Background and short summary Obesity negatively affects disrupts the hypothalamic-pituitary-gonadal axis through central and peripheral mechanism *ovarian hormonal balance between oestrogen, testosterone and progesterone, which are essential for reproductive health and overall well being *adrenal hormones such as cortisol, dehydroepiandrosterone sulphate (DHEA-S) and androgens, which are essential for metabolism, stress response and sex hormone production   Increase adipose tissue enhances the aromatase enzyme activity leading to higher oestrogen production Visceral adipose tissue also causes increase insulin resistance The imbalance of ovarian and adrenal hormones thus increases the risk for PCOS, infertility, pregnancy related issues and cardio-vascular disease in women of reproductive age     Bariatric surgery significantly *decreases androgen testosterone and androstenedione levels in women *increase anti Mullerian hormone (AMH), DHEA-S and sex hormone binding globulin (SHBG) *improves PCOS morphology: dysmenorrhoea (improve ovulatory dysfunction, reduce irregular menstruation, increase conception rate, reduce miscarriages) and hirsutism (43% reduction by 6 months after surgery) *also increase distal gut hormone secretion (GLP-1, PYY), change bile acid profile, modulate gut microbiome, improve insulin sensitivity which also have beneficial effect on reproductive health, improve fertility and improve pregnancy outcomes For pregnant mothers Special cautionary note for patients who became pregnant after sleeve or a gastric bypass procedure. Please ask your GP to do the usual antenatal blood test and have the multivitamin supplements as recommended. During pregnancy fetal growth and immunity require vitamin A, D and zinc. Brain and neurological development require thiamine (B1), iodine and omega 3 fatty acids. Deficiencies in vitamin C, B9, B12, E, zinc, selenium and iron had been linked to preterm birth and deficiencies in vitamin B9 and B12 have a higher abortion rate. Also if a bowel obstruction occurs during pregnancy, it is not possible to do a CT scan and very difficult to operate when the patient is pregnant.

Polycystic ovarian syndrome Increased BMI is associated with hormonal imbalance, irregular menstrual cycle, low ovulation or anovulation. PCOS rate is reported to be up to 36% of women before surgery and after bariatric surgery there is about 96% improvement. *Bariatric surgery may be beneficial to restore endocrine equilibrium and irregular menstruation. PCOS may affect 5-10% of women in their reproductive age group, characterised by hyperandrogenism, anovulation and multiple cysts in the ovaries. PCOS is one of the leading causes of infertility in women. It is an endocrinological disorder and may be related to or aggravated by obesity with increase production of adipokines (TNF, leptin), decrease sex hormone binding globulin (SHBG) and insulin resistance (hyperinsulineamia leads to increased ovarian androgen secretion). Some studies showed that losing 5% of body weight in the obese PCOS population may help restore ovulatory cycles and spontaneous conception. With adequate weight loss there can be significant improvements in menstrual dysfunction, hirsutism and obesity/PCOS related co-morbidities (HPT, T2DM, dyslipidaemia). Bariatric surgery have been shown to improve the abnormal sex hormone axis by *Decrease in dehydroepiandrosterone, oestradiol and anti Mullerian hormone *Increase in sex hormone binding globulin Bariatric surgery has been shown to reduce gestational DM and pregnancy related HPT. *Reduction in antepartum pregnancy related complications is likely due to weight loss and the metabolic improvements. *Reduction in labour complications such as obstructed labour (higher Caesarean section rates), anal sphincter injury and post partum haemorrhage. There are no standard guidelines but most surgeons and physicians recommend a 12 to 18 months interval after bariatric surgery before conceiving. However please note however *Some studies have shown that a shorter interval time (< 1 year) have similar maternal/perinatal outcomes compare to those who conceive 1 year after bariatric surgery. *Some studies suggest that pregnancy less than 18months post op may have a higher anaemia and Caesarean section rates.

Metabolic and bariatric surgery   More than half of all metabolic bariatric procedures are performed in women in the reproductive age group *As a result the number of pregnancies after bariatric surgery has also increased in recent years *These patients are still at higher risk than the general population (normal or lower BMI) to develop gestational DM   Metabolic and bariatric surgery often improves fertility in women resulting in more spontaneous or planned conception after surgery *Weight loss reduces obesity related pregnancy risk such as HPT in pregnancy, gestational diabetes (for the current and subsequent pregnancies), large for gestational age (macrosomia), issues with labour/delivery, congenital defects, neonatal hypoglycaemia, intra uterine fetal death *However pregnancy after bariatric surgery (especially gastric bypass) has an increased risk of micronutrients deficiency *The risk (for pregnant ladies after bariatric surgery) for small for gestational age, lower neonatal birth weight and pre-term delivery is also known and should be closely monitored by the obstetrician     In general it is recommended to postpone pregnancy until weight loss stabilizes, typically 1 year after surgery *To allow time for maximal weight loss and making positive lifestyle changes *To reduce the risk for nutritional deficiencies which may have a negative impact on the foetal development and maternal health   Nutrient needs often increase during pregnancy as the foetus grows and maternal blood volume increases   It is important that all patients have an early consult with the obstetrician, GP and dietitian for a tailored individual approach to antenatal blood test and adequate nutritional supplements

Bariatric surgery and pregnancy

Younger female patients should sought proper contraceptive advice from their GP or obstetrician after undergoing bariatric surgery. There may be reduced effectiveness of oral contraceptive pills, weight gain side effects of certain hormonal treatment and consideration for the use of implants or intra uterine devices.

