( However ( , ( ( ( ( ( ( carrying and ) giving ) birth ) ( to ( a ( large fetus ) ) ) ) ( is ( risky ( for ( the mother ) ) ) ) ) . ) ) )
(ROOT (S (ADVP (RB However)) (, ,) (VP (VBG carrying) (CC and) (VBG giving) (NP (NN birth)) (PP (TO to) (NP (DT a) (JJ large) (NN fetus)))) (VP (VBZ is) (ADJP (JJ risky) (PP (IN for) (NP (DT the) (NN mother))))) (. .)))
However, carrying and giving birth to a large  fetus is risky for the mother.
(ROOT (S (NP (JJ Placental) (NNS mammals)) (VP (VBP give) (NP (NN birth)) (PP (TO to) (NP (ADJP (RB relatively) (JJ large)) (NNS fetuses)))) (. .)))