Pregnancy considerations for gastric sleeve & bypass surgery


How many people does obesity affect in Australia?

In Australia, 62.8% of adults are overweight or obese, this is comprised of 35.5% of people that are overweight and 27.5% that are obese. Since 1995 the trend has been that weight is slowly increasing over time, with the average female’s weight increasing 4.4kg from 1995 to 2011-12 and the severity of obesity also climbing with a 4.6% increase in people achieving a BMI 35. (ABS 2011-12)

This means we have a significant proportion of females at reproductive age that are obese. Obesity rates climb throughout the age brackets; 18-24, 25-34 and 35-44 at 15.1%, 20.5% and 28.4% respectively. (ABS 2011-12) Although, this data includes both men and women, as the rates of obesity are the same amongst both genders it can be assumed that there is at least a 7- 15% of females who are obese at reproductive age.

Females who are obese are at risk of infertility. They have more complications during conception and place their infant at risk of multiple and varied health complications. It’s for this reason that interventions such as lifestyle modification, in combination with more drastic measures such a bariatric surgery, are being sort to decrease the disease burden on the health care system and increase the chance of conception and giving birth to a healthy baby.

Obesity & Infertility

In a cohort study by Jan Willem van der Steeg et al. 2008, researchers found that for every BMI unit increase, above a BMI of 29, the probability of pregnancy in sub-fertile ovulatory women reduced by 5%. This is comparable to a 1 year increase in biological age. This is concerning outcome given the number of women who are currently obese within the Australian population.

Infertility is just one area that obesity can affect. It has long been known that complications can also occur at birth and to the infant. In a large prospective screening study 1473 obese and 877 morbidly obese patients showed positive association between obesity and risk of gestational hypertension, preeclampsia, gestational diabetes and a fetal birth weight greater than 4.5kg. Obesity is a significant risk factor for undesired obstetric outcomes. (Weiss et al 2004)

Bariatric surgery & fertility

Women who are obese have higher risk of pregnancy complications to themselves and the baby. M.Kominiarek 2009, suggests obesity increases the chances of:

  • Maternal gestational diabetes
  • Preeclampsia
  • Caesarean delivery
  • Infectious morbidity
  • Increasing the stillbirth rate to 2.1-4.3 higher compared to normal weight women
  • Miscarriage
  • Large for gestational age and macrocosmic infants
  • Congenital anomalies
  • Birth defects such as neural tube, cardiac defects and facial clefting

In the USA, bariatric surgical procedures have increased from 12,480 to 113500 from 1198 to 2005, with 80% of these cases being females of reproductive age. These types of procedures are also more commonly being performed on morbidly obese adolescents (M.Kominiarek 2009), which paves the way to a rise of women of reproductive age who have previously undergone bariatric surgery.

In obese infertile women, weight loss may improve fertility

It has been shown that a significant amount of weight needs to be lost to improve fertility. In a randomised control trial conducted by Meike A.Q Mutsaerts et al. 2016, they found that despite a 6 month lifestyle intervention program, that involved a 1200kcal diet and exercise activity target of 10,000 steps daily, it did not result in improved fertility. The program resulted in an average 4.4kg weight loss amongst study participants, however this small degree of weight loss was not enough to impact rates of pregnancy for 24months after the intervention.

Medical infertility treatment through IVF, had a similar rate of success, pregnancy and births, as a small amount of weight loss. The same study had a 22% drop out rate from the lifestyle based program from women who were activity seeking fertility assistance. A high dropout rate in obese populations for lifestyle-based interventions is not uncommon.

This means there is a proportion of the female population of reproductive age that could be potentially looking for alternative weight loss avenues, one with more predictable long term success and achieve a greater degree of weight loss. The most successful and common medical intervention used is bariatric surgery.

For the purposes of this review bariatric surgery will be referred to include gastric banding, gastric sleeves and Roux-enY bypass. Where malabsorption is discussed, this is typically seen post bypass or jejunoilleal procedures, so this will be addressed separately. Bariatric surgery is commonly available to people who are BMI greater than 40 or those with BMI of 35 and accompanied by other comorbidities. (M.Kominiarek 2009)

Bariatric surgery should not be performed for the purposes of fertility alone, however a lot of women are considering surgery for a variety of other medical reasons. Women are also experiencing unplanned pregnancies post-surgery because of its effects on fertility and the lack of education around contraception for this group.

