A recent study considered what recommendations might be important for women who want to become pregnant after they have had bariatric surgery to treat obesity.
The authors concluded that women should wait at least a year, preferably 18 months, before becoming pregnant after the surgery. They may need additional nutrient supplements, and they should limit their pregnancy weight gain.
The authors also recommended that women discuss their options related to obesity, pregnancy and bariatric surgery with their doctors to make informed decisions.
"Ask your doctor about pregnancy after surgery."
The study, led by Rahat Khan, MBBS, MRCOG, an OB/GYN at Princess Alexandra Hospital in Harlow in the United Kingdom, reviewed the current research related to pregnancy and bariatric surgery for obesity.
Obese women are more likely to have complications during pregnancy as well, so the researchers wanted to better understand possible pregnancy outcomes after a woman undergoes an increasingly used obesity treatment.
The National Institute for Health and Clinical Excellence in the UK recommends that morbidly obese women who have been unable to lose weight through lifestyle changes or medication could consider bariatric surgery.
The question is how long a woman should wait after she has bariatric surgery before she tries to get pregnant. The research on this question is sparse and sometimes contradictory.
Some studies found a higher risk of preterm (early) birth among women who got pregnant within a year of their surgeries.
Another study found a higher miscarriage rate (31 percent) among women who became pregnant within 18 months of their surgeries, compared to the miscarriage rate (18 percent) among women who waited at least 18 months after their surgery to become pregnant.
However, most studies did not find a higher risk of miscarriage, high blood pressure or gestational diabetes among pregnant women who had had bariatric surgery, regardless of how long they waited until after the surgery before becoming pregnant.
The research also found no differences so far in children's birth weight, fetal growth restriction or cesarean section rates among women who conceived within a year of their surgery versus more than a year post-surgery.
Yet, since the evidence in this area is still thin and there are some studies to support the recommendation, the authors said that women should be advised to wait 12 to 18 months after their bariatric surgery before trying to become pregnant.
Jennifer Mushtaler, MD, an obstetrician in Austin, Texas and a dailyRx expert, said waiting after surgery to conceive also allows a woman to achieve a more consistent body weight.
"The greatest weight loss occurs in the first year after surgery, so many surgeons and obstetricians advise waiting at least one year after surgery before attempting pregnancy to allow weight to stabilize," Dr. Mushtaler said.
The researchers also noted, however, that women tend to have improved fertility after bariatric surgery compared to morbidly obese women who do not undergo the surgery or otherwise lose weight.
The researchers noted that women who become pregnant after having bariatric surgery may experience nutritional deficiencies, especially with folate and vitamin B12. Therefore they should work with their doctors to ensure they are getting all the nutrients they and their developing babies need.
"Women will require additional levels of iron, calcium, folate, vitamin B12, protein and fat-soluble vitamins alongside diagnosis and treatment of other nutritional deficiencies," the authors wrote.
In terms of weight gain during pregnancy, the authors said that the ideal amount for these women is between 15 and 24 pounds.
The authors also reviewed some of the complications that are possible among pregnant women who have had bariatric surgery. For those who receive gastric-banding, it is possible for the band to move or cause leaking in about 24 percent of cases. Only 4 percent of patients needed the band removed.
Overall, however, there were fewer complications among pregnant women who had bariatric surgery compared to morbidly obese pregnant women.
For example, one study found that 0 percent of pregnant women who had had bariatric surgery developed gestational diabetes, compared to 22 percent of obese pregnant women.
Similarly, the rate of pre-eclampsia in pregnant women who had had bariatric surgery was 0 percent, compared to 3.1 percent in obese pregnant women. Pre-eclampsia is a condition involving high blood pressure and protein in a woman's urine. The only treatment is to deliver the baby.
Dr. Mushtaler said her experiences in treating women who became pregnant after having had bariatric surgery match up with what the researchers found in their review.
"My experiences are consistent with the data in that fertility is improved and rates of complications are less," Dr. Mushtaler said. "We do watch the infants for risks of growth restriction and we advise patients to take nutritional and vitamin supplements but limit caloric intake."
In comparing women who had bariatric surgery to healthy weight women who have not had the surgery, there may be additional risks for miscarriage for two particular bariatric procedures: biliopancreatic diversion (BPD) and Roux-en-Y gastric bypass (RYGB).
One study found a miscarriage rate of 34.7 percent among women who had RYGB and 4 percent among women who had BPD. There was not evidence to show a higher miscarriage rate among women getting laparoscopic adjustable gastric banding (LAGB).
The authors concluded that women who have had bariatric surgery or are considering it should consult with their doctors, especially if they plan to have children.
"Both obstetricians and surgeons should consider post-bariatric surgery pregnant women as high risk," the authors wrote. "Optimal education should be encouraged in these individuals so that they can make well-informed decisions about planning pregnancy after weight loss surgery."
The study was published January 11 in the journal The Obstetrician and Gynaecologist. The research paper did not note any sources of funding. The authors declared no conflict of interest.