The timing of pregnancy after bariatric surgery is not determined, some recommend waiting 12-24 months

• However the focus should be based on individual patients

The Roux Y gastric bypass and some other major bypass procedures may pose a special risk during pregnancy.

• GIT symptoms such as abdominal pain/distension and nausea/vomiting is difficult to distinguish between a post op complication and the usual symptoms of pregnancy (morning sickness, hyperemesis gravidarum)
• Imaging test such as abdominal CT is contra-indicated.
• Bariatric related surgical complications such as small bowel obstruction, internal hernia, intussusception/volvulus may have a disastrous outcome in the maternal and fetal group.

Screening for gestational diabetes is important. Obese patients even after successful weight loss surgery still have a higher risk to develop gestational diabetes compare to normal weight individuals.

• OGTT may be unreliable and intolerable after bariatric surgery.

As a result of bariatric surgery and patient dietary changes, there is the potential for micronutrient deficiency. Pregnancy related nausea and vomiting or food intolerances may exacerbate the issue.

Meta analysis shows that vitamin A, B1, B6, B12, C, D, K, iron, calcium, zinc, selenium and phosphorus levels in pregnant women after bariatric surgery may be significantly reduced.

• Please note vitamin A has potential teratogenic effects and the levels should be checked and supplementation reduced if necessary.

Adequate nutrition, vitamin and mineral supplements is the most crucial from 10 weeks prior to gestation to 14 weeks after gestation, the most crucial period for the embryo development.

Clinicians can measure maternal gestational weight gain of the mother, antenatal blood test for micronutrient deficiencies and for fetal birth weight.

• It is important to observe for intrauterine fetal growth retardation, small for gestational age and neurological development. There may be a slightly higher risk for preterm labour.

Gestational diabetes   Maternal obesity is a well established risk factor for development of gestational DM and associated complications such as macrosomia, shoulder dystocia, childhood obesity and maternal T2DM   For patients who didn’t have bariatric surgery, the recommendation is to have an oral glucose tolerance test between 24 to 28th week gestation, the gold standard to diagnose gestational DM   OGTT is difficult to do after bariatric surgery (especially gastric bypass) which may lead to dumping syndrome and reactive hypoglycaemia (a higher chance of false negatives)   Note even pregnant mothers (without bariatric surgery) may develop relative hypoglycaemia with glucose levels 20% lower than non pregnant ladies *The risk of OGTT may be up to 60% after bariatric surgery   After bariatric surgery some obstetrician recommend self monitoring fasting and 2 hour post prandial blood glucose monitoring for 1 week during the 24-28th week period *The diagnosis is made is >20% BSL values exceeds threshold, fasting BSL >5.3mmol/L, 1 hour BSL >7.7mmol/L and 2 hours >6.6mmol/L *HbA1C can be used to measure glycaemic control as well   CGM (continuous glucose monitoring using interstitial fluid) after gastric bypass is reliable to check for glucose variability and rapid glycaemic shifts, although this is not used to screen for gestational DM *May over diagnose patients for gestational DM

Special mention for pregnant ladies after bariatric surgery   Higher doses of folic acid may be needed such as 4-5g a day Iron and vitamin B12 replacement is almost routinely given Calcium and vitamin D supplements >50nmol/L is recommended Caution with vitamin A (retinol) supplement because it may be potentially teratogenic   Fetal growth monitoring with ultrasound at 28, 32 and 36 weeks is a minimum Blood tests such as HbA1C is performed instead of OGTT     Please note: Regular over the counter vitamin supplements are not likely to be sufficient *Specialised post op bariatric multivitamin supplements are sometimes recommended especially for deficiencies in iron, folate, B12 and vitamin D *Note that high levels of folic acid may also mask vitamin B12 deficiency, which is also important in the foetal neurological development *Vomiting during pregnancy is associated with thiamine (B1) deficiency *Foods high in vitamin A or retinol based (A) supplements should be avoided in pregnant women to avoid vitamin A toxicity but at the same time vitamin A deficiency should be avoided (Beta carotene is recommended)

Nutritional issues   Macronutrients during pregnancy   During pregnancy the protein demands increases as well The daily recommended protein intake is 46g (0.8mg/kg ideal body weight) during the first trimester and 71g (1.1g/kg) during the second and third trimester   After bariatric and metabolic surgery, the protein intake should be about 60g (1.5g/kg ideal body weight)       Micronutrient deficiencies to consider: Folate deficiencies can cause neural tube defects, preterm labour and placenta related complications Vitamin B9 and B12 deficiencies are associated with a higher risk for abortion and preterm labour Vitamin B1 deficiency may cause cardiac and neurological complications Vitamin C, E, iron, selenium and zinc deficiency are associated with preterm birth   Vitamin A deficiency can lead to intrauterine growth retardation, retinal damage and childhood blindness *But retinol vitamin A is considered teratogenic *Hence the beta carotene form is recommended   The normal post bariatric multi vitamin supplements often has retinol Hence a substitute to pregnancy supplements are needed     The micronutrient requirements during pregnancy recommendation can vary, usually the daily recommendations are: *Folic acid 0.4-1mg *Iron 45-60mg *Thiamine (B1) >12mg *Beta carotene (A) 5000 IU *Vitamin E 15mg *Zinc 15mg *Copper 2mg *Selenium 50 micro gram

Short summary on deficiencies and consequences Vitamin A                  visual impairment Vitamin K                   intra cranial ahemorrhage Vitamin B12              neural developments Vitamin B9 (folate)  neural tube defects