Your pregnancy: 40 weeks

See the big picture

How your baby's growing:

It's hard to say for sure how big your baby will be, but the average newborn weighs about 7 1/2 pounds (a small pumpkin) and is about 20 inches long. His skull bones are not yet fused, which allows them to overlap a bit if it's a snug fit through the birth canal during labor. This so-called "molding" is the reason your baby's noggin may look a little conehead-ish after birth. Rest assured — it's normal and temporary.

See what your baby looks like this week.

Note: Every baby develops a little differently — even in the womb. Our information is designed to give you a general idea of your baby's development.

How your life's changing:

After months of anticipation, your due date rolls around, and... you're still pregnant. It's a frustrating, but common, situation in which to find yourself. You may not be as late as you think, especially if you're relying solely on a due date calculated from the day of your last period because sometimes women ovulate later than expected. Even with reliable dating, some women have prolonged pregnancies for no apparent reason.

You still have a couple of weeks before you'll be considered "post-term." But to be sure your baby is still thriving, your practitioner will schedule you for testing to keep an eye on her if your pregnancy continues.

You may have a biophysical profile (BPP), which consists of an ultrasound to look at your baby's overall movements, breathing movements (movement of her chest muscles and diaphragm), and muscle tone (whether she opens and closes her hand or extends and then flexes her limbs), as well as the amount of amniotic fluid that surrounds her (important because it's a reflection of how well the placenta is supporting your baby).

Fetal heart rate monitoring (called a nonstress test or NST) will generally be done as well — by itself or as part of the BPP. Or, you may have what's known as a modified BPP, which consists of an NST and an ultrasound to assess the amount of amniotic fluid.

If the fetal testing isn't reassuring — the amniotic fluid level is too low, for example — you'll be induced. If there's a serious, urgent problem, you may have an immediate c-section.

Your practitioner will also check your cervix to see if it's "ripening." Its position, how soft it is, how effaced (thinned out) it is, and how dilated (open) it is can all affect when and how your labor is induced. If you don't go into labor on your own, you'll be induced, usually sometime between 41 and 42 weeks.

3 Questions About...Inducing labor

Q1.

What does it mean to induce labor?

If your labor doesn't start on its own, your practitioner can use certain medications and techniques to help bring on or "induce" contractions. She'll do this when the risks of prolonging your pregnancy are higher than the risks of induction. Most practitioners will induce labor if you're still pregnant between one and two weeks after your due date. This is because the placenta may become less effective at delivering nutrients at around 42 weeks, and other serious complications become more likely as you pass your due date.

Q2.

How is labor induced?

There are a variety of methods, and the one your practitioner uses will depend on your individual situation — in part, on the condition of your cervix (whether it's ripe or not) and the urgency of the induction.

Typically, if you need to be induced but your cervix is not yet dilated or thinned out, you'll be admitted to the hospital and your caregiver will likely start off the induction by inserting medication that contains prostaglandins into your vagina. This medication helps to ripen the cervix and may also stimulate enough contractions to start your labor.

If the prostaglandins don't put you into labor, your caregiver will then administer a drug called Pitocin (also known as oxytocin). It's given through an IV and used to start labor or augment contractions you've been having on your own. (If your cervix is ripe to begin with, she'll start with the Pitocin straightaway.)

Q3.

Are there any techniques for kickstarting labor that I can try myself?

There are no do-it-yourself techniques consistently proven to be both safe and effective so don't try anything without guidance from your caregiver. Here's the scoop on some of the methods you may have heard about:

• Sexual intercourse: Semen contains prostaglandins and having an orgasm may stimulate some contractions. A few studies have shown that having sex at term may decrease the need for labor induction, but others have shown it has no effect on promoting labor.

• Nipple stimulation: Stimulating your nipples releases oxytocin, and it may help start labor, but more research is needed to determine the safety and effectiveness of this method. Because it may overstimulate your uterus, your contractions and your baby's response to them would need to be monitored so don't try this at home.

• Castor oil is a strong laxative, and stimulating your bowels may cause some contractions. There's no definitive proof that it helps induce labor though plenty of women can attest to its unpleasant effects!

• Herbal remedies: A variety of herbs are touted as useful for labor induction. Some are risky because they can cause contractions that are too long or too strong and may be unsafe for your baby for other reasons as well. For others, the safety and effectiveness remain unknown.

This Week's Activity:

Kick back and relax. Rent some movies, read a novel, curl up with a stack of magazines or a new CD, sleep in or grab catnaps when you can.You're in the final stretch and you deserve some downtime! If you're go-go-go right up until delivery you'll be depleted by the time your baby arrives, says clinical psychologist Diane Sanford.