Bariatric Surgery and Pregnancy Outcomes

I believe in more rigorous testing and vitamin supplementation than is suggested in this article, but all things considered, this is a reasonably complete guide.

Bariatric surgery outcomes and pregnancy management

  • Avoid pregnancy for 12-18 months or until weight stabilises.
  • Oral contraceptives aren’t absorbed well after a hysterectomy, and the transdermal patch doesn’t work as well for people who weigh more than 198.4 pounds (90 kg). For full effectiveness, IUCs or injections are recommended, along with regular use of condoms.
  • Iron, B12, folate, and calcium deficiencies are the most common problems in post-RNY pregnancies. There is no evidence that pregnant women need more protein unless they are losing weight or their baby is growing slowly.
  • Folate deficiency is a big worry because it can cause birth defects in the brain and spine, but it is rare.
  • After RNY, patients should take 40–65 mg of iron, 1200–1500 mg of calcium citrate, and B12.
  • Due to dumping, people who have had a sleeve gastrectomy may not be able to handle the usual 50-gram or 100-gram glucose tolerance test. Instead, you should do a 2-hour post paradinal test.
  • Follow the levels of haemoglobin, hematocrit, serum iron, ferritin, erythrocyte folate, methylmalonic acid, albumin, prealbumin, serum calcium, phosphate, and 25-hydroxyvitamin D. Erythrocyte folate is a better sign of a true deficiency, and MMA is a better way to spot a vitamin B12 deficiency.
  • RNY can cause serious GI problems during pregnancy, most notably an internal hernia, which can block the small bowel.
  • The most common problems after gastric banding were band leakage and band migration, which both needed surgery to fix.

Management of Pregnancy After Bariatric Surgery and Outcomes of Pregnancy

In the United States, especially among women of childbearing age, obesity has become a big problem in the last few decades. 72% of people who have any kind of bariatric surgery are women, and the vast majority of them are still able to have children.

As a result, obstetricians are seeing more and more women who have had bariatric surgery. They may need help from bariatric surgeons to learn more about the unique issues involved in caring for these patients. In 2004, a study on obesity in the United States showed that 33.2% of women 20 years old or older were obese and 6.9% were morbidly obese.

Many complications in obstetrics and gynaecology often happen in this group of patients.

First, obesity makes it harder for people to get pregnant, and second, obese people who do get pregnant are more likely to have problems like preeclampsia, pregnancy-related high blood pressure, venous thromboembolism, gestational diabetes, shoulder dystocia, and foetal macrosomia, among many others. 3,4 Bariatric surgery gives women who are morbidly obese a chance to get healthier and have more children.

When to get pregnant after bariatric surgery

Because women lose a lot of weight after bariatric surgery, getting pregnant is usually not a good idea for the first 12 to 18 months or until their weight stabilises. This is a unique problem when it comes to taking care of these women, since weight loss often leads to a more regular ovulation cycle and more babies. Deitel et al. found that of the 32 women (29%) who had problems getting pregnant before having bariatric surgery for morbid obesity, nine got pregnant after the surgery.

Also, there is a lot of disagreement about which method of birth control is best for these patients. After a gastric bypass (GBP), oral birth control pills don’t work as well, and the transdermal birth control patch doesn’t work as well for people who weigh more than 90 kg. 6,7 Patel et al. suggest using either intramuscular depomedroxyprogesterone injections or intrauterine devices along with regular condom use. However, one in three women who take depomedroxyprogesterone gain weight. 

Nutritional Deficiencies after Bariatric Surgery and the Outcomes of Pregnancy

In post-GBP pregnancies, iron, vitamin B12, folate, and calcium deficiencies are the main nutritional concerns. Even though protein deficiency after surgery is a concern, there is no evidence that pregnant post-GBP patients need more protein than the 60g that is recommended for either pregnant or post-GBP patients. 10 Patel et al. started giving patients extra protein when they got pregnant within the first year of surgery. They also recommend giving patients extra protein by mouth if they lose weight or stay the same weight during pregnancy or if their baby’s growth is below the 50th percentile.

