Why we succeed and fail in detecting fetal growth restriction: A population-based study

INTRODUCTION: The objective of this study was to explore the association between detection of fetal growth restriction and maternal-, health care provider- and organizational factors.

MATERIAL AND METHODS: A historical, observational, multicentre study. All women who gave birth to a child with a birth weight less than the 2.3rd centile from September 1, 2012 to August 31 2015 in Zealand, Denmark were included. The population was identified through the Danish Fetal Medicine Database. Medical charts were reviewed to obtain data regarding maternal characteristics and information on the health care professionals. Date of authorization for the midwives and obstetricians involved was extracted from the Danish Health Authorizations Registry. Multivariable Cox-regression models were used to identify predictors of antenatal detection of fetal growth restriction , and analyses were adjusted for hospital, body mass index, parity, the presence of at least one risk factor and experience of the first midwife, number of midwife visits, number of visits to a doctor, the experience of the consultant midwife or the educational level of the doctor, the number of scans and gaps in continuity of midwife-care. Antenatal detection was defined as an ultrasound estimated fetal weight less than the 2.3rd centile (corresponding to -2 standard deviations) prior to delivery.

RESULTS: Among 78,544 pregnancies, 3,069 (3.9%) were fetal growth restriction. Detection occurred in 31% of fetal growth restriction -pregnancies. Clinical experience (defined as years since graduation) of the first consultation midwife was positively associated with detection, hazard ratio 1.15 (95% CI 1.03 - 1.28), for every 10 years of additional experience. The hazard of detection increased with the number of midwife consultations, hazard ratio 1.15 (95% CI 1.05 - 1.26), and with multiparity, hazard ratio 1.28 (95% CI 1.03 - 1.58). After adjusting for all covariates an unexplained difference between hospitals (p=0.01) remained.

CONCLUSIONS: The low risk nullipara may constitute an overlooked group of women at increased risk of antenatal non-detection of fetal growth restriction. Being screened by experienced midwives during early pregnancy and having access to multiple midwife consultations may improve future diagnosis.