Lower systolic blood pressure levels in early pregnancy are associated with a decreased risk of early-onset superimposed preeclampsia in women with chronic hypertension: a multicenter retrospective study

Akihiko Ueda, Masaaki Hasegawa, Noriomi Matsumura, Hiroshi Satō, Kenzo Kosaka, Kaoru Abiko, Shinya Yoshioka, Takaaki Yoshida, Keiji Tatsumi, Toshihiro Higuchi, Kohei Fujita, Shoko Sasaki, Masaki Goto, Hiroshi Takai, Yoshitsugu Chigusa, Haruta Mogami, Norimasa Sagawa, Masaki Mandai, Eiji Kondoh, on behalf of the KAMOGAWA study group