Bariatric surgery and birth outcomes

In the US, 41.1% of women of childbearing age (over the age of 20) are obese.

Women who are overweight or obese want the best for themselves and their children as much as any woman; and a good many women of childbearing age are considering bariatric surgery to help. Statistics report that of the amount of people participating in bariatric surgery, 80% of them are women.  Thirty percent of those ladies have plans to start their families after their healing time post surgery.


In a recent systemic review published in the Journal of the Academy of Nutrition and Dietetics, a group of doctors and dietitians attempted to better understand the effects, if any, bariatric surgery had on birth and health outcomes for both mom and baby.

The results, though, are sadly very mixed and inconclusive for many of the health outcomes researched. One of the reasons, they say, is due to the fact that the type of bariatric surgeries (of which there are several and can impact a woman’s weight loss in different ways) were not delineated in any of the studies. Another unknown is the amount of time that lapsed between the surgery and pregnancy/delivery. This makes it difficult to be able to make connections between the extremely varied results they see.

One of the most significant of their findings, though, out of the thirteen studies this medical team reviewed was that mothers who had undergone the surgery had distinctly smaller babies than BMI-matched moms in control groups. On one hand, this shows a great reduction in risks for larger babies/macrosomia or birth injuries related to bigger sized babies.

But this greatly concerns doctors for other reasons.

While some studies varied greatly in the consistency of these findings, the fact that a good amount of studies shows a marked difference in sizes of babies born (albeit still within normal ranges for many), it is still a concerning trend. It could indicate a greater risk overall for small for gestational age (SGA) (lower than 10th percentile for average wt) or low birth weight (LBW) (less than 5 lbs 5 oz) babies. This would give anyone pause.

SGA or LBW babies are at higher risk for low oxygenation at birth, lower APGAR scores, difficulty in blood sugar regulation, compromised ability or strength to feed well (either bottle or breast) and therefore to gain weight, have a harder time regulating their body heat, have a stronger vulnerability to infections, and most worrisome of all, a higher risk of SIDS. It can also have long reaching effects for the baby long into adulthood, with an increased risk of obesity.

Any kind of surgery that greatly impacts the way a person’s body digests and absorbs nutrients from food is of course a huge concern during pregnancy. A growing fetus depends heavily on mom’s body absorbing nutrients to pass on to her through the placenta. When calories or nutrients are restricted as they would be in some bariatric surgeries such as the gastric bypass, or the Roux-en-Y procedure, a fetus’ health and growth could also be at risk.

Just the fact that post surgical rapid weight loss and nutrient deficiencies are a common side effect within the first two years, most obgyn’s recommend holding off on pregnancy during that space of time.

On the plus side, the review found no correlations between the surgery and maternal gestational weight gain, miscarriages, stillbirths, preterm birth, or birth complications for the baby such as congenital malformations or NICU stays. But the jury is still out on issues such as pre/eclampsia, gestational diabetes risks, or its impact on c-section rates.

So is bariatric surgery worth some of the risks, or does it create new ones? More research needs to be done to ascertain those answers.

In the meantime if you are considering this surgery before pregnancy, do your research and weigh the pros and cons for yourself. Types of bariatric surgeries and length of time between the surgery and pregnancy can all have more positive effects and lead to healthier birth outcomes.


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