Preeclampsia, gestational hypertension and intrauterine growth restriction, related or independent conditions?
OBJECTIVE
Preeclampsia, gestational hypertension, and unexplained intrauterine growth restriction may have similar determinants and consequences. In this study, we compared determinants and perinatal outcomes associated with these obstetric conditions.


METHODS
We analyzed 39,615 pregnancies (data from the WHO Antenatal Care Trial), of which 2.2% were complicated by preeclampsia, 7.0% by gestational hypertension, and 8.1% by unexplained intrauterine growth restriction (ie, not associated with maternal smoking, maternal undernutrition, preeclampsia, gestational hypertension, or congenital malformations). We compared the risk factors associated with these groups. Fetal death, preterm delivery, and severe neonatal morbidity and mortality were the primary outcomes. Logistic regression analyses were adjusted for study site, socioeconomic status, and (if appropriate) birth weight and gestational age.


RESULTS
Diabetes, renal or cardiac disease, previous preeclampsia, urinary tract infection, high maternal age, twin pregnancy, and obesity increased the risk of both hypertensive conditions. Previous large-for-age birth, reproductive tract surgery, antepartum hemorrhage and reproductive tract infection increased the risk for gestational hypertension only. Independent of maternal age, primiparity was a risk factor only for preeclampsia. Both preeclampsia and gestational hypertension were associated with increased risk for fetal death and severe neonatal morbidity and mortality. Mothers with preeclampsia compared with those with unexplained intrauterine growth restriction were more likely to have a history of diabetes, renal or cardiac disease, chronic hypertension, previous preeclampsia, body mass index more than 30 kg/cm2, urinary tract infection and extremes of maternal age. Conversely, unexplained intrauterine growth restriction was associated with higher risk of low birth weight in previous pregnancies, but not with previous preeclampsia. Both conditions increased the risk for perinatal outcomes independently but preeclampsia was associated with considerable higher risk.


CONCLUSIONS
Preeclampsia and gestational hypertension shared many risk factors, although there are differences that need further evaluation. Both conditions significantly increased morbidity and mortality. Conversely, preeclampsia and unexplained intrauterine growth restriction, often assumed to be related to placental insufficiency, seem to be independent biologic entities.
United Nations Development Programme/United Nations Population Fund/World Health Organization/World Bank Special Program of Research, Department of Reproductive Health and Research, World Health Organization, Geneva, Switzerland. villarj@who.int
José
J
Villar
Guillermo
G
Carroli
Daniel
D
Wojdyla
Edgardo
E
Abalos
Daniel
D
Giordano
Hassan
H
Ba'aqeel
Ubaldo
U
Farnot
Per
P
Bergsjø
Leiv
L
Bakketeig
Pisake
P
Lumbiganon
Liana
L
Campodónico
Yagob
Y
Al-Mazrou
Marshall
M
Lindheimer
Michael
M
Kramer
D005260:Female; D005317:Fetal Growth Retardation / Q000453:epidemiology / Q000209:etiology; D006801:Humans; D046110:Hypertension, Pregnancy-Induced / Q000453:epidemiology / Q000209:etiology; D007231:Infant, Newborn; D011225:Pre-Eclampsia / Q000453:epidemiology / Q000209:etiology; D011247:Pregnancy; D011256:Pregnancy Outcome; D012307:Risk Factors