When Does the Third Trimester Start?

The End Is Near: The Last Stage of Pregnancy

In some ways, reaching the third trimester feels like a relief. Your baby has developed enough at this point that she could survive if you go into labor early, and at least two-thirds of the pregnancy is behind you. So while you might be delighted to enter the home stretch, there's no denying that the third trimester has its own surprises and challenges in store. Above all, the beginning of the third trimester is an exciting marker that means you're going to meet your baby soon.

The Third Trimester

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What Is a Trimester?

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There's some disagreement about when exactly the third trimester begins. Some people swear it starts at the beginning of the 26th or 27th week. Still others say it starts with week 29, but most experts say week 28 is the tipping point. At that point, you theoretically have exactly 12 weeks, or three months, left in a 40-week pregnancy. So it's safe to say you're in your third trimester once you hit the seven-month mark.

Body and Baby Changes

Although your body might already feel like it's changed completely, the third trimester brings even more new sensations. You should continue to gain about a pound per week. As the baby grows and space gets tighter, the pressure on your back and bladder can increase, and you might experience some shortness of breath.

The third trimester tends to be even more tiring than the second trimester, and the fact that you'll probably have to get up to pee several times each night contributes to fatigue. Heartburn and swelling of the face, feet and ankles are common. Basically, it can be pretty hard to get comfortable during this period.

Meanwhile, your baby continues to grow and mature. His hair might be growing in, and his bones are hardening. He's gaining weight, his skin is smoothing out, and his fingernails and toenails are growing in. Around the middle of the third trimester, he should start preparing for birth by moving into a head-down position. Some babies don't make this move. Your doctor will check your baby's position and talk to you about options during your appointments in the final weeks of pregnancy.

More Frequent Doctor Visits

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Women who are having typical pregnancies will probably need to see their doctors every two weeks during the beginning of the third trimester. Your doctor will probably want to see you once a week once you enter your 35th or 36th week and get close to delivery. Don't hesitate to call your doctor with any concerns or new symptoms during the third trimester. This period is especially nerve-wracking for first-time moms.

If your pregnancy is high risk or you're having multiples, you'll probably need more frequent appointments during this period. Bed rest is sometimes prescribed during the third trimester for high-risk pregnancies.

Preparing for Birth

In addition to getting lots of rest and seeing your doctor often, you can take care of yourself during the third trimester by preparing for life with a newborn. Spend extra one-on-one time with older kids now, stock your freezer with healthy meals and arrange child or pet care for when you go into labor.

If you haven't done so yet, now's the time to create your birth plan and pack your hospital bag. Buy and install a car seat, set up the crib and organize all those tiny socks and stacks of diapers. Nesting is a natural impulse during the third trimester, so feel no guilt if you're spending time organizing picture frames and surfing Pinterest while your spouse does the cleaning. Hey, it's what the baby wants!

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