NF1 and preeclampsia: A population-based study covering over 19 million pregnancies between 1988 and 2009 identified 1553 NF1-associated cases (prevalence: 0.008%), with significantly increased risks of gestational hypertension (adjusted odds ratio [AOR] 1.6; 95% CI: 1.2–2.0), preeclampsia (AOR 2.8; 95% CI: 2.3–3.4), intrauterine growth restriction (AOR 4.6; 95% CI: 3.7–5.6), preterm labor (AOR 1.6; 95% CI: 1.4–1.9), and cesarean delivery (AOR 2.0; 95% CI: 1.8–2.3).