TORONTO -- Seven or eight years ago, Dr. Harvey Kliman saw a number of pregnant patients in a row who lost their fetuses around the 25-week mark, and they all shared one common feature.
The placenta, which supplies nourishment in utero, was "extremely small."
"If the placenta is too small the fetus will be small, but if it is really small, then the fetus can just die," said Kliman, a research scientist in the department of Obstetrics, Gynecology and Reproductive Sciences at Yale University. "It's really like running out of gas in a car."
He began asking his colleagues why they don't routinely follow the placenta.
"They said it's just too difficult to do. It's a curved structure. It looks something like a beanie cap, basically. And there's no simple way to do it."
The best approach is taking three-dimensional ultrasound measurements, which requires specialized training. So Kliman talked to his father, Merwin Kliman, an engineer and mathematician, about the possibility of coming up with an equation to calculate placental volumes using widely accessible two-dimensional ultrasound measurements.
A study published in the American Journal of Perinatology is a first step toward validating the equation. Thirty-eight patients consented to take part, but nine placentas could not be evaluated properly.
Kliman's team at Yale compared the volume predicted by the Estimated Placenta Volume equation taken just before delivery by the remaining 29 women in the study to the actual weight of the placenta at the time of delivery. The equation predicted the actual placental weight with an accuracy of up to 89%, they discovered.
Dr. John Kingdom, maternal fetal medicine specialist at Mount Sinai Hospital in Toronto, said he commends the authors for being interested in the area because there's no doubt there's an association between small, damaged placentas and adverse outcomes.
"But it would be dangerous and wrong to suggest that women should then seek a placental scan for no reason other than that they're worried ... we do have a responsibility to do the right research and place it in its right context," said Kingdom, who heads the hospital's placenta clinic with Dr. Rory Windrim.
Kliman sees the Estimated Placental Volume being calculated at 18 weeks or 20 weeks, the normal time that routine scans are done.
