Obese Maternity Woman: Management of

• Purpose

• Definition of obesity

• Pregnancy risks associated with obesity

• Management

• Occupational Health and Safety issues

• Consumer fact sheet: Obesity and Pregnancy
  

• References

Purpose

• early intervention is essential

• acknowledge that all modalities of care for these women are more complicated

• there is increased maternal morbidity and mortality while pregnant and especially in labour

• extra equipment, facilities and staff are required

Definition of obesity

Pregnancy risks associated with obesity

Risks include:

• Gestational diabetes

• Hypertension, pre-eclampsia

• abnormal fetal growth: either macrosomia or intra uterine growth restriction

• sleep apnoea

• undiagnosed fetal anomaly

• failure to progress in labour

• shoulder dystocia

• difficulties monitoring fetal heart

• inadequate analgesia

• unsuccessful vaginal birth after caesarean section

• emergency caesarean section

• technically difficult Caesarean section, with associated increased morbidity and mortality

• wound infections post operative delivery

• thrombo-embolic events

• postnatal depression

• increased maternal risk of morbidity and death for both mother and baby

• elective surgery in the obese patient is high risk

• emergency surgery is extremely high risk

• patient positioning (since patient cannot lie flat)

• regional anaesthesia for surgery favoured but more difficult to site, unpredictable spread of local anaesthetics, more likely to dislodge or fail

• airway maintenance difficult, intubation may be impossible especially in the emergency setting

• oxygenation difficult due to abdominal pressure

• non-invasive BP (NIBP) cuffs unreliable, may require intra-arterial monitoring

• need for extra resources (staffing & equipment) continues into the post-operative period. High dependency and/or intensive care nursing may be needed, which may require emergency transfer to another hospital.

• In addition, issues such as positioning and moving of the patient, and the safe use of equipment, such as lithotomy stirrups, operating tables etc, needs to be considered.

Management

• All women classified as Obese II or above (i.e. BMI > 35) must be referred to the MFM clinic for antenatal management.

• An early Glucose Tolerance Test (GTT) for the detection of pre-existing type II diabetes may be considered, and if normal or not done, all women have the recommended Glucose Challenge Test (GCT) at 26 weeks to check the development of gestational diabetes.

• All women should be offered the opportunity to consult with a dietitian.

• Medical issues related to the obesity (as outlined above) need to be discussed with the woman, and documented. This is often a difficult issue for women to discuss, and must be handled with compassion and respect. It is however important that these issues are not neglected due to discomfort on the part of the woman or staff.

• Where possible, midtrimester fetal morphological assessment should be performed at 20-21 weeks, rather than 18-20 weeks, and the presence of obesity should be noted on the ultrasound request form.

• A repeat scan for fetal weight, liquor volume and umbilical artery doppler studies in the third trimester (28-34 weeks) may be helpful to assess fetal growth, as it can be difficult to estimate growth from palpation alone in obese women.

• Due to the increased risk of pregnancy complications in this group of women, it is recommended that antenatal visits are scheduled at least fortnightly from 28 weeks, and weekly from 36 weeks. Blood pressure should be checked with an appropriately sized cuff at each visit.

• All women must be referred to the Anaesthetic Assessment Clinic (AAC) for consultation, regardless of the planned mode of delivery. Ideally this will occur between 28-34 weeks for most women. The woman should be re-weighed. If preterm delivery is indicated, or in patients presenting in labour who have not had a pre-labour anaesthetic consultation, the on-call anaesthetic registrar should be paged to organise urgent anaesthetic consultation. Plan to be documented on Anaesthetic Record (MR/43005).

• Booking for caesarean section - weight of 100 kg or more needs to be noted on the booking form and confirm that the woman has been referred to AAC.

• Antenatal thromboprophylaxis is recommended in obese women who require bed rest for any reason.

Anaesthetic management

• If seen in Anaesthetic Assessment Clinic (AAC), discuss risks associated with analgesia (epidurals) and anaesthesia (either regional or general) for peri-partum surgery.

