- Your pregnancy: The third trimester
- When does the third trimester start? When does it end?
- What are some of the pregnancy symptoms in the third trimester?
- What kinds of medical tests and screenings take place in the third trimester?
- What’s happening with baby in the third trimester?
Your pregnancy: The third trimester
All of your questions about the long awaited third trimester—and those never-ending pregnancy symptoms—answered.
By Today’s Parent August 12, 2019
Here you are: the home stretch! In some ways it probably feels like your pregnancy is passing at warp speed; in other ways, it seems like it’s never-ending. Your body and your baby continue to grow and change in important and amazing ways throughout your third trimester. Here’s a closer look at what might be in store for you in your final months of pregnancy.
When does the third trimester start? When does it end?
Your third trimester begins at week 28 and lasts, well, until you deliver your baby. An average pregnancy lasts about 40 weeks—if you deliver before 37 weeks, it’s considered preterm, and 39 or 40 weeks is full-term. Some pregnancies go into 41 or even 42 weeks, and at that point your healthcare provider will talk about options for inducing labour.
What are some of the pregnancy symptoms in the third trimester?
Prolactin, the hormone that stimulates your breasts to get ready for milk production, increases steadily in your third trimester—it’s 10 times higher at the end of your pregnancy than it was at the beginning. At 32 weeks and beyond, you may leak a bit of colostrum, which is the “liquid gold” nutrient-rich fluid that your body makes before your breastmilk fully comes in. If you’re breastfeeding, this will be your baby’s first food, and this is just practice for the big event. You may notice stretch marks or broken capillaries on your breasts because they’ve grown so much fuller during your pregnancy (these may fade in time, but they’ll probably be your mama badges of honour now).
Heartburn and acid reflux
You may find yourself dealing with heartburn in your third trimester—your expanding bump puts pressure on your digestive system, and higher progesterone levels may relax the sphincter at the bottom of your esophagus and cause stomach acid to travel upward. Constipation (sometimes accompanied by hemorrhoids) and diarrhea can be not-so-fun issues in late pregnancy, due to hormones, prenatal vitamins and pressure from your growing belly. Talk to your healthcare provider about the kinds of over-the-counter meds and food choices that will help you feel better.
Pregnancy cramps and contractions
Cramps during pregnancy can also be worrisome, but the good news is that they’re fairly common and usually no cause for concern. A warm shower may relieve pain from cramping, and a maternity support belt in the third trimester can help ease cramping and back pain. The important thing is to figure out why they happen (such as ligament pain or sex) and learn when to seek help for them.
88 things nobody tells you about being pregnant You may also feel irregular Braxton Hicks contractions, where the uterus muscles tighten and contract for up to a minute. They are nothing to worry about—just your body gradually getting ready for go-time. Often, pre-labour contractions will disappear if you take a warm bath or apply a hot water bottle wrapped in a towel to the affected area.
Aches and pains
The third trimester can be uncomfortable for a lot of women, with a variety of aches and pains, including backache, rib or hip pain, leg cramps and carpal tunnel syndrome. There’s also “lightning crotch,” the non-medical but very accurate description of a shooting electric pain in the pelvic area caused by the pressure of your growing baby on your nerves. There’s no magic cure, but you don’t just have to grit your teeth for weeks on end; depending on the issue, foam rollers, certain exercises and positions, supplements and increased water can provide some relief.
Early signs of labour
If those Braxton Hicks contractions start to ramp up in frequency, they could be more than “practice contractions” and be a sign of early labour. Not sure what real contractions feel like? The difference is that they are exceptionally strong and painful and won’t let up until the baby is born. Many women describe contractions as achy, period-like cramps, while others feel them mostly in their backs. Contractions can be quite varied—take a look.
The feeling that your baby has “dropped” into your pelvis, along with nausea and loose stools, could be a sign that your baby will arrive sooner rather than later. Read on for more signs of early labour and when to head to the hospital.
During the second half of pregnancy, bleeding can be caused by a placental abruption (where the placenta partially detaches from the uterine wall), but in most cases, it doesn’t pose a danger to the mother or baby. Bleeding may also be caused by placenta previa (where the placenta partly or completely covers the cervix), which can be risky if it continues into the third trimester. You should report any vaginal bleeding during pregnancy to your healthcare provider and be prepared to describe how much blood you’ve passed and what it looks like.
