Since we have been on the subject of aneuploidy screening, let me tell you about a situation that we had on Friday that epitomizes the importance of knowing as much as you can about a baby, including its karyotype (chromosomal status), before delivery….
Our patient is an 18 year old, having her first baby, who was a late entry to prenatal care at an outlying clinic. She was seen by one of my associates for a routine ultrasound to confirm gestational age and assess fetal anatomy. At that visit, she was estimated to be about 27 weeks’ pregnant but, unfortunately, the baby was found to have a congenital diaphragmatic hernia. She had come alone to that visit and, when told of the findings, she apparently became too upset to benefit from any attempt at counseling at that time. Arrangements were made for her to see me for a ‘second opinion’ and also to see our genetic counselor a few days later.
My findings confirmed the initial diagnosis. The baby had a large diaphragmatic hernia, with stomach and bowel filling the entire left chest, pushing the mediastinum and heart to the right chest wall. Very little lung tissue could be seen above the heart. The baby had a single (rather than the normal two) umbilical artery, an absent right kidney, generalized soft tissue edema (fluid accumulation), and polyhydramnios (increased amniotic fluid). The baby was also growth restricted. I expressed my concerns that the baby’s prognosis was poor because of the size of the defect and the paucity of normal lung tissue and also because the baby had a greater likelihood of having a chromosomal problem in view of the multiplicity of the abnormalities seen. She was encouraged to undergo an amniocentesis to determine the fetal karyotype and told that this would help to guide our counseling about recommendations for delivery, and the decisions that would have to be made with her regarding resuscitative efforts following the birth of the baby. She was not at all enthusiastic about having a long needle placed in her abdomen, but when she asked me if I had ever done one (an amniocentesis) before, I told her “No, but I did stay at a Holiday Inn Express last night” and, when she laughed, despite the gravity of the situation, I knew we had made some real progress in her care.
Ten days later, the baby’s karyotype returned abnormal with “mosaicism for an isochromosome of 12p.” To translate that into understandable terms, this means that in certain cells (not all) in the baby’s body, there are 4 copies of the short arm of chromosome 12 rather than the normal two. The abnormalities seen by ultrasound, coupled with the fetal karyotype, made it highly likely the baby had a condition called Pallister-Killian Mosaic Syndrome. This is a very rare chromosomal disorder that occurs sporadically, for no apparent reason, and is not likely to recur.
The patient returned for another ultrasound after the karyotype results were obtained. The ultrasound revealed worsening polyhydramnios (a further increase in amniotic fluid), progressive fetal growth restriction, and abnormal Doppler flow studies suggesting fetal blood flow redistribution, or ‘cranial sparing,’ a physiologic event that often accompanies placental insufficiency that helps to preserve the baby’s brain at the expense of temporarily underperfusing less essential organs. She was told in view of these findings that there was now an increased likelihood of delivery sooner than later, either because of preterm labor, spontaneous rupture of membranes, fetal decompensation, or preeclampsia that might develop as a consequence of the fetal compromise. She spent some more time with the genetic counselor that day and then told us that she thought she would not want heroic measures taken for the baby at delivery. We set up consultations for her with Pediatric Surgery and the Neonatalogists.
Not three days after this visit, and at about 31 weeks,’ she presented to our labor and delivery unit in active labor with spontaneous rupture of membranes. We reviewed the baby’s findings with her again, the prognosis, and her options for care of the baby after delivery. She was told that if she wanted to do everything that was medically possible, we still had time to send her to an institution that had ECMO (extracorporeal membrane oxygenation); although we could not guarantee that the baby would even be a candidate for it. She actually smiled and thanked us but said, “No, we just want to be able to spend as much time with the baby as we can after she’s born.” She and her whole family were at peace with the decision. At that point, we disconnected the fetal heart rate monitor, arranged for placement of epidural anesthesia, and contacted the NICU staff.
Early that evening, she delivered, vaginally. The baby was barely alive at birth but was pink, had her blue eyes open and a slow heart beat. Thankfully, the baby made no effort to breathe or cry and, with respect for the expressed wishes, no effort was made to ‘resuscitate’ her. We dried the baby off, swaddled her in a warm blanket, and handed her to the young mother to hold. At first, she could not look at the baby, but when her mother-in-law offered to take the baby from her, she wiped off the tears streaming down her face, pulled the blanket down to expose the baby’s face, smiled, and stated that “She looks just like her Daddy,” and then gently sought out and touched the baby’s tiny hands and feet. After a few minutes, she finally shared the baby with the grandparents, her sister, and other family members who had been there to support her throughout the day. As the baby’s color darkened and the heart beat slowed further, her eyes closed, and one of the grandparents held her in the air, looked up, and said, “Tell all the grandmas and grandpas up there that we love them, too,” (and let me tell you, when she did that, there wasn’t a dry eye in the room) and handed the baby back to her mother, on whose chest she finally succumbed.
I probably don’t need to tell you (and that’s the real reason for this post) that this touching scenario could easily have been much different if we had not had the knowledge of this baby’s physical and chromosomal abnormalities, and the opportunity to discuss the findings and prognosis with the patient before the delivery. In the end, this young mother was able to make the right decision for herself and she got to spend a few precious moments with her baby while she was still alive. She thanked me as we left the room for “everything we had done for her,” and I could only nod my head and think to myself that I should be thanking her for everything she did for us….