Women in the United States who conceived through assisted reproductive technology were significantly more likely to spontaneously abort or deliver their babies preterm in the six months following Hurricane Katrina, compared with the same period before the natural disaster.
“Interestingly, this increase in preterm delivery and miscarriage was not associated with Hurricane Katrina sites. That is to say, the rates were not [significantly] different in directly affected counties, but they were different nationally,” Sangita K. Jindal, Ph.D. said.
Dr. Jindal looked at singleton live births conceived through assisted reproductive technology (ART) before and after the category 3 hurricane slammed the Gulf Coast on August 29, 2005.
“We had to double check our math, because we were shocked,” said Dr. Jindal, IVF Lab Director at Montefiore Medical Center in Hartsdale, N.Y. “The reported preterm delivery rate in the country is 10% to 12%. In this study, we found a preterm delivery rate of 19% ‑ much higher.”
She also compared pregnancy outcomes in five states with counties directly affected by Katrina (Texas, Louisiana, Mississippi, Alabama, and Florida) to outcomes at clinics elsewhere across the country. “There was an 19% preterm delivery rate around the country and a 22% preterm delivery rate in Hurricane Katrina regions,” Dr. Jindal said at the annual meeting of the American Society for Reproductive Medicine.
The preterm delivery and miscarriage rates in regions affected by the hurricane already were elevated. Although they increased, the differences were not statistically significant, she explained.
Nationwide, however, “there was definitely a measurable increase in spontaneous abortions compared to pre-Katrina,”
Dr. Jindal said. Compared to the ART cycles initiated before the hurricane, those started in the six months after Katrina hit were 87% more likely to end in a first trimester pregnancy loss and 63% more likely to be a miscarriage by 16 weeks.
So why did adverse outcomes rise significantly across the country? “I would suspect that nationally women suffered a trauma, and they imparted some sort of stress factor to the intrauterine environment, which impacted negatively and directly on the fetus,” she said.
More specific information on cortisol levels or epigenetic factors is outside the scope of the data of 104,724 ART cycles provided by the Society for Assisted Reproductive Technology.
Unlike previous researchers who have found more girls born after a natural disaster, Dr. Jindal found an equal birth rate of 49.5% for each gender.
In the future, Dr. Jindal would like to perform a state-by-state analysis. She also wants to assess pregnancy outcomes by maternal body mass index, because maternal weight “may be a confounding variable.”
–by Damian McNamara (on twitter @MedReporter)