Screening for Placental Insufficiency in High-risk Pregnancies: Is Earlier Better?

Costa, S.L.; Proctor, L.; Dodd, J.M.; Toal, M.; Okun, N.; Johnson, J.-A.; Windrim, R.; Kingdom, J.C.P.

doi:10.1016/j.placenta.2008.09.004

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Volume 29, Issue 12 , Pages 1034-1040, December 2008

Screening for Placental Insufficiency in High-risk Pregnancies: Is Earlier Better?

S.L. Costa
- Department of Obstetrics and Gynecology, Mount Sinai Hospital, University of Toronto, Ontario, Canada
L. Proctor
- Department of Obstetrics and Gynecology, Mount Sinai Hospital, University of Toronto, Ontario, Canada
J.M. Dodd
- Department of Obstetrics and Gynecology, Mount Sinai Hospital, University of Toronto, Ontario, Canada
- Discipline of Obstetrics and Gynecology, The University of Adelaide, Adelaide, South Australia, Australia
M. Toal
- Department of Obstetrics and Gynecology, Mount Sinai Hospital, University of Toronto, Ontario, Canada
N. Okun
- Department of Obstetrics and Gynecology, Mount Sinai Hospital, University of Toronto, Ontario, Canada
J.-A. Johnson
- Department of Obstetrics and Gynecology, University of Calgary, Alberta, Canada
R. Windrim
- Department of Obstetrics and Gynecology, Mount Sinai Hospital, University of Toronto, Ontario, Canada
J.C.P. Kingdom
- Department of Obstetrics and Gynecology, Mount Sinai Hospital, University of Toronto, Ontario, Canada
- Department of Medical Imaging, Mount Sinai Hospital, University of Toronto, Ontario, Canada
- Corresponding author. Department of Obstetrics and Gynecology, Mount Sinai Hospital, University of Toronto, 600 University Avenue, Toronto, ON M5G 1X5, Canada. Tel.: +1 416 586 8764; fax: +1 416 586 8565.

Accepted 5 September 2008. published online 20 October 2008.

Abstract

Objective

To compare a profile of placental function between the first and second trimesters in pregnancies at high risk of adverse perinatal outcomes attributable to placental insufficiency.

Study design

Prospective cohort study in 61 singleton pregnancies. Uterine artery Doppler and placental morphology (shape and texture) were determined at 11–13⁺⁶ weeks and at 18–23⁺⁶ weeks. First trimester (pregnancy-associated placental protein-A [PAPP-A]) and second trimester (total hCG and alpha fetoprotein [AFP]) serum biochemistry were determined. The two screening periods were compared for the prediction of a range of severe adverse perinatal outcomes (intrauterine growth restriction [IUGR], abruption, severe pre-eclampsia/HELLP syndrome, delivery<32 weeks, or stillbirth).

Results

Adverse perinatal outcomes occurred in 14 (23%) women; 3 (4.9%) losses<20 weeks, 2 (3.3%) stillbirths>20 weeks, 4 (6.6%) IUGR, 7 (11.5%) severe pre-eclampsia/HELLP syndrome, and 10 (16.4%) deliveries<32 weeks. Abnormal second trimester placental morphology was significantly associated with adverse outcome [+LR: 3.6, 95% CI: 1.3–8.5; −LR: 0.63, 95% CI: 0.36–0.93; p=0.025], as was ≥1 abnormal second trimester tests [+LR: 5.9, 95% CI: 1.6–24; −LR: 0.68, 95% CI: 0.59–0.89; p=0.005] or ≥2 abnormal second trimester tests [+LR: 3.6, 95% CI: 1.3–7.7; −LR: 0.58, 95% CI: 0.27–0.94; p=0.035]. No combination of first trimester tests significantly predicted severe adverse perinatal outcomes. A study sample size of 822 women with similar high-risk characteristics would be needed in order to refute the conclusion that present methods of first trimester screening are not inferior to second trimester screening for severe placental insufficiency (p=0.05, power 80%, z-test).

Conclusions

In clinically high-risk pregnancies, prediction of adverse perinatal outcomes using placental function testing is more effective in the second compared with the first trimester.

Keywords: Maternal serum screening, First and second trimesters, Uterine artery Doppler, Placental morphology, Adverse perinatal outcome, Placental pathology