Information sharing and communication in management of large for gestational age babies in non-diabetic mothers

M R C O G PA R T 2 · S O S P O C K E T C A R D · K N O W L E D G E A R E A 5 – A N T E N ATA L C A R E

Large for Gestational Age Babies in Non-Diabetic Mothers: Information Sharing & Communication Kahlon G, Relph S, Yoong W. Information sharing and communication in management of large for gestational age babies in non-diabetic mothers. TOG 2023;25:282–90. doi:10.1111/tog.12894

~10% 43.9% 3695 BABIES IN ENGLAND >4000 G EFW OVERESTIMATED (ZAFMAN) ELECTIVE CS TO PREVENT 1 BPI

DO N' T-M IS S FA C TS

1. No specific UK guideline for LGA in non-diabetic women — be explicit about uncertainty. NICE LGA = >95th centile; RCOG macrosomia = >4500 g

2. SFH >2 cm greater than expected → consider USS for fetal size/wellbeing (NICE antenatal care)

3. EFW is overestimated in 43.9% (Zafman) — never intervene on EFW alone; predictive value best within 10 days of delivery

4. EFW predicts shoulder dystocia in only 22% of cases; 48% of shoulder dystocia babies weigh <4000 g

5. Cochrane 2023: IOL 37–40 weeks ↓fractures (RR 0.20, NNT 60) and ↓shoulder dystocia, no ↑CS, but ↑3rd/4th degree tears

6. 3695 elective CS to prevent one permanent BPI (non-diabetic, EFW >4500 g) vs 443 if diabetic

7. Offer discussion of all three options — expectant management, IOL, caesarean (NICE inducing labour 1.2.24); recommend consultant-led labour ward

8. Montgomery: disclose any risk a reasonable person in the patient’s position would attach significance to; use BRAIN or iDECIDE to structure the discussion

SCREENING TEST SENSITIVITY

SFH for LGA 76% · for macrosomia 30% USS EFW >4000 g 67.5% (LR+ 6.58) AC >36 cm 57.8%

EFW for shoulder dystocia 22%

NUMBERS TO QUOTE

~10% of babies in England >4000 g; ~52% of shoulder dystocia occurs above 4000 g Grade III HIE after shoulder dystocia in a >4000 g baby: 0.037% (HSIB, 22/31 cases) Boulvain: shoulder dystocia 8 vs 25, RR 0.32 (0.15–0.71)

Big Baby Trial: IOL 38+0–38+4 vs expectant, EFW >90th centile customised

ABBREVIATION KEY

LGA — large for gestational age CS — caesarean section/birth

SGA — small for gestational age PPH — postpartum haemorrhage

EFW — estimated fetal weight BPI — brachial plexus injury

SFH — symphysio-fundal height HIE — hypoxic ischaemic encephalopathy

USS — ultrasound scan HSIB — Healthcare Safety Investigation Branch

IOL — induction of labour GAP/GROW — growth assessment protocol / gestation related optimal weight AC / HC / FL / BPD — abdominal circumference / head GMC — General Medical Council circumference / femur length / biparietal diameter RR / OR / CI — relative risk / odds ratio / confidence interval OGTT — oral glucose tolerance test

Source: The Obstetrician & Gynaecologist (TOG), RCOG journal — non-diabetic mothers. TOG 2023;25:282–90. doi:10.1111/tog.12894

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