Greater fertility, vitamin deficiencies may follow bariatric surgery for women
Women who undergo bariatric surgery should wait until weight loss has stabilized and vitamin levels are normalized before trying to become pregnant, according to findings from a systematic review and meta-analysis.
In a review of 51 articles examining associations of bariatric surgery and periconception maternal health, women who underwent surgery were more likely to have increased fertility and restored menstrual cycle regularity compared with those who did not have surgery, though several studies revealed vitamin deficiencies among pregnant women after bariatric surgery.
“Bariatric surgery results in improved fertility outcome, with no difference in rates of miscarriages and congenital malformation,” Katinka Snoek, MD, a PhD candidate in periconception epidemiology in the department of obstetrics and gynecology at Erasmus MC University Medical Center and Sam Schoenmakers, MD, PhD, an obstetrician in the department of obstetrics and gynecology at Erasmus MC University Medical Center, told Healio. “It underlines the need for providing and personalizing preconception care for women after bariatric surgery. We recommend preconception care, including postponing pregnancy until weight loss has stabilized, irrespective of the surgery-to-pregnancy interval, and until maternal vitamin status is normalized. Therefore, regular monitoring of vitamin status and vitamin supplementation to restore deficiencies is recommended.”
Researchers conducted a search of the MEDLINE, Embase, PubMed, Web of Science, Google Scholar and Cochrane databases for studies on bariatric surgery and its effect on periconception maternal health parameters. Studies investigating endocrine changes after bariatric surgery, associations between bariatric surgery, postsurgical vitamin status before conception and during the first trimester, and the prevalence of first-trimester miscarriage were included. Meta-analysis was performed on fertility outcomes, menstrual cycle, miscarriages and congenital malformations.
There were 51 articles included in the meta-analysis, of which six examined malabsorptive procedures, 11 examined restrictive surgery and 37 looked at a combination of surgeries or did not specify the type of surgery.
Several studies found changes in vitamin status during pregnancy. In high-quality studies, the effect of bariatric surgery on vitamin status was inconsistent. One study found pregnant women who underwent Roux-en-Y gastric bypass had a ninefold higher risk for developing vitamin A deficiency during pregnancy compared with those who did not undergo surgery, and another study found 72% of women had inadequate vitamin D status during the first trimester of pregnancy after gastric bypass surgery despite receiving daily vitamin D supplementation. Six low-quality studies found bariatric surgery was negatively associated with vitamin A, B1, B6, B12, folate, C, D and K levels.
“We advise adequate, preferably patient-tailored, supplementation until appropriate vitamin serum levels are reached and weight has stabilized, before a patient tries to become pregnant,” the researchers wrote. “Bariatric surgery has proven to be effective in the achievement of weight reduction, but the risks of iatrogenic malnutrition can also influence fetal growth and development and offspring health, even though the effects may not be directly visible and are largely unknown.”
In 20 studies examining periconception outcomes, women who underwent bariatric surgery had a decreased risk for infertility (risk difference = –0.24; 95% CI, –0.42 to –0.05) and were more likely to have menstrual cycle regularity restored (risk difference = –0.24; 95% CI, –0.34 to –0.15). Bariatric surgery was not associated with changes in miscarriage rate or congenital malformations. The researchers found substantial heterogeneity in the study populations, indicating differences in participants, interventions, study design and variation in effects.
“Although major weight loss was suspected to result in a decrease in infertility, the effect of bariatric surgery on fertility was impressive,” Snoek and Schoenmakers said. “Moreover, bariatric surgery was associated with a restoration of a regular menstrual cycles, suggesting a return in hormonal balances.”
Schoenmakers and Snoek said the review revealed the need for longer-term follow-up research during the periconception period as well as for offspring. The researchers are currently conducting a prospective ongoing cohort of pregnant women who underwent bariatric surgery that will evaluate outcomes from the preconception period onward.
“The possible side effects of over-supplementation need to be investigated, and the possibilities in an individualized approached should take precedence,” Snoek and Schoenmakers said.
For more information:
Katinka Snoek, MD, can be reached at firstname.lastname@example.org.
Sam Schoenmakers, MD, PhD, can be reached at email@example.com.