With more women falling within this category and it’s growing every year, post bariatric surgery pregnancy accompanies many unanswered questions. This review attempts to address issues surrounding the impact of bariatric surgery on fertility of the female preconception.

Bariatric surgery & improving reproductive health

Bariatric surgery can result in up to 15-25% reduction in body weight. (Royal College of Obstetricians and Gynaecologist 2015)

This significant amount of weight loss increases the chances of a female falling pregnant naturally by improving PCOS, anovulation and irregular menses. (M.Kominiarek 2009) It also reduces the risk of a range of co-morbidities including: type 2 diabetes, hypertension , heart disease and cancer. It does this through improving the metabolic markers that are caused by being obese, for example insulin resistance and PCOS. Simply put, it doesn’t matter what type of surgery a female has, it’s the amount of weight loss that improves their ability to fall pregnant. On avager in the literature it seems a reduction in BMI by 5kg/m₂ is the magic number. (Royal College of Obstetricians and Gynaecologist 2015).

In regards to the health of the baby post-surgery a study by Nathalie Roos et al 2013, looked at 2562 obese women and matched them for maternal age, early pregnancy BMI, smoking state, educational level and year of delivery. They found that women who had undergone bariatric surgery had an increased risk of a small for gestational age (SGA) babies and a higher incidence of pre-term births. Researchers suggest women who have undergone bariatric surgery be considered a high-risk group despite improvements in health pre-pregnancy and should be monitored closely during pregnancy.

The potential risk of SGA births is that it increases the risk of the infant becoming obese and affected by metabolic syndrome in adult life. (Gasscoin G 2013)

On the other hand, there are improvements in other maternal outcomes post-surgery, that outweigh the previously mentioned risks such as; decreasing risk of gestational diabetes, pregnancy induced hypertension, large for gestational age babies, and congenital abnormalities. (Uzoma A 2013)

Uzoma A 2013, suggests that pre and postnatal care from a multidisciplinary team and use of nutritional supplementation can overcome a lot of the challenges post-surgery women face during pregnancy. Most of the negative outcomes are due to inadequate nutritional intake due to the surgery itself, especially malabsorptive surgeries. This can be overcome with dietary monitoring and regular interventions with a multidisciplinary team, which includes the use of a dietitian.

Nutritional concerns

Due to the very nature of these types of surgeries there are a number of nutritional concerns that need to be considered, including:

  • Smaller intakes that may result protein energy malnutrition for the growing foetus and during breast feeding. (M.Kominiarek 2009)
  • In malabsorptive bypass surgeries there may be loss of key nutrients (iron, calcium, folate, thiamine, B12 and fat-soluble vitamins) resulting in deficiencies. (Rhat Khan 2013) This is in addition to malabsorption of nutrients due to vomiting from morning sickness, that can occur in all women despite bariatric surgery. (Kominiarek 2009, Rhat Khan 2013)
  • Inability to ingest enough water to hydrate appropriately to assist in lactation.



As weight loss improves the rate of fertility contraception methods should be discussed with patients prior to surgery. The aim is to avoid pregnancy within the first 12months for up to 24months post-surgery. There is mixed opinion on how long this duration should be (Nathalie Roos et al 2013, M.Kominiarek 2009, Rhat Khan 2013). This recommended duration is to optimise the weight loss that can be achieved due to surgery, to avoid losing weight whilst pregnant (Royal College of Obstetricians and Gynaecologist 2015) and allow for any nutrition deficiencies to be corrected before conception.

Bariatric surgery for the purposes of fertility should be discussed with maternal age in mind. Early referral is recommended for women above age of 30years. Starting the process of surgery early will give women enough time to wait out the 12month post-surgery time period and to attempt IVF treatment safely. (Royal College of Obstetricians and Gynaecologist 2015)

If pregnancy occurs before 12-24months careful monitoring of nutritional status should be implemented to ensure a healthy baby. M.Kominiarek 2009 also suggests that ultrasound be used to monitor adequate foetal growth.

