As the first Russian bombs fell on Ukraine, in vitro fertilization (IVF) and other reproductive health clinics across the country were forced to close, leaving the future of countless families hanging in the balance.
Now, when he walks through the doors of one of the largest IVF clinics in the country, he is virtually alone. While most of his employees have joined the more than 10 million Ukrainians who have fled their homes, he has decided to stay behind, working to coordinate the transportation of the nearly 19,000 embryos housed in his clinic.
"For this moment, few nurses, the cleaning lady and some technical staff are working, but most of our doctors and nurses went abroad," Zukin told TODAY Parents via phone. "Some of our doctors are in Sweden, Poland, Germany, France and some of them are in western Ukraine. So yes, very few people."
During peacetime, Zukin's clinic offered a variety of services — IVF, egg donation, sex selection, embryoscopy, embryo banking and artificial insemination, among others. In a single year, the clinic would facilitate over 1,000 individual IVF cycles.
Now, Zukin is focused on keeping the frozen embryos and eggs in his care viable; a profoundly difficult task as supply issues are making it difficult to obtain an adequate supply of liquid nitrogen.
"When people think about things being frozen, they usually think about food in their freezer or something like that. (For embryos), it's really a completely different process," Dr. Daniel Kenigsberg, a board certified reproductive endocrinologist with RMA Long Island IVF, told TODAY.
Kenigsberg explained that when you put something in a freezer, the frozen item is filled with water. Crystals form and while the item can be frozen for a short period of time, the item will begin to deteriorate over time as a result of its water content.
"When you freeze embryos or eggs, before they are frozen we have the water kind of leached out of them and replaced by something called cryoprotectant," he added. "So when you freeze an egg or an embryo, they don't have water in them and they are frozen in liquid nitrogen."
As long as the liquid nitrogen is replenished every week, embryos can stay frozen for years and even decades. If the liquid nitrogen runs out, however, the embryos will be destroyed.
"It would be almost immediate," Kenigsberg explained. "If the tank runs out of liquid nitrogen, that's it. It's a catastrophic event."
Back in Kyiv, Zukin has been able to successfully transfer 1,000 embryos to safety — some in western Ukraine, others out of the country. Zukin had to choose which embryos to send based on which ones were fresh and which patients would be able to continue treatment elsewhere.
"It was a very difficult choice for me," he said. "I went three days without sleep."
Zukin is also paying out of pocket for additional liquid nitrogen and electricity to the clinic to keep the remaining embryos viable. "I would like to support life," he explained. "Economics are a minimum barrier."
Zukin has been mostly unable to stay in contact with the patients of the clinic — some are staying in bomb shelters, while others have fled the country. He does not know how the abrupt end of any reproductive and fertility treatment they may have been undergoing has impacted them physically, mentally or emotionally.
"If somebody is doing a fresh IVF cycle, they go through about 10 to 14 days of ovarian stimulation," Kenigsberg explained. "When a person doesn't complete that (cycle) by having their eggs removed, there is some medical risk of the ovaries getting what's called hyper-stimulated."
When ovaries are hyper-stimulated, they swell and fluid used to stimulate the ovaries can leak into the stomach and other areas of the body, causing swelling, pain, nausea, vomiting and increased thirst, according to the Cleveland Clinic.
"There's also time lost, which is always a factor with fertility because as women get older their chances (of getting pregnant) get lower," Kenigsberg added. "So there's a certain time factor, and there's certainly a tremendous emotional factor, because it takes a great deal of emotional energy to prepare oneself for this — to have to stop it for whatever reason is devastating."
In addition to necessary medical supplies, reliable electricity and designated humanitarian corridors to safely transfer embryos out of Kyiv, Zukin believes that what clinicians, his patients and Ukrainians need most is the United States and other NATO countries to intervene and the war to end.
“I would like to ask the United States for military and political support,” he pleaded. “I think the world must stop being afraid of Putin, because it is a problem not only for Ukraine. The Ukrainian people defend not only Ukraine — they defend all civilization.”
The United States has sent billions of dollars worth of military and humanitarian assistance to Ukraine, but President Joe Biden has said on numerous occasions that he has no intention of sending U.S. military members into the country. And despite multiple requests from Ukrainian President Volodymyr Zelenskyy, the U.S. and its NATO allies will not enforce a no-fly zone that would require pilots from NATO countries to engage with Russian flyers.
As for Zukin, he says he has no intention of leaving Kyiv and will remain in his clinic, continuing to coordinate embryo transfers and work to keep those in his care from being destroyed.
"In a difficult time, you must be with your motherland," he said. "I feel that it is in my code — my dignity."