IMPACT OF PREECLAMPSIA ON BIRTH OUTCOMES
Xu Xiong, MD, DrPH
Department of Obstetrics and Gynecology Université de Montréal, Quebec, Canada
Preeclampsia
• A syndrome characterized mainly by hypertension and proteinuria after 20 weeks of gestation. • A leading cause of maternal and perinatal morbidity and mortality worldwide. • Unknown etiology and pathogenesis. • No treatment (except early delivery: preterm birth). • No prevention.
IMPACT OF PREECLAMPSIA ON BIRTH OUTCOMES • Preeclampsia is associated with an increased risk of poor fetal growth (e.g., SGA, LBW)
Fig 1. PIH and Low Birth Weight (N=97,270 Alberta, Canada)
50 40 30 20 10 0 Non-PIH GH PE 5,2 10,6 26 LBW(%)
Fig 2. PIH and Preterm birth (N=97,270 Alberta, Canada)
50 40 30 20 10 0 Non-PIH GH PE 7,3 10,1 27,5 Preterm Birth (%)
Fig 3. PIH and Small for Gestational Age (N=97,270 Alberta, Canada)
SGA(%) 10 8 6 4 2 0 Non-PIH GH PE 2,9 5,1 7,4
IMPACT OF PREECLAMPSIA ON BIRTH OUTCOMES
• Preeclampsia is associated with an increased risk of poor fetal growth (SGA, LBW) • Preeclampsia is associated with an excessive fetal growth (LGA, HBW)
Fig 4. Preeclampsia & High Birth Weight (>4000 g) (N=14,461, Suzhou, China, 1989-1990)
10 High birth weight (%) 8 6 4 2 0 Non-PIH GH PE Severe PE 3,1 3,8 4,3
3,7
Fig 5. PIH and High Birth Weight (>4200 g)
(N=97,270 Alberta, Canada)
10 8 5,6 6 4 2 0 Non-PIH GH PE 7,3 5 High birth weight (%)
Fig 6. PIH and Large for Gestational Age (N=97,270 Alberta, Canada)
10 8 6 4 2 0 Non-PIH GH PE 2,2 4,5 4,7 LGA (%)
Preeclampsia and fetal growth
(Xiong et al, Am J Obstet Gynecol 1999;180:207-13) (Xiong et al, Am J Obstet Gynecol 2000;183:148-55)
Preeclamptic group
LGA 10% SGA 10%
Normotensive group
LGA 5% SGA 5%
AGA 80%
AGA 90%
IMPACT OF PREECLAMPSIA ON BIRTH OUTCOMES
• Preeclampsia is associated with an increased risk of poor fetal growth (SGA, LBW) • Preeclampsia is associated with an excessive fetal growth (LGA, HBW) • Effect of preeclampsia on birth weight is a function of gestational age:
Fig. 7 Effect of PIH on birth weight by gestational age
(Xiong et al, American Journal of Epidemiology, 2002;155:203-9)
6000
Birth weight (grams)
Normotensive status
Gestational hypertension
Preeclampsia
5000 4000 3000 2000 1000 0
=<32 33
34
35
36
37
38
39
40
41 =>42
Gestational weeks
IMPACT OF PREECLAMPSIA ON BIRTH OUTCOMES • Preeclampsia is associated with an increased risk of poor fetal growth (SGA, LBW) • Preeclampsia is associated with an excessive fetal growth (LGA, HBW) • Effect of preeclampsia and gestational hypertension on birth weight is a function of gestational age: – Effect of decreased birth weight is found mostly among preterm births. (38.8% preeclamptic women) – Most babies born to mothers with preeclampsia at term actually have normal birth weight for expected gestational age . (61.2% preeclamptic women)
Implications to pathophysiology of preeclampsia?
Most babies born to mothers with preeclampsia, especially born at term, have normal fetal growth. These findings do not endorse the currently held theory that reduced uteroplacental perfusion is the unique pathophysiologic process in preeclampsia.