When I hear that a friend or family member are in labor, I almost always light a candle for them. Often times, depending on gestation time, history, and length of labor, I also add in some protective, healing energies.
Do I ask for permission before hand? No, I don't. Why? Why go against what many Witches consider to be a major rule? Well, for one, it's not one of my rules. I believe that if someone can pray without my consent, then I can work magik for them. Am I conspiring against them or performing a Love Curse? No, it's just a simple spell to ensure that they have a safe delivery and they and their child(ren) are healthy. There's nothing bad about that. No malice.
Some pray, I cast. No difference.
And I will say this, when my son was in the hospital, some people asked me if they would pray or have a priest perform a blessing. I don't care. You don't need to ask permission. I know it's coming from a good, untainted place. A place of love and compassion, why would I say no? Because you're of a different faith? Either way, consent or not, many people are going to pray regardless. They're going to ask their church for blessings over my son, no amount of consent is going to stop that.
No consent is needed when it comes from a place of love and compassion. Don't like my stance. Not sorry.