By six months old a baby’s muscles should have strengthened, and they should have mastered the ability to roll over, even several times at once.

Babies are born with soft heads, allowing them room for their brains to grow. If a baby lays or sleeps in one position too often, that portion of his or her head may become flat, called “flat head syndrome”. If babies are laying down most of the day, this syndrome is more likely. To avoid flat head syndrome, hold your baby for periods of time during the day, either in your arms or in a baby carrier, change their sleeping position regularly, and practice appropriate amounts of “tummy time”.

Folic acid helps prevent neural tube defects (NTDs)—serious birth defects of the spinal cord (such as spina bifida) and the brain (such as anencephaly).

Sometimes, female infertility is related to a hormone problem. In this case, symptoms can also include: skin changes, including more acne, changes in sex drive and desire, dark hair growth on the lips, chest, and chin, loss of hair or thinning hair, weight gain.

Some of the most common side effects of pills are bleeding between periods (most often with progestin-only pills), breast tenderness nausea and vomiting. They usually clear up after two or three months.

You should swallow the pill at the same time every day, whether or not you have sex. If you miss one or more pills, or start a pill pack too late, you may need to use another method of birth control, like a condom.