Many women becoming pregnant too soon after bariatric surgery, study shows
Doctors are concerned about the results of a study showing that almost half of the women who had had bariatric surgery either tried to get pregnant or did not use birth control in the first two years after surgery.
The results were collected over a seven-year period from 710 women ages 18-44 who are part of a multicenter, long-term observational study of people undergoing firsttime bariatric surgery, known as LABS-2. The median age of the women before their operation was 34.
Of the 670 women who reported on their use of contraception, 41.5 percent had unprotected sex within a year and 4.3 percent were trying to get pregnant. The percentage of women trying to conceive grew to 13.1 percent in the second year.
Women are advised to wait at least 18 months after bariatric surgery before getting pregnant, according to George Eid, director of the Allegheny Health Network Bariatric & Metabolic Institute. He had been affiliated with the LABS-2 study before joining AHN four years ago.
Women who were married or said that pregnancy was an important goal were more likely to become pregnant within 18 months of surgery, the study showed.
Bariatric surgery can give a woman a better chance at a successful pregnancy if she had trouble before, Dr. Eid said. Obesity increases the risk of infertility, polycystic ovary syndrome and related conditions, he said, and pregnant obese patients are higher pregnancy risks.
“Bariatric surgery definitely helps reverse some of those conditions,” he said, “but we don’t want patients to get pregnant during rapid weight loss.” It’s in the first year, or year and a half, when the pounds come off most quickly, he said.
“There have been some [cases] where the babies are fine, but we can’t draw any conclusion that this is OK. What we worry about is vitamin deficiency in the mothers and also neural tube defects in babies.”
The American College of Obstetricians and Gynecologists warns that increased fertility after bariatric surgery can lead to an unplanned pregnancy. Delaying it allows a woman to reach a stable weight during fetal growth. ACOG says getting pregnant within two years of surgery has been found to increase the risk for prematurity, newborns who are small for their gestational age and admissions to neonatal intensive care units.
Researchers in the latest LABS-2 report, published in the journal Obstetrics & Gynecology, cited a need to identify which patients are at risk for early conception, calling it a “public health concern.”
“I think there’s going to be more about this,” said the study’s first author, Marie Menke, assistant professor of obstetrics, gynecology and reproductive sciences at the University of Pittsburgh School of Medicine and Magee-Womens
Hospital of UPMC.
“More women are getting surgery, there are more women of childbearing age with obesity and more adolescent and early-age bariatric surgery,” she said. “This is something that is going to have to be followed over time.”
She said better counseling of patients before surgery may be the answer.
“Younger women are more likely to be getting pregnant during the early time period, when they’re not supposed to.”
Although surgeons say they counsel patients to delay pregnancy, that might not be enough.
“I think what we did see is if they didn’t use it before surgery, they were not likely to use contraception afterward,” she said.
Dr. Menke, a fertility specialist, said the study only looked at whether women were following recommendations and whether they were actually getting pregnant.
Many women didn’t report the outcomes of their pregnancies.
“What we’re seeing is a need for a multidisciplinary approach,” she said. “Bariatric surgeons should have a team member to talk about contraception and why it’s important, [such as] the specific risks to the pregnancy, getting pregnant during that time frame.”
Her team is continuing to study infertility and obesity.
“We just don’t know a lot about obesity,” she said. “We have to take a look back and challenge some of our assumptions.”
Dr. Eid said patients are routinely counseled about the importance of delaying pregnancy, but there’s no consensus on the best method to use in the year and a half after surgery.
The women in the LABS-2 study underwent all types of bariatric procedures, primarily the Roux-en-Y gastric bypass, and they also used a variety of contraception methods.
“What happens in rapid weight loss is there are hormonal changes in the body,” Dr. Eid said. “The oral contraceptives they were on before surgery will not provide the protection they need. Many papers are out there looking at the best methods to use, but the jury is still out on this.”