• If woman first presents in labour, early involvement of anaesthetic staff to allow this discussion to take place.

• When a women in this category presents in labour, anaesthetic staff are to be notified immediately.

• The use of intra operative pneumatic compression stockings may be considered for women with multiple risk factors for VTE.

Intrapartum

• Women in the Obese II or above class are at significantly higher risk of operative delivery, including caesarean section, and such operative deliveries carry increased obstetric and anaesthetic risk (see above).

• Where possible, staff should aim for these women to deliver during normal working hours, when a full complement of staff (including consultant anaesthetists) is present in the hospital. This can be facilitated by such measures as ensuring appropriate cervical ripening before labour induction, commencing inductions as a priority in the morning (ideally before the morning handover if possible), and where clinically appropriate planning the timing of progress assessments with consideration to the availability in the hospital of senior staff, should operative delivery be required.

• For women undergoing elective caesarean section, the weight (kg) should be noted on the booking form, to allow theatre staff to have appropriate equipment available (eg hover mats, appropriately rated operating table etc).

• For women presenting to birth suite in labour, or for induction of labour, the obstetric staff should be aware of any documented anaesthetic plan, and in any respect should contact the anaesthetic registrar on for birth suite to inform them of the presence of the woman in birth suite, and their current status. The anaesthetic registrar in turn will take responsibility for notifying their consultant as appropriate, and also for informing theatre staff of the woman, so appropriate theatre equipment can be prepared, in case emergency caesarean section is required.

• Where women are required to have an epidural, birth suite staff must place a deflated hover mat under the woman prior to the insertion of the epidural. Staff should ensure that if an immobilised woman requires moving, that OH&S protocols are adhered to, and that sufficient assistance is available.

• For woman in labour an IV cannula should be inserted early in labour, and a Group & Save and FBE collected.

• There is no specific requirement for continuous fetal monitoring in an otherwise uncomplicated pregnancy, however many of these patients will have other indications for continuous monitoring. Internal fetal monitoring (fetal scalp electrode) should be considered if a satisfactory recording is not obtained by external monitoring.

• There is an increased risk of shoulder dystocia. Midcavity instrumental vaginal deliveries should be discussed with the consultant before being attempted.

• Women in this category may not be able to receive emergency general (and possibly regional) anaesthesia without a minimum of 2 anaesthetists being present. Therefore, some "Code Green" caesarean sections may not be able to commence until all the staff required (including 2 anaesthetists) are present. Whilst this may result in a longer "decision to delivery interval", and pose additional risk to the fetus, the safety of the patient outweighs the duty to the as yet unborn baby. The need for two anaesthetists will be assessed on a case by case basis by the available anaesthetist in the hospital and at the earliest possible stage before a Code Green is called.

Postpartum

• Obese women should be encouraged to breastfeed which may enhance maternal weight loss and reduce the likelihood of childhood obesity in the infant.

• Women should be reassessed before or during labour for risk factors for VTE. Age > 35 yrs and BMI > 30 or weight > 90 kg are important independent risk factors for post partum VTE even after vaginal delivery. The combination of either of these risk factors with any other risk factor for VTE (such as preeclampsia or immobility) should lead the clinician to consider the use of LMWH for 3 to 5 days post partum.

• Obesity increases the risk of thrombo-embolism after birth (irrespective of mode of delivery). Dalteparin sodium (Fragmin) 5000 I/U manè is recommended as the standard regimen of heparin may not be sufficient for obese women. Class 1 TED stockings could also be considered where there are contraindications to the use of heparin or in addition to the fragmin regimen.
  

• Refer to CPG Thromboprophylaxis in women undergoing Caesarean Section.
  
  

Occupational Health and Safety Issues

• where a woman is 100 kg or more, or at staff request a hover mat will be used to assist in the transfer
  

• placement of hover mat prior to epidural procedure is mandatory

• elective caesarean section patients are encouraged to walk to theatre wherever possible

• theatre trolley: 200kg

• birth suite bed (Affinity II™) - safe working load: 170kg
  
  

Consumer fact sheet

References