Armstrong et al have asserted that pregnancies associated with placental insufficiency exhibit lower maternal plasma KISS1 levels in the 2nd trimester.[21] In a study conducted by Smets et al, it was reported that low plasma KISS1 levels in the first trimester were associated with low birth weight.[22] Although the differences in KISS1 levels observed in these studies were moderate, the measurement of KISS1, while not serving as a standalone screening marker in preeclampsia and intrauterine growth restriction, was considered potentially useful when used in conjunction with other markers. The gene discussed is KISS1; the disease is placental insufficiency.