Folate deficiency is even more of a worry because neural tube defects (NTDs) can be very bad and can only be fixed surgically if the baby lives. Haddow et al. wrote about three cases of NTDs in 35 pregnancies that happened after GBP.

Knudson et al. argued about how important this case report was, since the pregnancies happened 6–8 years after the surgery. None of the three women who gave birth were taking prenatal vitamins, two of them had low serum B12 levels, and only one of them had borderline low folate levels. 12 Also, when they looked at 77 pregnancies after the GBP, they didn’t find any NTDs. Some people say that GBP patients need to take more folate to lower their risk, but there isn’t much evidence to back this up.

To lower the risk of NTD, these women should get at least the 400mg of folic acid that is recommended for all women of reproductive age. Also, we now know that obese women have a much higher chance of getting NTDs than women with a normal body mass index (BMI). No matter how much folic acid the mother eats, their risk of NTD goes up proportionally if she weighs more than 70 kg. So, the risks of NTD in pregnancies after GBP must be weighed against the risks of being overweight during pregnancy without surgery.

Gurewitsch, et al., published a case of a patient with GBP who had severe iron and cobalamin deficiencies at six weeks of pregnancy. Even though the cobalamin deficiency could be treated, the iron deficiency could not be fixed with oral supplements. The anaemia could only be fixed with a blood transfusion. Patients with post-GBP, especially those trying to get pregnant, should take 40 to 65mg of iron in the form of ferrous sulphate or ferrous fumarate. Ferrous fumarate may cause less stomach upset than ferrous sulphate. Calcium should be given in the form of calcium citrate at a dose of 1,200 to 1,500 mg per day. B12 can be given orally every day or intramuscularly once a month at a dose of 350 to 1,000 mg.

Most of the time, doctors tell patients to wait to get pregnant because they are worried about micronutrient and vitamin deficiencies. However, recent data comparing patients who got pregnant within the first year after surgery to those who waited until after a year showed no significant cases of malnutrition, bad outcomes for the foetus, or pregnancy complications in either group.
Dao et al. looked at 34 patients, 21 of whom got pregnant in the first year and 13 in the second.

Antenatal complications and foetal outcomes, such as type of delivery, foetal birth weight, major complications (preeclampsia and miscarriages), and minor outcomes (preterm labour, high blood pressure, cholelithiasis, and iron deficiency), were similar between the two groups. It’s important to note that the weight of the mothers was very different between the two groups. At the time of surgery, the groups had similar average BMIs, but the early group had a BMI of 35 when pregnancy started, while the later group had a BMI of 28. So, the early group gained an average of only four pounds while the late group gained an average of 34 pounds.

Prenatal screening tests for people who have had bariatric surgery

All pregnant women should get tested for gestational diabetes. However, people who have had GBP may not be able to handle either the classic 50-gram glucose challenge or the 100-gram oral glucose tolerance test because of dumping syndrome. Dumping syndrome happens when the hyperosmolar contents of the stomach are dumped quickly and directly into the small bowel after GBP. This causes fluid to move into the bowel lumen, which causes distention.

Patients with early dumping syndrome have stomach pain, bloating, nausea, vomiting, and diarrhoea. Later, low blood sugar is caused by the release of too much insulin. So, people with late dumping syndrome have a fast heart rate, palpitations, agitation, and sweating.

Landsberger, et al., suggested using modified glucose testing. They suggest getting a blood glucose level when the person is fasting and a level two hours after eating the most carbohydrate-heavy breakfast the person can handle.

Normal glucose levels are less than 95 mg/dL when you are fasting and less than 120 mg/dL two hours after eating. Landsberger also says to keep an eye on your haemoglobin, hematocrit, serum iron, ferritin, erythrocyte folate, methylmalonic acid, albumin, prealbumin, serum calcium, phosphate, and 25-hydroxy vitamin D levels. They say that erythrocyte folate is a better sign of a true deficiency than serum folate, which only shows how much folate was eaten recently, and that methylmalonic acid is a better way to find out if someone doesn’t have enough vitamin B12. Lastly, Wax et al. suggest that screening for a-fetoprotein in the mother’s blood and ultrasounds be done in the second trimester, even though the risk of NTDs is theoretical based on the data we have now.

