Birthweight in pregnant women with protein S deficiency treated with low-molecular-weight heparin: a retrospective cohort study.

OBJECTIVE

To determine the risk of small-for-gestational-age (SGA) and intrauterine growth retardation (IUGR) in pregnant women with protein S (PS) deficiency who received low-molecular-weight heparin (LMWH).

METHODS

Retrospective cohort study of pregnant women seen from January 2002 to December 2011. The study cohort comprised a total of 328 patients with PS deficiency, who received prophylactic enoxaparin during pregnancy. The control cohort included 11 884 pregnant women without significant past medical history. The risk of SGA and IUGR was calculated as odds ratio. Multivariate regression analysis over the entire reference population was performed determining the risk of both SGA and IUGR by adjusting for maternal age, first delivery, maternal underweight status, pre-eclampsia, other treated thrombophilias or history of recurrent abortion.

RESULTS

The SGA rates in the PS deficiency and control cohorts were 10.7% and 8.5%, respectively (p > 0.05). There was no increased risk of SGA (unadjusted OR = 1.28, 95% confidence interval [CI] 0.9-1.83; adjusted OR = 1.35, 95% CI 0.91-2.01). The IUGR rate was 2.7% in pregnant women with PS deficiency versus 4.1% in the control group (p > 0.05). Also, we did not find a significant risk of IUGR (OR = 0.66; 95% CI 0.34-1.28; adjusted OR = 0.843; 95% CI 0.42-1.70).

CONCLUSIONS

In women with PS deficiency treated with LMWH, the risk of SGA and IUGR is similar to the one found in healthy pregnant women.