Obese women have a higher risk of experiencing several complications during pregnancy, such as preeclampsia, hypertension, and postpartum weight retention. Their fetuses are additionally in danger and at higher risk of being born prematurely, stillborn, having a birth defect, or a number of other issues. Studies have also shown that children who have been born to obese women accumulate extra fat in the womb.
Thus, many women want to lose weight before pregnancy. There are currently no other long-term observable options for weight loss other than bariatric surgery, and the surgery seems to have many positive effects on the pregnancy. It boosts fertility in women and it reduces the risks of complications that are common in obese women.
Researchers at the University of Mississippi Medical Center wanted to find out whether it was purely beneficial for mothers to have offspring after surgery. In their first study, they found "that [the offspring] was shorter, smaller, and glucose intolerant,” says study author and metabolic disease expert Bernadette E. Grayson to LabRoots. The researchers also found that the offspring was more susceptible to developing long-term problems, such as diabetes and obesity.
In her new study, Grayson wanted to identify what was happening in the placenta and fetus that could be driving the issue. Her team put Long-Evans rats on a high fat diet for 3-weeks. They then performed either a vertical sleeve gastrectomy or a placebo surgery on the each rat. The vertical sleeve gastrectomy removed 80 percent of the rat’s stomach.
The females were mated after the surgery. During the first two weeks of pregnancy, the rats who underwent weight-loss surgery gained weight and took in a similar amount of calories to the control rats. Between day 12 and 18 of their pregnancies, the gastrectomy rats lost weight. On day 19, the researchers found the rats’ average blood pressure significantly dropped in comparison to the obese and lean controls. The same day, they euthanized the rats to analyze the contents of their wombs. They found the placental-to-fetal weight ratios suggested a placental insufficiency, meaning there was insufficient blood flow to the placenta.
The researchers found an increase of genes involved in oxygen deficiency and inflammation in the rats’ placentas. Oxygen deficiency and inflammation are both linked to weight gain. The data suggests weight-loss surgery alters mother's chemical balance, which in turn harms their offspring, causing obesity and diabetes.
The next step in research is to figure out what pathways are driving the alterations in the womb.
We need to understand whether we are creating a greater problem of metabolic disease for the next generation, and what we can do to stop it, Grayson says.
Grayson presented her findings today, November 19, 2015, at the
APS Conference: Cardiovascular, Renal and Metabolic Diseases: Physiology and Gender.
Sources:
Lead researcher Bernadette E. Grayson, personal communication (11/19/2015)
Conference abstract: "In Utero Consequences of Rodent Vertical Sleeve Gastrectomy on Maternal Health and Feto-placental Development”
Press release: https://www.newswise.com/articles/children-born-to-women-after-bariatric-surgery-at-higher-risk-of-obesity-diabetes
