PP029. Gestational hypertension and birth weight in twin pregnancies.

Introduction: It is well known that hypertensive disorders of pregnancy are most frequent in twin pregnancies than in singleton ones. As demonstrated by a previous work of our group, twin pregnancies complicated by preeclampsia are associated with a higher rate of “small for gestational age” (SGA) neonates and inter-twin weight discordance than normotensive ones. Objectives: The present study investigates the effect of gestational hypertension (GH) on neonatal birth weight, inter-twin weight discordance and growth restriction rate among twin pregnancies. Methods: A 26 year retrospective study was undertaken by examining 196 twin pregnancies complicated by GH, from January 1, 1980 to December 31, 2006, and comparing them to 912 normotensive twin pregnancies. Results: No significant differences were observed between the two groups in relationship to birth weight, inter-twin weight discordance and growth restriction rate, with a trend towards a higher birth weight in GH group. In normotensive group, the discordance >25% was associated with a lower gestational age at the delivery (p <0.00001). Moreover, the rate of pregnancies with SGA second twin gradually rose while paralleling the degree of discordance. Conclusion: Contrary to preeclampsia in twin pregnancies the outcome of those complicated by GH is similar to normotensive ones. The trend towards a higher birth weight in GH seems apparently paradoxical, but it may reflect the role of uncomplicated hypertension in twin pregnancies: the increased blood pressure could be a physiologic response for more blood nutrient supply to the fetuses. [Copyright &y& Elsevier]