( Pregnancy ( ( causes ( ( other changes ) ( in ( estrogen levels ) ) ) ) . ) )
(ROOT (S (NP (NNP Pregnancy)) (VP (VBZ causes) (NP (NP (JJ other) (NNS changes)) (PP (IN in) (NP (NN estrogen) (NNS levels))))) (. .)))
Pregnancy causes other changes in estrogen levels.
(ROOT (S (NP (NNP Estrogen)) (VP (VBZ causes) (NP (NP (DT the) (NNS changes)) (PP (IN of) (NP (NN puberty))))) (. .)))