The second bit - δεινόν τὸ τίκτειν ἐστίν - is also from Sophocles, Electra l. 770. Loeb doesn't give me access anymore (it seems you can only view two or three pages there for free).
Wikisource has a translation from 1878 by a guy called Plumptre. The line that starts with your phrase and the next one read like this there:
Wondrous and strange the force of motherhood!
Though wronged, a mother cannot hate her children.
https://en.wikisource.org/wiki/Trage..._1878)/Electra
The full two lines in Greek go like this:
δεινὸν τὸ τίκτειν ἐστίν· οὐδὲ γὰρ κακῶς
πάσχοντι μῖσος ὧν τέκῃ προσγίγνεται.
https://el.wikisource.org/wiki/%CE%9...BA%CE%BB%CE%AE)
What I can't help you with is which bit in English translates the first four words of the Greek...