The development and adoption of real-time ultrasound was a revolutionary achievement. Ultrasound-guided amniocentesis was first described in 1972, 14 years after Ian Donald’s seminal paper introducing obstetric ultrasound was published in the Lancet (1958 Jun 7;1[7032]:1188-95).
As real-time ultrasound made its way into practice, it marked the true realization of a moonshot for obstetrics.
Not only could we simultaneously visualize the needle tip and place the needle safety, but we could see the real-time movement of the fetus, its activity, and the surrounding pockets of fluid. It was like looking up into the sky and seeing the stars for the first time. We could see fetal arrhythmia – not only hear it. With this window into the fetal compartment, we could visualize the fetal bowel migrating into the chest cavity due to a hole (hernia) in the diaphragm. We could visualize other malformations as well.
Chorionic villus sampling (CVS) was technically more difficult and took longer to evolve. For years, through the early 1980s, it was performed only at select centers throughout the country. Patients traveled for the procedure and faced relatively significant risks of complications.
By the end of the 1980s, however, with successive improvements in equipment and technique (including development of a transabdominal approach in addition to transvaginal) the procedure was deemed safe, effective, and acceptable for routine use. Fetoscopy, pioneered by John Hobbins, MD, and his colleagues at Yale University, New Haven, Conn., had also advanced and was being used to diagnose sickle cell anemia, Tay-Sachs disease, congenital fetal skin diseases, and other disorders.
With these advances and with our newfound ability to obtain and analyze a tissue sample earlier in pregnancy – even before a woman shared the news of her pregnancy, in some cases – it seemed that we had achieved our goals and may have even reached past the moon.
Yet there were other moonshots being pursued, including initiatives to make prenatal diagnosis less invasive. The discovery in 1997 of cell-free fetal DNA in maternal plasma and serum, for instance, was a pivotal development that opened the door for noninvasive prenatal testing.
This, and other advances in areas from biochemistry to ultrasound to genomic analysis, led to an array of prenatal diagnostic tools that today enable women and their physicians to assess the genetic, chromosomal, and biophysical aspects of their fetus considerably before the time of viability, and from both the maternal side and directly in the fetal compartment.
First-trimester screening is a current option, and we now have the ability to more selectively perform amniocentesis and CVS based on probability testing, and not solely on maternal age. Ultrasound technology now encompasses color Doppler, 3D and 4D imaging, and other techniques that can be used to assess the placenta, various structures inside the brain, and the heart, as well as blood flow through the ductus venosus.
Parents have called for and welcomed having the option of assessing the fetus in greater detail, and of having either assurance when anomalies are excluded or the opportunity to plan and make decisions when anomalies are detected.
Fetal surgery has been a natural extension of our unprecedented access to the fetus. Our ability to visualize malformations and their evolution led to animal studies that advanced our interest in arresting, correcting, or reversing fetal anomalies through in-utero interventions. In 1981, surgeons performed the first human open fetal surgery to correct congenital hydronephrosis.
Today, we can employ endoscopic laser ablation or laser coagulation to treat severe twin-to-twin syndrome, for instance, as well as other surgical techniques to repair defects such as congenital diaphragmatic hernia, lower urinary tract obstruction, and myelomeningocele. Such advances were unimaginable decades ago.
Old foes and new threats
Despite these advances in diagnosis and care, obstetrics faces unrealized moonshots – lingering challenges that, 50 years ago, we would have predicted would have been solved. Who would have thought that we would still have as high an infant mortality rate as we do, and that we would not be further along in solving the problem of prematurity? Our progress has been only incremental.
Fifty years ago, we lacked an understanding of the basic biology of preterm labor. Prematurity was viewed simply as term labor occurring too early, and many efforts were made over the years to halt the premature labor process through the use of various drugs and other therapeutics, with variable and minimally impactful levels of success.
In the last 25 years, and especially in the last decade, we have made greater efforts to better understand the biology of premature labor – to elucidate how and why it occurs – and we have come to understand that premature labor is very different physiologically from term labor.