Consider a series of studies that examined length of maternity leave in relation to employed mothers' psychological well-being and parenting behaviors.
( ( Consider ( ( a series ) ( of ( studies ( that ( ( ( examined ( length ( of ( maternity leave ) ) ) ) ( in relation ) ) ( to ( ( employed ( mothers ' ) ) ( psychological ( well-being ( and ( parenting behaviors ) ) ) ) ) ) ) ) ) ) ) ) . )
(ROOT (S (VP (VB Consider) (NP (NP (DT a) (NN series)) (PP (IN of) (NP (NP (NNS studies)) (SBAR (WHNP (WDT that)) (S (VP (VBD examined) (NP (NP (NN length)) (PP (IN of) (NP (JJ maternity) (NN leave)))) (PP (IN in) (NP (NN relation))) (PP (TO to) (NP (NP (JJ employed) (NNS mothers) (POS ')) (JJ psychological) (NN well-being) (CC and) (NN parenting) (NNS behaviors)))))))))) (. .)))
The study revealed that  the shorter the maternity leave, the worse the mental health.
( ( The study ) ( ( revealed ( that ( ( ( the shorter ) ( ( the maternity ) leave ) ) ( , ( ( the worse ) ( the ( mental health ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NN study)) (VP (VBD revealed) (SBAR (IN that) (X (SBAR (X (DT the) (ADJP (JJR shorter))) (S (NP (DT the) (NN maternity)) (VP (VBP leave)))) (, ,) (X (DT the) (ADJP (JJR worse))) (NP (DT the) (JJ mental) (NN health))))) (. .)))