By four months, a baby should have developed the neck strength to hold his or her head unsupported, to stick his or her hands in the mouth, perhaps sucking on fingers, and to watch things move with his or her eyes.

The amount of blood in your body will rise dramatically during pregnancy. By the time you give birth, you'll have about 50 percent more blood circulating than usual.

You should gain weight gradually during your pregnancy, with most of the weight gained in the last trimester.

Being overweight or significantly underweight can affect hormone production and inhibit normal ovulation. Maintaining a healthy weight can increase the frequency of ovulation and likelihood of pregnancy.

IVF offers higher pregnancy and live birth rates than ovarian hyperstimulation. Like ovarian hyperstimulation, the chances of success diminish with age.

Ovulatory disorders are the most common cause of infertility in women. For you to successfully produce an egg each month requires a complex interaction between hormones produced by your brain and your ovaries.