A complicated question. I have done two studies on that with very small samples, so it is hard to generalise from it. When you say across cultures, you mean what would be universal for all. Both my research projects on it involved those who experienced war. I did have a student who wrote her masters research paper on pregnant teens, and social support which won an award. I would have to look for it. I do remember that one of her main findings for teenage girls and where they got the majority and best of their social support was from older sisters.
Personally - in eastern culture, family is regarded as the spine to a body. Being entrusted with children be them a given or unexpected do not diminish the "spine" itself. In fact, it is the love and trust that keep the young adults bounce back. This is especially true for those living a clanship life especially in remote Indonesia where money cannot buy everything especially love and trust of their elders. This is also known as the psychosocial effect amidst the social identity already created thousands of years ago.
In modern eastern country like Singapore, what bounces the young adults are the resilience in the form of monetary cringe alias economic essence. Without money, the choice left is only to abort or adhere to the societal norm by working hard, support the family, care for the unexpected and move on with life - with part-time tertiary education like in SIM University - because a degree is worth sacrificing for the little one and an assurance to life's little luxuries.
I have seen the western culture in raising children, wanted or brought upon unexpectedly. I may be wrong - but most of them have this individualism syndrome that diminish the family structure somewhat.
Then again, things have change. I have also seen the cross culture of the west marrying the east bouncing up trying to gain an identity in the universal world. It is not a matter of resilience in the sense of a brought upon parents but the onus of being strong in the midst of the cultural diversity.