Less babies are dying before birth after bariatric surgery

Up until now, we’ve mostly talked about the risks of pregnancy after bariatric surgery. However, it’s important to compare those risks to the risks of pregnancy in obese people. Skull et al. looked for women who had successful laparoscopic adjustable gastric banding (LAGB) surgery and compared their pre- and post-surgery pregnancies. 22 The postoperative pregnancies in the group of 44 women (80 pregnancies) had a significantly lower average weight gain for the mothers (3.7 kg vs. 15.6 kg in the non-LAGB group) and a significantly lower total number of complications (including diabetes, pregnancy-induced hypertension, preeclampsia, and eclampsia). There were no big differences in the weights of the babies or how they were born between the two groups. Patel et al. found that their Roux-en-Y GBP patients lost the same amount of weight as both non-obese and obese women.

Ducarme et al. found that in their group of patients, the risk of preeclampsia, gestational diabetes mellitus, low birth weight, and foetal macrosomia was significantly lower in the LAGB group than in the obese control group.

Dixon, et al. compared data from patients’ first pregnancy after LAGB with data from their second-to-last pregnancy before LAGB and a group of obese people with the same weight.

Preeclampsia and high blood pressure caused by pregnancy were much less common in post-LAGB pregnancies than in the other two groups. Also, they had a lot less cases of gestational diabetes than the obese group that was matched to them.

What Happens to Pregnancies After Bariatric Surgery

People who have had bariatric surgery have been shown to have more caesarean sections. Sheiner et al. compared the births of 298 women who had bariatric surgery to the births of 158,912 women who did not have surgery. Even though he took other factors into account, he still found a strong link between bariatric surgery and caesarean section (including previous caesarean delivery, obesity, fertility treatments, premature rupture of membranes, labour induction, diabetes mellitus, hypertensive disorders, and foetal macrosomia).

Patients who had bariatric surgery were more likely to have a caesarean birth (25.2% vs. 12.2% in the control group). This study looked at people who had any type of bariatric surgery (open, laparoscopic, restrictive, or malabsorptive) and found that the results were the same for all of them. There were also links between bariatric surgery and macrosomia, premature rupture of membranes, and inducing labour. However, Sheiner’s control group had much lower BMIs than his post-bariatric surgery group. Even though there is a strong link between bariatric surgery and caesarean, it can’t be explained by how the body works, so some people think it’s just because of provider bias.

pregnancy after weight loss surgery Complications

Roux-en-Y gastric bypass may cause serious digestive problems during pregnancy, such as an internal hernia that blocks the small intestine. Due to the increased pressure inside the abdomen, pregnant women may be more likely to get a hernia.

When you look at the research, you can find eight cases like this. Five got better after surgery to reduce and fix the internal hernia or remove part of the small intestine (some also involved caesarean section with or without bilateral tubal ligation).

In one case, the mother had deep vein thrombosis and endometritis, which made things worse. In another, the mother died, and in the last, both the mother and the 31-week-old foetus died, even though the foetus was delivered by emergency caesarean section.

Lastly, Wax et al. wrote about a case that was complicated by intussusception. The problem was fixed so that neither the mother nor the baby had any more problems. Between surgery and getting pregnant, it took these people anywhere from four months to two years.

The most important thing to learn from these cases is that many of these patients’ symptoms were subtle and could have been mistaken for more common, harmless obstetric complaints like “morning sickness,” Braxton-Hicks contractions, hyperemesis, and gastroesophageal reflux. In the case report about the mother and baby who both died, doctors thought at first that she had pancreatitis. Many patients have nausea, a loss of appetite, and mild, sporadic stomach pain, but not many of them throw up. Connolly et al. did a study to find out what causes intestinal obstruction during pregnancy. They found that most of them (55%) were caused by scar tissue from a previous surgery.