Restless leg syndrome
Restless leg syndrome, which may feel like cramps, twitches or a need to move your legs when you’re lying down at night, arises in about 30 percent of pregnancies. It’s one of those harmless yet annoying issues, so talk to your healthcare provider about potential remedies, including magnesium, exercise, massage and Epsom salt soaks. Speaking of legs, you may notice varicose veins (swollen veins near the surface of the skin). They are often found on your calves, but they may appear higher on your legs and in the vulvovaginal area. Progesterone causes blood to pool in these veins, and your growing uterus also compresses some of the blood flow returning to the heart. Check with your healthcare provider, who may recommend staying off your feet, exercising to improve blood flow and wearing compression socks or shorts.
Heart fluttering (a feeling like your heart is racing or skipping a beat) is somewhat common in late pregnancy. This may be how your body adjusts to changes in circulation or your growing belly, but it’s worth talking about with your healthcare provider.
Pregnancy hormones and discharge
Estrogen and progesterone peak at about 32 weeks. The extra estrogen may be linked to your swollen ankles because it indirectly affects how your body retains fluids. But if you notice a lot of puffiness, combined with headaches and vision changes, get to the hospital ASAP to be evaluated for pre-eclampsia, a serious condition that can affect both you and your baby. Noticing more vaginal discharge (thin, milky-white and odourless or near-odourless) than usual? It’s called leukorrhea and totally normal, due to extra estrogen, as well as more blood flow to your pelvis. You also have a mucus plug, which blocks the cervix to keep bacteria from entering the uterus. Toward the end of your pregnancy, as your cervix ripens and changes, this plug may move down into your vagina and show up as pink or red-tinged mucus (also known as a “bloody show”). It doesn’t mean that labour is on its way, though, and some women don’t notice it at all. Dizziness, fatigue and frequent urination may have followed you from your first and second trimesters, too.
What kinds of medical tests and screenings take place in the third trimester?
You may have one or more ultrasounds in your third trimester if your healthcare provider wants to check on your baby’s growth or position, amniotic fluid levels or your placenta. Alternatively, you may not have any ultrasounds at this point—it just depends on how you and the baby are doing. Your urine and blood pressure will be checked at every appointment, just like earlier in your pregnancy (this is a way of detecting pre-eclampsia). Between weeks 35 and 37, your healthcare provider will take a swab of your vagina and rectum (or you may be able to do this yourself at your appointment) to check for group B streptococcus (GBS) bacteria, which is harmless to you but may be dangerous to your baby during delivery. If you test positive, you may receive antibiotics during labour.
Around 28 weeks, your healthcare provider will probably talk to you about doing “kick counts” (the number of kicks or movements in a set time period). This is a way to keep an eye on your baby’s movements.
You can safely get a flu vaccine at any point during your pregnancy—and, in fact, it’s recommended. One new recommendation is to get the TDAP (tetanus, diphtheria and pertussis) vaccine, between 27 and 32 weeks, so that you can pass on potentially lifesaving antibodies to your baby before they’re born.
Stretch and sweep
Around 38 weeks, your healthcare provider may offer a “stretch and sweep” or “membrane stripping,” where a gloved finger is inserted into the cervix to help separate the membranes that connect the amniotic sac to the wall of the uterus. This releases prostaglandins to help prepare the cervix for labour (this is totally your call, though).
What’s happening with baby in the third trimester?
Your baby will start to gain weight more rapidly in the third trimester—about a pound every two weeks—though that growth will slow down toward the end (fortunately). They will start out about the size of a head of broccoli and typically end up the size of a seven-pound bag of flour or an eight-pound pumpkin—though, of course, birthweight varies quite a bit. Brain development is a big deal during the third trimester, as nerve cells separate into five different parts of the brain. Your baby might get the hiccups and, yep, you can feel them, too! Around 32 weeks, many babies move into the head-down position, which may change the shape of your bump. Toward the end of your pregnancy, your baby will shed the lanugo (fine, downy hair all over the body) and vernix (the white coating on the skin) into the amniotic fluid. Some of that amniotic fluid will get swallowed to become your baby’s first poop (a thick, dark goop called meconium). Research suggests that babies send out particular proteins or hormones that will start the chain reaction of labour in late pregnancy. Time to meet your little one at last—congrats!LESEN SIE MEHR: