New-onset hypertension in late pregnancy is associated with lower fetal and infant mortality in preterm twins.
OBJECTIVE
To assess the association between new-onset hypertension in late pregnancy (NOH) and fetal and infant mortality in early preterm, late preterm, and full-term twins.


METHODS
We conducted a retrospective cohort study in 275, 316 twins in 1995-1997 based on multiple birth registration dataset of USA. Generalized estimating equations (GEEs) was used to evaluate the odds ratios (OR) of fetal and infant death (at individual level) associated with NOH, with adjustment of potential confounders at both twin set level and individual level.


RESULTS
The risks for early neonatal death (OR = 0.52, 95% CI: 0.36, 0.76) and late neonatal death (OR = 0.57, 95% CI: 0.37, 0.87) were decreased in early preterm twins born to mothers with NOH compared with early preterm twins born to mothers with normal blood pressure. The decreased risks for fetal death (OR = 0.40, 95% CI: 0.30, 0.53; OR = 0.46, 95% CI: 0.53, 0.65) and infant death (OR = 0.35, 95% CI: 0.28, 0.44; OR = 0.68, 95% CI: 0.51, 0.91) were associated with NOH in both early and late preterm twins, whereas no association between NOH and fetal/infant mortality were observed in full-term twins.


CONCLUSIONS
NOH is associated with lower risk of fetal death and infant death in preterm twins.
Chen
Xi-Kuan
XK
OMNI Research Group, Department of Obstetrics & Gynecology, University of Ottawa, Ottawa, Ontario, Canada.
Wen
Shi Wu
SW
Smith
Graeme
G
Yang
Qiuying
Q
Walker
Mark
M
D000328:Adult; D005260:Female; D046689:Fetal Mortality; D006801:Humans; D046110:Hypertension, Pregnancy-Induced / Q000503:physiopathology*; D007226:Infant Mortality; D007231:Infant, Newborn; D011247:Pregnancy; D011262:Pregnancy Trimester, Second / Q000502:physiology; D011263:Pregnancy Trimester, Third / Q000502:physiology; D047928:Premature Birth / Q000401:mortality* / Q000503:physiopathology; D014427:Twins / Q000502:physiology*