Birth weight in pre-eclamptic and normotensive twin pregnancies: an analysis of discordance and growth restriction.
The aim of this study was to verify whether twin pregnancies complicated by pre-eclampsia were associated with a higher rate of inter-twin weight discordance or an increased prevalence of small for gestational age (SGA) neonates than in normotensive twin pregnancies. A 17 year retrospective study was undertaken by examining 76 twin pregnancies complicated by pre-eclampsia and comparing them with 400 normotensive twin pregnancies. The case notes were reviewed in reference to birth weight differences, birth order, pregnancy outcome and inter-twin birth weight discordance. Statistical analyses were performed with t-test, contingency tables, regression curves, rank sum test and non-parametric survival plots. Power analysis was also carried out. Pre-eclamptic twin pregnancies were delivered at similar weeks of gestation to normotensive. They resulted in a smaller size for the second twin the earlier the delivery week, while in normotensive twin pregnancies no significant difference occurred at any week. Twin pregnancies complicated by pre-eclampsia showed higher rates of SGA neonates among second twins than those with normal pressure. The >25% discordance was associated with lower gestational age at delivery in each group [mean (range) 33 weeks (27-38) versus 37 (29-41), P < 0.005 pre-eclampsia and 35 weeks (25-41) versus 38 (25-42), P < 0.001 normotensive]. In pre-eclampsia the concomitant occurrence of SGA second twin and the discordance >25% was associated with shorter gestation while the presence of SGA second twin alone was not.
Ferrazzani
S
S
Department of Obstetrics and Gynaecology, Catholic University, School of Medicine, 00168 Rome, Italy.
Merola
A
A
De Carolis
S
S
Carducci
B
B
Paradisi
G
G
Caruso
A
A
D000328:Adult; D001722:Birth Order; D001724:Birth Weight; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age; D011225:Pre-Eclampsia / Q000150:complications*; D011247:Pregnancy; D011256:Pregnancy Outcome; D012044:Regression Analysis; D012189:Retrospective Studies; D014427:Twins