Pregnancy after bariatric surgery — structured oral station (12 minutes)

Opening prompt — "Build the booking plan."

Model response — say it in this order: [1][3]

• "Procedure type predicts the complication — a Roux-en-Y bypass is restrictive plus malabsorptive, so I expect internal hernia, dumping and micronutrient deficiency. She is two years out, so the conception interval is acceptable."
• "The booking plan has four pillars: nutritional supplementation at post-bariatric doses, a glucose strategy that avoids the OGTT, serial growth ultrasound for SGA, and a documented plan for the third-trimester acute abdomen."
• "I would take a nutritional blood panel — full blood count, iron studies, B12, folate, 25-hydroxyvitamin D, calcium, vitamin A, PTH, INR — and repeat it every trimester."[3]

Probe 1 — "She takes a standard prenatal vitamin. What do you change?"

• "Standard prenatal vitamins do not meet post-bariatric requirements — she needs two to three times the routine doses."[3]
• "Iron 45 to 60 mg elemental daily, vitamin B12 1 mg orally daily or 1000 micrograms intramuscularly every 12 weeks, folic acid up to 1 mg, vitamin D 1000 IU standard rising to 3000 to 6000 IU if deficient targeting 50 nmol/L, and calcium 1000 to 2000 mg daily."[3]
• "I would start B12 before folic acid, because folic acid can mask the haematological signs of B12 deficiency."

Probe 2 — "How will you screen her for gestational diabetes?"

• "The 75 g OGTT is contraindicated after a Roux-en-Y bypass — it provokes dumping and reactive hypoglycaemia. The OEGGG consensus is explicit on this."[2]
• "I would measure HbA1c at the start of pregnancy and perform home glucose monitoring — fasting and one- to two-hour postprandial — between 24 and 28 weeks."[3]
• "I would diagnose GDM by the IADPSG thresholds on home glucose: fasting 5.1 mmol/L or above, or one-hour postprandial 7.0 mmol/L or above, on two occasions."

Probe 3 — "She is 34 weeks and phones with postprandial colicky upper abdominal pain and vomiting. What is your concern?"

• "My concern is internal hernia with small bowel obstruction. Postprandial colicky pain in the third trimester after bypass is hernia until proven otherwise — not hyperemesis, not round-ligament pain."[4]
• "I would ask her to come in immediately, resuscitate the mother first — NPO, intravenous fluids, nasogastric tube if vomiting, correct electrolytes, fetal monitoring as the maternal state allows — and call the surgical team now."[4]
• "Imaging: ultrasound first, CT abdomen with contrast if she is stable. But imaging does not delay surgical assessment — a high-risk post-bypass woman with obstruction signs goes to theatre regardless of a negative scan."[4]

Probe 4 — "The surgeon wants to know your operative preference."

• "Laparoscopy is the preferred approach in pregnancy after bypass. The Deleus 10-year series of 32 pregnant women operated for small bowel obstruction after bypass showed laparoscopic exploration was suitable, with no maternal or fetal deaths and no ischaemia-related bowel resections, and a median gestational age at delivery of 39 weeks."[4]
• "Reduce the hernia and close the mesenteric defect. Maternal resuscitation takes priority over fetal concerns in the acute phase."

Probe 5 — "She asks whether she can have a normal birth and breastfeed."

• "Yes — bariatric surgery is not a contraindication to vaginal delivery. Caesarean is for standard obstetric indications. Epidural is not contraindicated, though it may be technically harder if obesity persists; ultrasound guidance helps."[3]
• "Breastfeeding is encouraged. I would continue her supplements through lactation, because supply may be reduced — I would monitor the infant's weight and involve a lactation consultant."[3]
• "At the postnatal visit I would discuss contraception — a long-acting reversible method that does not depend on gut absorption, such as a subdermal implant or levonorgestrel IUD, because oestrogen-containing options raise VTE risk and may be unreliable after bypass. Only 9% of women received such counselling in the Goldenshluger survey, and 33% of pregnancies were unintended."[5]