Key points are not available for this paper at this time.
OBJECTIVE: This study aims to evaluate the distribution of mean arterial pressure (MAP) and uterine artery Doppler pulsatility index (PI) in first trimester twins with and without preeclampsia. METHOD: A total of 147 twins were recruited from a specialist clinic and 110 unaffected singleton pregnancies attending the same institution served as controls. MAP and Doppler PI values were expressed in multiples of the gestation-specific median using published equations. RESULTS: Among the twins, 12 had preeclampsia and two had pregnancy-induced hypertension. Among unaffected pregnancies, there was no significant difference in MAP levels between twins and singletons (P = 0.17, Wilcoxon rank sum test, two-tail). However, the Doppler PI levels were highly statistically significantly lower than in singletons (P < 0.0005). MAP was unrelated to chorionicity (P = 0.46), but there was a statistically significant increase in Doppler PI among monochorionic compared with dichorionic twins (P < 0.01). In twins with preeclampsia, MAP was significantly higher than in unaffected twins (P < 0.02, one-tail), whereas Doppler PI levels were significantly reduced (P < 0.01, two-tail). CONCLUSION: If first trimester screening for preeclampsia is extended to twins, a different normal median Doppler PI equation will be needed. Contrary to expectations, Doppler PI levels may not be raised in affected twins, although this needs confirmation in a larger study.
Svirsky et al. (Tue,) studied this question.