Introduction

Pediatrician Dr. Paul Smolen here. Parents are often bewildered by some of the bizarre physical symptoms their babies develop soon after birth. Stay tuned and I will break down some of these unexpected baby bodily changes in today's installment of Portable Practical Pediatrics.

Musical Intro

Science Drive of Pregnancy

Pregnancy and the first few months of life for a baby are a time of radical change with respect to their hormone balance as well as the germs that live on their skin. These changes cause some unexpected physical symptoms in many babies, possibly some that you have or are going to see in your children. Understanding the biology of what's going on with your baby is essential to having insight into your baby's changing physiology so let's take a quick tour down Science Drive to better understand these changes, shall we?

--Radical Change Number One-Hormones Come and Go

First, let's consider the changes that babies experience with regards to hormones. You remember learning about hormones in biology class- those circulating chemicals that turn on or off various tissue functions in your baby's body. Think about a baby being exposed to the large amount of estrogen that is required to keep a pregnancy going all the way to term. This has a tremendous effect on a wide variety of an infant's bodily systems. Think about it, as far as hormones, your baby has been pregnant along with their mothers. I know what you are thinking,  "If I have a boy, estrogen doesn't effect boys right?" Yes it does as I am about to describe to you in a minute!  Just because your baby is a boy doesn't mean that their cells don't know what estrogen is and what to do when it is around as you about to see.

Shifting gears, now imagine the effects on your baby when suddenly all that estrogen disappears- at delivery.  Suddenly, your infant is no longer pregnant hormonally and you can begin to see the effects of the male hormone that babies have small amounts of- testosterone. And for those of you with daughter babies, yes, girls make a small amount of testosterone and it has effects on them as well. Their cells know what to do when turned on by testosterone just like the boys and estrogen. Shortly after birth, your baby's little endocrine system is getting whiplash now with all this hormonal flux isn't it!

Now let's make the leap between hormone levels and what these hormones do an to an infant's body. Here is a short summary of the effects of estrogen and testosterone on your baby's body:

First let's start with the effects of estrogen and other female hormones on your baby

Estrogen promotes breast growth- Pregnancy is the ultimate high estrogen state and just ask any pregnant mom about what happened to her breasts during her pregnancy!
Estrogen stimulates the lining of the uterus to grow thicker and become more vascular.
Estrogen stimulates vaginal cells to produce mucous, a thick mucous in response to estrogen stimulation.
And on the flip side, a sudden decrease in estrogen stimulates uterine bleeding- shedding of the uterine lining- a period
And a sudden fall in estrogen also allows other hormones that moms produce (namely prolactin) to stimulate milk production.

Ok, that's the effects of estrogen or a sudden change in estrogen. How about the effects of testosterone

Remember, when mom's estrogen levels precipitously fall, the effects of testosterone start to become more pronounced in your baby, temporarily in the few months after birth.

Testosterone promotes oil production in your baby's skin in areas where they have a lot of oil glands- their face and scalp. Under certain conditions, this can even lead to acne, just like teenagers get, especially with all the new microbes that are living o...