During pregnancy

Adequate nutrition and weight status should be monitored closely by their health care team during pregnancy to ensure women are meeting their RDI’s for essential nutrients and weight gain is appropriate for each stage of pregnancy. Weight gain should also fall within current recommendations for women based on their last pre-pregnancy BMI. (M.Kominiarek 2009)

Women who have had lap band surgery may also consider removing the fluid from the band to allow for an improved nutritional intake. This should be done with adequate support from a dietitian to implement lifestyle based weight control methods. (M.Kominiarek 2009)

It should also be noted that common morning sickness symptoms such as nausea, abdominal pain and vomiting during pregnancy are also symptoms of post-operative complications. This includes things such as internal hernias, band erosion and migration, bowel obstructions and anastomotic leaks. These symptoms should not be dismissed for morning sickness without further investigation. As this can delay diagnosis of complications arising post- surgery. (M.Kominiarek 2009, Rhat Khan 2013)

In patients with malabsorptive surgeries such as Roux-en –Y who experience dumping syndrome other alternatives should be sort to test for gestational diabetes. The standard diagnostic test used currently requires the use of 50g of glucose, which may cause adverse effects. Alternative fasting blood sugar readings 2 hours post meals for 1 week at the 24-28week gestation mark can be used.. (M.Kominiarek 2009)

This cohort may also need medications reviewed and swaps for fast-release forms, and use of non-steroidal anti-inflammatory drugs reconsidered. These types of medications are thought to increase the risk of gastric ulcerations postpartum in post bariatric patients. (M.Kominiarek 2009)


Bariatric surgery does not change the process or outcome of labour. Due to the nature of this cohort all risk factors associated with obesity such as; requiring more oxytocin, longer labour times and earlier labour are still present. This is because 80% of the women in this cohort still remain obese despite dramatic changes in weight due to surgery. If a patient has complicated and multiple abdominal surgeries for weight loss, this should be discussed with their doctor in case a caesarean birth is required. (M.Kominiarek 2009) There is no evidence that caesarean births are more prevalent in this cohort. (Rhat Khan 2013)

Post natal

This patient group is also at risk of significant weight regain during and post pregnancy. Weight gain should be monitored regularly and in line with usual recommendations for suitable weight gain during pregnancy (Royal College of Obstetricians and Gynaecologist 2015). Follow up post natal should include adequate planning to reduce weight and maintain sound nutritional practices and movement.

Breastfeeding may impacted if there is nutritional inadequacy. Malabsorption and restriction of energy and nutrients may affect the energy and nutrient content of breast milk, placing the baby at risk of failure to thrive. (Rhat Khan 2013)

Normal diabetes screening should done 2 years post pregnancy in women who have been diagnosed with gestational diabetes, with use of alternative testing methods for those with malabsorptive surgeries.

What can be done about excess skin?

Cosmetic surgery that aims to remove excess skin post bariatric surgery is also commonly pursued in this group with as much as 12% of patients undergoing cosmetic surgery. It is recommended that women wait until well after they have completed their families before doing this. Weight gain in future pregnancies could compromise the effectiveness and visual outcomes of cosmetic surgery. (Rhat Khan 2013)

Just note that in Australia skin removal is not funded by the public health system. If you have private health check that your insurer provides this elective surgery, as some do not include it in their policy’s.


  1. Education surrounding use of contraception to avoid unplanned pregnancies, until planning to conceive. Note that the absorption of oral contraception may be affected due to malabsorption induced by malsbsorptive bariatric surgery and may not be the best choice. Hormonal contraception is preferred. (M.Kominiarek 2009)
  2. Exercise daily to improve your metabolic health and pregnancy outcomes.
  3. Plan your pregnancy. This includes having regular blood tests whilst trying to fall pregnant to ensure nutritional adequacy for essential nutrients such as folate, iron, vitamin A,D, B1, B12 and k. Note supplemental vitamin A intake should not exceed 5000IU, as this has shown to cause birth defects. (M.Kominiarek 2009)
  4. 6 months prior to conception start folate and multivitamin supplementation have regular blood tests. It is thought that post bariatric mother may require more folate than normal (0.4mg daily) to reduce the risk of birth defects. This is because most bariatric patients cease recommended multivitamin supplementation long term and may have abnormally low intakes prior to conception. (M.Kominiarek 2009)
  5. Obtain a bone density test to pick up any demineralisation of bone. This will indicate if there is a prior inadequate intake of calcium and/or vitamin D.
  6. Wait 12-24months post pregnancy at a minimum before attempting to conceive.
  7. Have your diet assessed to reach the recommended amount of protein 60g daily during pregnancy. (M.Kominiarek 2009)
  8. Have your diet assessed to determine if you are reaching energy and micronutrient targets for pregnancy.
  9. During conception aim to eat small nutrient rich meals every 2-3 hours. This includes whole foods that are high in protein, minerals and vitamins including; lean meats, fish, eggs, nuts, low fat dairy products, vegetables and fruit. Continue with supplementation as directed.
  10. Limit the amount of high fat, high sugar processed foods. These foods cause a surplus of energy, with little of the essential nutrients needed for pregnancy.


