Customised symphysio fundal height charts.

OBJECTIVES To evaluate the feasibility, applicability and the value of customised symphysio fundal height (SFH) charts developed for women of Indian origin in the United Kingdom (UK: CSFH - In chart) and women of African origin in the UK (CSFH - Af chart) in detecting fetal growth restriction and predicting low birth weight (LBW) of the neonate in a Lankan population, and to compare these results with the results obtained from the SFH chart currently used in Sri Lanka (FHB chart) and another SFH chart which uses a range of plus or minus 2-3 cm of the value of the gestational age in weeks as the reference range (GA ± 2 to 3 cm chart). METHODS Pregnant women (n = 416) with confirmed periods of gestation (POG) of <22 weeks and having a singleton fetus and with no obstetric complications, had their age, parity, POG and Body Mass Index (BMI) documented. Their SFH were measured at four weekly, fortnightly and weekly intervals between 20 - 28, 28 - 36 and 37 - 41 weeks respectively and plotted on the CSFH - In chart, CSFH - Af chart, FHB chart and the GA ± 2 to 3 cm chart. The gestational age at delivery and the birth weight were recorded. Pre term deliveries were excluded leaving 401 participants for analysis. RESULTS There were 164 (39.4 %) primigravidae, 76 (18.9 %) had low BMI and 71 (17.7 %) had a high BMI. Maternal BMI at booking was positively correlated to the birth weight of the baby but not the parity. In detecting LBW at term, the CSFH - In chart had the best sensitivity, specificity, positive predictive value, negative predictive value, and the likelihood ratios. Of the two non customised charts the GA ± 2 to 3 cm chart was better than the FHB chart. CONCLUSIONS Until a customised SFH chart is developed for Sri Lanka, the CSFH - In chart or the GA ± 2 to 3 cm chart should be used for antenatal monitoring of fetal growth.