Obstruction is most likely to happen to pregnant women at three different times: when the uterus becomes an abdominal organ in the middle of pregnancy, when the foetal head descends in the third trimester, and right after giving birth, when the size of the uterus changes quickly.

It is important for bariatric specialists, patients, and their obstetricians to know about these possible complications and when they are most likely to happen. This is because the symptoms can be subtle, and internal hernia and bowel ischemia can be fatal if they aren’t caught early.

Laparoscopic gastric banding that can be changed. LAGB gives pregnant women more options for how to deal with weight gain. Some bariatric practises are more cautious and deflate all of their bands when a patient is first told they are pregnant and feeling sick. Weiss et al. deflated the bands in all seven pregnancies (average BMI of 34.8) to relieve nausea and vomiting, but this did not help symptoms.

In the five births that went well, patients gained an average of 5.9kg. Dixon et al. took fluid out of all the bands at the start of pregnancy (n=22), and then at 14 weeks, they put fluid back in as needed to control weight gain. At 36 weeks, the bands were deflated as per the protocol. This led to an average weight gain of 8.3kg. 38 They also said that three patients had their bands removed and didn’t get any more care until after they gave birth:

Two of these three pregnancies caused the woman to gain too much weight (19kg and 26kg). Skull et al. set a goal for the least amount of weight gain for the mother, but only 18% of the 49 LAGB pregnancies met that goal (primarily band deflation or complete emptying, although one patient had fluid added to the band). They didn’t talk about the reasons for the changes in detail, but the way they handled things led to an average weight gain of only 3.7 kg, and the rate of complications in newborns was the same in both groups.

The most common problems after LAGB were leaky bands and bands that moved. At least one of each was found in each of these studies. Even though these problems needed surgery to fix them, neither the mother nor the baby were hurt by them.

There are also reports of pregnancy problems that are much worse after LAGB. Skull et al. reported two cases of gastric prolapse that needed laparotomy and band removal. However, both patients had peri-gastric band positioning, which is linked to a higher risk of gastric prolapse than the pars flaccida technique. Dixon said that he knew of one woman who had hyperemesis. Because she lived far away, her band wasn’t deflated until late in her pregnancy. She had to be put into labour, and the band was deflated afterward because she kept throwing up. During her third trimester, another woman got cholelithiasis that was made worse by pancreatitis. Her band was completely deflated when she was told she had biliary colic. Even though she lost weight overall during her pregnancy, she had an easy delivery and an easy cholecystectomy six weeks after giving birth. Lastly, Erez et al. wrote about a case in which a woman came to the hospital at 35 weeks with nausea and pain in her stomach. 40 She was put into labour, but two hours later, she had a sharp pain in her stomach and signs that the baby was in trouble. She needed a laparotomy and caesarean delivery to fix a perforated ulcer at the band site. Both the mother and the baby lived.

A Summary of Suggestions

When caring for obstetric patients who have had bariatric surgery, there are a lot of complicated things to think about. So, it’s important to use a multidisciplinary approach with open communication between the patient, the bariatric surgeon, the obstetrician, and the dietitian. Before deciding to have bariatric surgery, it’s best to talk to the patient about whether or not they want to have children in the future.

This makes sure that patients have the right kind of birth control while they are losing weight quickly, so that they don’t get pregnant by accident. After getting pregnant, a dietitian should be brought in to check for and treat any nutritional deficiencies.

Special obstetric screening may be suggested, such as modified glucose testing, maternal serum a-fetoprotein testing in the second trimester, monthly ultrasounds to make sure the baby is growing properly, and anatomic ultrasounds. Even for common complaints like nausea and vomiting, obstetricians and bariatric surgeons must be aware of serious complications like internal hernias in the middle to late stages of pregnancy.

Even though bariatric surgery has clear benefits, especially when compared to the risks of being overweight during pregnancy, a lot is still unknown. This is likely to change as the number of bariatric procedures done on women of childbearing age goes up. Larger studies are needed to come up with definitive protocols for contraception, prenatal screening, prenatal band management, and delivery guidelines for these patients, but the above is a collection of what we know now that we can build on.

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