For days after the order was signed, international airports became sites of confusion and protests, with travelers' legal status suddenly thrown into question.
Meanwhile, Shamshirsaz, a maternal-fetal medicine specialist, wondered how the order might apply to him. He is a green card holder who had "zero problems" traveling back and forth between Iran and Texas before the executive order was signed. Nobody had ever questioned why an Iranian doctor, often in the company of other medical professionals, needed to travel between countries.
After the executive order, "I talked to different lawyers, and nobody had any kind of clear-cut answers to me as to what would happen," Shamshirsaz said.
After days of fraught discussions, he canceled his trip to Iran "because of all these uncertainties."
At the time, making the decision seemed like the painful part. But then Shamshirsaz contacted the families via Skype and witnessed their emotional reaction.
"It was really heartbreaking. It was very tough for me to personally talk with the families and say, 'sorry, I cannot make that trip,' " he said.
The surgeries he and his team routinely perform, both in the United States and internationally, are interventions to treat "lethal conditions" in developing fetuses, he said. Some are minimally invasive "ultrasound guided" operations in which surgeons make small incisions and use instruments inside the womb. Others are highly invasive "complex (surgeries) where you need to open the uterus and expose the site that needs surgery and then close the uterus," Shamshirsaz said.
"Because I couldn't go and do the surgeries, then definitely, we will lose those babies," he said. "There was no other option for those families."
Like father, like son
"I followed in my dad's footsteps," said Shamshirsaz, affectionately known as "Dr. Shami" by patients and staffers at Texas Children's Hospital, where he practices medicine and surgery, and at the Baylor College of Medicine, where he is an assistant professor.
"My true background is obstetrician and gynecology," he said, just like his father, who trained at Yale in the 1970s, then returned to Iran and became a prominent ob/gyn who maintains a thriving practice in Tehran.
"That was my role model for my life," said Shamshirsaz, who received his medical degree at Tehran University Medical School and then completed residencies and fellowships at the University of Iowa and the University of Connecticut.
While learning fetal medicine, Shamshirsaz found himself increasingly interested in high-risk pregnancies, so after he completed his training, he enrolled in Baylor's perinatal surgery program.
"It's a very hard life, but it's rewarding," he said. "It's hard because first of all, you have no schedule of your life. Babies can come anytime, and these babies are so sick that you cannot wait. At the same time, you are doing a surgery on a very, very small human."
Some of the babies he operates on are just 16 or 17 weeks in utero and "are very teeny, meaning 100 to 200 grams" -- not even half a pound.
In 2014, Shamshirsaz completed his two-year program at Baylor and signed a contract with Texas Children's Hospital that allowed him to divide his time: 75% employment at the hospital and 25% free time to work in Iran.
"One of my goals when I came here, I mentioned to Texas Children's Hospital, when I finished my scholarship, my training, I wanted to devote some of my time back home, and they were very supportive," Shamshirsaz said.
"In going back to Iran, the plan was starting the fetal center at the beginning and then start training a new generation of people as fetal surgeons," he said.
Training surgeons around the world
The first part of his ambitious plan is well underway. Shamshirsaz has been going back every couple of months, staying for two to three weeks at a time in order to see patients and perform two or three fetal surgeries.
"I can count to about 30 successful surgeries so far I have performed there," he said.
"Nobody pays me, and I even pay my own tickets to go back home," he added. "We are working as a charity. We do the surgeries, and we come back to Houston."
The second part of his plan, the training of new surgeons, has just begun. Right now, nobody in Iran has the skill or training to perform these surgeries.
"We are training two people in Tehran University and two people in Shiraz University," Shamshirsaz said. "This will take about three to four years of training, but the plan is that once those people are trained, then they can independently do this type of fetal surgery and they can go on.
"Fetal intervention surgery is a new entity, a new subspeciality, and I think it is my job to train a new generation not only in the US as we are doing now ... but also train other people and other physicians around the world," he said.
According to Dr. Mike Vlastos, a SLUCare maternal fetal medicine specialist and director of the SSM Health St. Louis Fetal Care Institute, which specializes in fetal diagnosis and surgery, there are only about 15 centers in the US that have done one or more open-womb fetal surgeries and about 30 centers that provide minimally invasive fetal procedures. Though multiple people at each institution can provide these services, fetal surgery is still a small field since its inception in the 1980s.
Shamshirsaz "is kind of a remarkable person from the aspect of traveling to the West and then going back to his country to really set up and commence a fetal program," said Vlastos.
Shamshirsaz does not want to limit his charitable work to Iran, still he admits he is most "efficient" in his home country, where he has connections and knows the people, the language and the culture.
"I did have a trip last year to Malawi, one of the African countries, and I stayed there for a month with my brother, and we tried to set up some kind of critical-care ob/gyn for that country."
His younger brother is also a physician at Texas Children's Hospital, as is his wife. "The majority of my family are in the US," Shamshirsaz said.
With the travel freedom he's had, he said, "you can take the knowledge and skills that you have learned in the US, and you can take it and try to spread it outside of the US."
Currently, the travel ban is not being enforced. A ruling from federal Judge James Robart in Seattle on February 3 blocked the ban nationwide.
The Trump administration appealed, and a three-judge panel issued a unanimous ruling that maintained the block. Citizens of the seven majority-Muslim countries will be able to travel to the US despite the executive order.
Still, Trump has indicated that he may continue to fight the case in courts or sign a new executive order.
When the order was initially issued, friends, mentors and colleagues at Texas Children's expressed their sympathy to Shamshirsaz.
"I get lots of emails and calls from my friends to say they are unhappy with the situation" of mixing science and medicine -- helping people -- with politics, he said.
Shamshirsaz said he hopes that by the time his next trip to Iran comes around, "we will be more clear about what's going on. The next trip will be in May. It's already scheduled."