Ilka Riddle of Newark was determined to give birth to a healthy baby when she found out she was pregnant for the first time.
She made it a point to eat fruits and vegetables and to exercise frequently.
Annika Riddle was born in April and weighed more than a pound less than average -- 6 pounds, 5 ounces.
"I thought she was light, and I thought she was a bit smaller -- but I didn't have anything to be concerned about," Riddle said. "I was actually happy that she wasn't big, because I was very nervous about having a big baby."
More mothers like Riddle are giving birth to newborns who are smaller than expected. From 1990 through 2005, the birthweights of newborns in the United States fell nearly 2 ounces to an average of 7 pounds, 7.54 ounces. In Delaware, the weight fell nearly 3 ounces to 7 pounds, 6.85 ounces.
Though researchers can't explain the trend, the decline is "alarming," said Dr. Jay Greenspan, a neonatologist and chair of the Department of Pediatrics at Alfred I. duPont Hospital for Children in Rockland. Over time, newborns should be getting heavier, he said, not lighter.
"It's a statement that the overall health of our pregnant mothers isn't as good as it used to be," he said. "We know that prematurity is on the rise and now you're looking at full-term babies weighing less. It's just not a sign of good health," he said.
Even though the small decrease won't put the health of the average newborn at risk, the trend needs to be curbed, said Dr. Garrett Colmorgen, an obstetrician who is on the board of directors for the March of Dimes Delaware chapter. Birth weights had climbed steadily from the 1950s into the 1990s.
"This study tells you that something is going on that doesn't make sense," Colmorgen said.
Findings unexpected
The analysis was based on nearly 37 million single births and the findings were published in the January issue of the medical journal Obstetrics and Gynecology. Only babies born between 37 weeks and 41 weeks of gestation -- the period in which babies are considered full-term -- were considered.
The study accounted for factors such as how much weight mothers gained during pregnancy and whether the delivery was induced or was by cesarean section. Maternal health issues, such as smoking and hypertension, also were considered.
Based on what is known about pregnancy and health, researchers expected birth weights to go up instead of down, said Dr. Emily Oken, an author of the paper and an assistant professor in the department of population medicine at Harvard Medical School.
"The findings were unexpected and somewhat surprising," she said. "We know that mothers are continuing to get heavier during pregnancy and secondly, we know that they are gaining more weight during pregnancy."Ilka Riddle gained 35 pounds. She isn't concerned about her daughter, who was born one week before her due date. Annika has always scored well during her routine checkups.
"She's on the smaller end of the scale, given her weight and height, but I'm not too concerned because she's developing normally -- and she's been really healthy," said Riddle, who is in her 30s and plans on having another child.
An optimal range for birthweight is between 6 pounds, 10 ounces and 8 pounds, 14 ounces, according to the Ballard Score, a commonly used tool for gestational age assessment. While the new findings fall well within this range, the new study found a 1 percent increase in the number of the lowest-weight babies born at full term.
The less newborns weigh under the optimal range, the more at risk they are for health problems.
"They can face a brain disability and their organs are stressed and more prone to infection," G reenspan said. "They're more prone to lung disease. Almost all the factors that can impact a baby are worse in a small baby since their organs are not as well formed."
Unexplained drop
In 1990, birth weights in Delaware were actually slightly higher than the national average.
Officials with Delaware's Division of Public Health couldn't explain the dramatic drop, and local obstetricians said the trend hasn't been evident to them.
"When I think of small babies, I'm thinking about ones that are 5 pounds or less," said Dr. Richard Henderson, an obstetrician at St. Francis Hospital in Wilmington. "I haven't noticed that kind of decline."
"It's going to take more time to find out an answer," added Colmorgen, who is the medical director of Bayhealth Maternal Fetal Medicine Associates in Dover.
Two of Michele Bento's three girls were born slightly below the average weight, but most of her friends had babies who were larger.
"I'm curious to see why that trend exists," said Bento, who lives in Smyrna. "I was actually afraid of having a large baby because I know people who've had 9-pound and 10-pound babies."
Shelly Burack's two daughters were slightly less than average weight, while her boy was slightly more.
"I do see the trend as a concern," said Burack, who lives in Dover. "But I think so much of it really has to do with the mother's lifestyle. That's a factor that can lead to big babies and really, really small babies."