There are many maternal health benefits to undergoing bariatric surgery. Women who are thinking of undergoing surgery for fertility purposes, should be encouraged to start the screening process early to ensure there is adequate time to conceive at a safer age and have a chance to try IVF if it is needed. However, I would strongly recommend using traditional weight loss methods initially to increase fertility and consider surgery again once your family is complete.

The surgery chosen should be an individual choice and considerations made to the idea of becoming pregnant in the future. Surgeries that are not malabsportive may be more appropriate for this group, such as the lap band or gastric sleeve. At least in the case of a lap band, it can be deflated during pregnancy to allow for adequate nutrition and easily refilled postnatal.

Women should plan their pregnancy and use contraception, to reduce the chances of unplanned pregnancies during the weight loss period. This will help avoid common nutritional inadequacies and health complications of the baby. Supplementation and intervention from a dietitian should also be started early.


  • Australian Bureau of Statistics. Australian Health Survey. 2011-12. Last updated 29/7/13. Accessed online 7/7/16
  • Australian Government Preventative Health Taskforce. Australia the Healthiest Country By 2020. Accessed online 5/8/16$File/obesity-jul09.pdf
  • Gascoin G, Glamant C. Long-term outcome in context of intra uterine growth restriction and/or small for gestational age newborns. Journal of Gynecology Obstetrics Biology and Reproduction. 2013
  • Jan Willem van der Steeg, Pieternal Steures, Marinus J.C.Eijkemans et al. Obesity affects spontaneous pregnancy chances in sub fertile, ovulatory women. Human Reproduction Vol.23, No.2. PP 324-328, 2008
  • Klem ML, Wing RR, McGuire MT, Seagle HM, HillJo. A descriptive study of individuals successful at long-term maintenance of substantial weight loss. American Journal of Clinical Nutrition 1997 August: 66(2):239-49
  • Kominiarek, ACOG Committee. Bariatric Surgery and Pregnancy. The American College of Obstetricians and Gynaecologist. Vol 113, NO.6, June 2009
  • Meike A.Q Mutsaerts, Anne M,Van Oers, Henk Groen, Jan M. Burggraaff, Walter K.H.Kuchenbecker, Denise A.M.Perquin, Carolin A.M.Koks, Ron Van Golde. et al. Randomized Trial of a Lifestyle Program in Obese Infertile Women. The New England Journal of Medicine. 374;20. May 19 2016
  • Rhat Khan, Bashir Dawlatly, Oliver Chappatte. Pregnancy outcome following bariatric surgery. Royal College of Obstertricians and Gynaecologists 2013
  • SM, Wing RR, Klem ML, McGuire MT, hill jo, Seagle H. Persons successful at long-term weight loss and maintenance continue to consume a low-energy, low fat diet. Journal of American Dietetic Association 1998 April:98(4):408-13
  • Sjöström L. Review of the key results from the Swedish Obese Subjects (SOS) trial- a prospective controlled intervention study of bariatric surgery. Journal of International Medicine March: 273(3):219-34. 2013
  • Royal College of Obstetricians and Gynaecologist. The Role of Bariatric Surgery in Improving Reproductive Health. Scientific Impact Paper No17. October 2015
  • Nathalie Roos, Martin Neovius, Sven Cnattingius, Ylva Trolle Lagerros, Maria Saaf, Fredrik Granath. Olof Stephansson. Perinatal outcomes after bariatric surgery: nationwide population based matched cohort study. BMJ 2013
  • The National Weight Control Registry
  • Weiss JL, Malone FD, Emig D, Ball RH, Nyberg DA, Comstock CH, Saade G. ET AL. Obesity obstetric complications and cesarean delivery rate-a population-based screening study. Journal of Obstetrics and gynecology. 2004 April 190(4):1091-7
  • Uzoma A, Keriakos R. Pregnancy management following bariatric surgery. Journal of Obstetrics and Gynaecology. 2013





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