Background: Small for gestational age (SGA) babies are more common in women with antiphospholipid antibodies but data are limited about the prevalence of antiphospholipid antibodies in women who have delivered SGA babies.
Aim: To determine whether elevated levels of anticardiolipin, antiphosphatidyl serine and/or antiß2 glycoprotein I antibodies are more common in normotensive women who delivered SGA babies compared with women who delivered appropriate for gestational age babies.
Methods: Case–control study. Cases were normotensive women who delivered an SGA baby (birthweight <10th%) without chromosomal or congenital abnormality. Controls were healthy women who delivered a baby at term with birthweight >10th percentage.
Results: A total of 137 women with SGA pregnancies and 290 controls had antiphospholipid antibodies measured. The prevalence of anticardiolipin and antiß2 glycoprotein I antibodies did not differ between SGA cases and controls. Antiphosphatidyl serine IgG antibodies were more common in women with SGA pregnancies than controls seven (5%) versus five (1.7%), relative risk (RR) 1.84 (1.12–3.03). There was no difference in the prevalence of ‘any antiphospholipid antibodies’ between SGA 10 (7.2%) and controls 16 (5.6%). There was a trend to more abnormal umbilical Doppler studies in SGA pregnancies with positive antiphospholipid antibodies three (50%) versus 19 (24%), RR 2.9 (0.62–13).
Conclusions: Antiphospholipid antibodies were uncommon in this cohort of SGA pregnancies. Further studies are needed in SGA pregnancies with abnormal umbilical Doppler studies to determine if screening for antiphospholipid antibodies is worthwhile in this severe subgroup.