Obesity and woman in the reproductive age group

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 cyst 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.

Special cautionary note for patients who became pregnant after a 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.

Bariatric surgery and pregnancy

Younger female patients should sough 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 intra uterine devices.

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, 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 and small for gestational age. There may be a slightly higher risk for preterm labour.
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 supplement because it is 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  

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.
  • 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.