension of maternal-fetal medicine in that both fields address maternal and fetal complications during pregnancy. Both fields also offer prenatal diagnostic testing such as chorionic villus sampling and amniocentesis in order to diagnose genetic conditions.
Who is your typical patient – women with conditions that may be aggravated by pregnancy or women who are already pregnant and have testing that reveals something abnormal with their unborn baby? Or both?
My typical patient is a woman who is pregnant and has either a known genetic condition or a family history of a genetic condition. She comes in because she wants to discuss the risks for her fetus and possibly undergo fetal testing. In addition, I often see women who have had an abnormal prenatal ultrasound and/or whose fetus has an abnormal chromosomal or genetic syndrome.
What are some of the reasons a woman might visit the Reproductive Genetics Service?
There are many reasons a woman might visit the Reproductive Genetics Service. Perhaps she or one or more of her family members may have a genetic disorder that has implications for her future baby and she wants counseling and evaluation. Some women choose to come in for a diagnostic test such as a chorionic villus sampling or a genetic amniocentesis to evaluate the fetus' chromosomal or genetic status. Women may seek our services to discuss potential fetal exposures to medications, infections or other environmental agents. Abnormal ultrasound findings or abnormal serum screening results (such as an abnormal Down Syndrome screening test) are other common reasons for referrals.
Some of your work involves men, does it not?
Yes. I work with men who have been diagnosed with a genetic condition or a family history of a genetic condition. Some of these genetic conditions can be transmitted to a man's offspring, so I counsel men about their fetus' risk of inheriting their disorder. I also see men who are infertile due to genetic causes.
Do you ever work with a baby after birth?
I work closely with the pediatric geneticists, cytogeneticist and metabolic geneticist on campus. We have multi-disciplinary meetings before a baby is born to discuss the case in a confidential manner, review the diagnosis, and prepare the neonatologists for the baby's arrival.
Sometimes, women face the difficult decision of taking medication for a medical condition and wondering if it is having some effect on their fetus. Can you help with that?
Absolutely. I am trained in teratology (the study of abnormalities in physiological development) and often counsel women on the risks/benefits of taking medications during pregnancy. Being a maternal-fetal medicine specialist as well as a geneticist is helpful in that I know the importance of certain medications in treating the maternal condition.
Besides your training, what tools do you use?
One of the most helpful tools and biggest assets to the Reproductive Genetics Service are the genetic counselors. We have seven board-certified genetic counselors who see a variety of patients for multiple reasons. Another tool I use is the Level II ultrasound exam for the detection of structural abnormalities. For diagnostic testing, I rely on chorionic villus sampling and amniocentesis. Genetic counseling and various clinical examinations are available at the hospital's Prenatal Diagnosis Center.
I also use my other "genetic colleague," Dr. Katharine Wenstrom, who is also board-certified in genetics and maternal-fetal medicine and director of the Division of Maternal-Fetal Medicine at Women & Infants.
One of your specialties is prenatal management of twin pregnancies. What makes a twin pregnancy different from a single pregnancy?
Twin pregnancies are medically more complicated than singleton pregnancies and generally have a higher incidence of maternal and fetal complications. Some of the maternal complications most commonly seen in twin pregnancies are diabetes, preterm labor and delivery, preeclampsia, bleeding, and a higher rate if cesarean delivery. Fetal complications such as birth defects and growth problems are more likely with identical than fraternal twins.
You recently published the results of a study that indicate the importance of determining the point of conception in twin pregnancies. Why is that so important?
The management of many of the problems that occur in twin pregnancies depends on knowing the precise gestational age. For example, we can only determine if fetal growth is normal if we know exactly how advanced the pregnancy is. Gestational age is also important for determining the best management of preterm labor and for the timing of elective delivery.
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