You may have gone into first-time parenthood armed with knowledge from books, the internet, and experiences and advice shared by those who had already "been there, done that" — but I think we can all agree that nothing quite prepares you for actually having a baby.
Before you became a mother, you may have known — as research confirms — that many new moms experience "feelings of surprise and confusion" alongside feelings of excitement and love . You'll certainly have been aware that most mothers report being "physically exhausted" in the first postpartum months, that many experience physical pain from pregnancy, birth, and breastfeeding, and that sleep is hard to come by with a newborn . On the more positive side, you'll have read about the overwhelming love you'd feel toward your baby in many books while you were pregnant, and have heard about it from many already experienced parents.
Now armed with first-hand experience, will you have an easier time adjusting to life with a second baby — or will the transition to parenting two be so great that it will actually be harder? These questions will certainly be on the minds of mothers expecting another baby, but they don't need to cause you too much worry.
Neither Easier Nor Harder, But Just Different?
First-time mothers go from childless to being parents, a process that leads to a significant shift in their sense of identity. Research shows, for instance, that the transition to motherhood often involves a shift from being oriented outward, to the rest of the world including the workplace, to being oriented inward, to a much smaller group of friends and relatives.  (I have to admit that sounded ridiculous to me — an independent, modern woman — upon reading it, but then I remembered the times I decided to stay in with my baby rather than go out to leave her with a babysitter.)
Another study points to this process as well, by indicating that this "role differentiation" hits some first-time mothers hard. Going from shaping your workplace and the world to being at home, changing diapers, and missing sane adult conversation (even temporarily) isn't easy by any stretch of the imagination. Not only do you grow into your new life (and whatever it's like, it'll be different to what it was before you became a mother) over time, you'll also make new connections, both with adults and with your child, in which your motherhood is central.
By the time you have a second baby, you'll already have a pretty good idea of what role you have in your own unique family, as well as having had time to work out exactly how you want to balance motherhood with the rest of your life. The study shows, however, that first- and second-time mothers experienced about the same levels of stress — although the sources of stress may be quite different. Interestingly, second-time mothers did find a greater source of comfort in their marriages when it came to combating that stress. This makes sense, as fathers, too, become more confident in that role gradually.
How Does The Birth Of A Second Baby Impact Your Relationship With Your First Child?
When you think about it, the birth of a second baby really has the potential cause major change in two areas — the way you handle the "workload" of having two kids, and the relationship with your firstborn.
Research is pretty clear about the fact that the transition to siblinghood can temporarily be disruptive for a firstborn. Feelings of loss, jealousy, and anger can crop up.  If this happens, it will present a unique challenge you've never dealt with before. These feelings are hardly universal, however, and a very interesting study  found four possible scenarios:
- The birth of a second baby doesn't cause any changes, or only very minor ones, in your relationship with your firstborn — 46.8 percent of participants found this to be the case.
- Your first child does have negative reactions to the birth of a sibling, which 21.3 percent of parents reported.
- You're the one who causes negative vibes, by becoming more scolding and punitive toward your firstborn. Interesting, with this happening in 25.5 percent of the cases the researchers observed, this wasn't all that uncommon.
- Lastly, 6.4 percent of families had a situation in which the mother's relationship with her first child was impacted positively by the arrival of a second baby. Listen up here — this was more frequently the case in families where fathers took on much more of an active role in relation to the first child after the second was born! Fathers are part of the picture that isn't discussed often enough, but they are important.
As you're helping your older child adjust to a new baby sibling, you're aiming, I'd say, for either the first or the last possibility — but even if you do encounter some, ehm, challenges in the early stages, remember that they don't have to last forever. During any difficult moments, remind yourself that sibling relationships are among the most important bonds out there, and that brothers and sisters are likely to be an enormous source of comfort and joy throughout life. 
You've got this. It might not be easy at all times, but you've got this. Keep in mind that over 80 percent of people have at least one sibling in the US , and that all those parents once went through the process you're about to embark on. Once the sleepless fog of caring for a newborn lifts, a whole new life as a mom of two is waiting for you. As well as this being tough on occasion, it's also an awful lot of fun.