Screening for pre-eclampsia and fetal growth restriction in twin pregnancies at 23 weeks of gestation by transvaginal uterine artery Doppler.

OBJECTIVE: To assess the value of transvaginal uterine artery Doppler at 23 weeks of gestation in predicting the development of adverse perinatal outcomes in twin pregnancies. PATIENTS AND METHODS: Women with twin pregnancies attending for routine ultrasound examination at 23 weeks in any one of seven hospitals underwent Doppler assessment of the uterine arteries. The right and left uterine arteries were identified using color flow mapping and velocity waveforms were obtained using pulsed Doppler. The mean pulsatility index (PI) of the two arteries was determined and the presence of uterine artery notching noted. Results were compared between monochorionic and dichorionic twins, and with our previously reported data from singleton pregnancies. Screening characteristics in the prediction of pre-eclampsia, fetal growth restriction (FGR), placental abruption, fetal death and early preterm delivery were calculated. RESULTS: Uterine artery Doppler at 22-24 weeks of gestation was performed in 360 twin pregnancies, including 324 dichorionic and 36 monochorionic diamniotic twins. Complete outcome data were available in 351 (97.5%). The mean uterine artery PI did not change significantly with gestation and there was no significant difference in mean PI between the dichorionic and monochorionic groups. However, the mean PI was significantly lower in twin pregnancies than in singletons. The pregnancy was complicated by pre-eclampsia in 6.0% of cases, FGR below the 5th centile of both twins in 8.8%, abruption in 0.9%, intrauterine fetal death in 1.7% and early preterm delivery at less than 32 completed weeks of gestation in 5.7% of cases. The respective sensitivities of uterine artery mean PI above the 95th centile for these complications were 33.3%, 9.7%, 66.6%, 33.3% and 18.6%. CONCLUSIONS: In twin pregnancies PI in the uterine arteries is lower than that in singleton pregnancies, but there is no significant difference between dichorionic and monochorionic twins. Doppler assessment of the uterine arteries at 23 weeks identifies a large proportion of twin pregnancies destined to develop adverse outcomes related to uteroplacental insufficiency.

First-trimester maternal serum levels of placenta growth factor as predictor of preeclampsia and fetal growth restriction.

OBJECTIVE: To determine whether the reported decrease in maternal serum placenta growth factor concentration in preeclampsia is evident from the first trimester and before clinical onset of the disease. We also examined levels in pregnancies that subsequently resulted in fetal growth restriction (FGR). METHODS: Placenta growth factor concentration was measured in stored maternal serum samples obtained at 11-14 weeks of gestation from 131 women who subsequently developed preeclampsia, 137 women who subsequently developed FGR, and 400 randomly selected controls who did not develop preeclampsia or FGR. Preeclampsia was defined as diastolic blood pressure of 90 mmHg or more on two occasions 4 hours apart, accompanied by proteinuria (more than 300 mg of total protein in a 24-hour urine collection or a positive test for albumin on reagent strip) in women with no pre-existing hypertensive or renal disease. Fetal growth restriction was considered present if a woman subsequently delivered a live infant with a birth weight below the fifth centile for gestation. RESULTS: In the control group, maternal serum placenta growth factor concentration increased with gestation. Compared with the controls (median multiple of the median 0.98, standard deviation [SD] 0.51), levels in the preeclampsia group (median multiple of the median 1.09, SD 0.52) were not significantly different (t = 1.83, P = .07), but in the FGR group (median multiple of the median 1.57, SD 0.74), levels were significantly increased (t = 10.85, P < .001). CONCLUSION: The previously reported decrease in serum placenta growth factor levels in women with preeclampsia might not precede clinical onset of the disease and is not apparent in the first trimester of pregnancy. Levels are significantly increased in pregnancies resulting in FGR.