The third trimester begins in week 28 and goes all the way to week 40, though some women can even get to 42 weeks without giving birth. If the baby has not yet arrived by week 42, a soon-to-be mom should go see her doctor so that they can induce the labor. By the third trimester, most of the baby's vital organs and systems are ready for the outside world, and the ones that are yet to mature do so early in this trimester.

In preparation for the outside world, babies during this trimester begin to shed their hair and become a tad heavier. Mom’s body, on the other hand, will continue to undergo significant changes, including a notable increase on the scales as well as an increase in the size of the bump. In addition, all the aches, pains, and discomforts at this time will sure try to put her down, but all these will be worth nothing once she meets her baby.

Since doctors never want to worry first-time moms in any way—especially during this last leg of their journey—most refrain from mentioning some of the changes moms will undergo during this period.

Below is a list of changes the doctor might not tell first-time moms about the third trimester that moms should be aware of.

20 Moms Will Make Frequent Trips To The Bathroom

Doctors sometimes do not tell first-time moms about the symptoms they may experience as their pregnancy progresses so as not to alarm them. One of the symptoms includes making trips that are more frequent to the bathroom compared to the other two trimesters.

According to BabyCenter, the need to urinate during the third-trimester increases because the growing baby exerts more pressure on the mother’s bladder. To manage this, moms need to always empty their bladder completely and avoid drinking carbonated drinks as they increase urine production. As a precaution, moms should avoid holding in the urine as this weakens their pelvic floor muscles.

19 Get Ready To Waddle

In the final trimester, women develop a different walking style similar to a waddle. Doctors may sometimes not tell their patients this. It is normal for pregnant women to feel like a penguin during that homestretch period. TheBump points out that as the pregnancy grows, it causes a shift in the center of gravity.

In the third trimester, the baby moves into the birth canal and when this happens, mom ends up shifting positions to offset the added pressure on the belly. In order for her to find a comfortable way to get around, she has to waddle. Many pregnant women hardly notice a change in their walking style, but what really matters is their ability to move around.

18 There Will Be Major Hair Growth

Doctors may not mention some pregnancy symptoms to avoid scaring the mom-to-be. Pregnancy hormones can make the hair on the head thicker and fuller and do the same for body hair. Some women find that they grow hair in unwanted places like on their faces and bellies.

The androgen hormone produced during pregnancy includes the male hormone, testosterone. This hormone is responsible for all the hair growth on the body and can sometimes cause hair to grow in unexpected places where it has never grown before as stated by Mother and Baby. Not to worry, though, most of the additional hair will fall off soon after the baby is born.

17 Mom Can Get Severe Heartburn

During the last trimester, the growing bump usually pushes the stomach and its contents upwards causing a persistent burn known as heartburn. Heartburns normally occur when the valve between the stomach and the esophagus is not able to prevent food from passing back to the esophagus.

The extra production of progesterone relaxes the muscles in the esophagus that normally keep food and acids down the stomach as stated by What to Expect and because space is limited, any pressure exerted on the stomach will push food up. In order to manage heartburns, moms are encouraged to eat smaller frequent meals, avoid spicy, acidic foods, and wait an hour or so before lying down.

16 They Will Have Backaches

Sometimes doctors don't tell first-time moms that their growing belly may cause backaches. The extra pounds they gain during the third trimester put additional pressure on the back making it feel achy and sore. Another reason is the shift of mom’s center of gravity, which causes a change of posture causing backaches.

Another cause of back pains is the separation of the rectal abdominal muscles as the stomach expands. WebMD points out that to ease back pains; moms should maintain good body posture, avoid heavy lifting, wear comfortable shoes with good arch support, and stick with non-strenuous activities in their daily routine.

15 Sleep Deprivation And Crazy Dreams Are A Reality

Sleep deprivation is a problem doctor don't tell first-time moms of during their third trimester. According to utswmed, sleep becomes elusive because it is difficult for mom and her growing belly to get comfortable. Moms should try to sleep on their side if possible and support their backs with pillows and wedging another one between their knees.

Sleep deprivation normally affects 10% of pregnant women. On top of that, as they get closer to their due date, the fluctuating hormones can cause their dreams to be more vivid than normal. Many expectant moms experience these crazy dreams and can almost swear that what they dreamt of happened in reality.

14 Stretch Marks And PUPPP Rashes Are Sometimes Inevitable

Sometimes doctors don't tell moms that even though they have gone through the first and second trimesters without stretch marks, chances of getting them during the last trimester are even higher according to MotherLove. During the third trimester, the skin around the belly can stretch to its limit and produce these marks but their appearance depends on the woman’s genes.

These stretch marks are normally dark and visible and as if that is not enough, the woman can develop bumpy rashes known as polymorphic eruption of pregnancy, PUPPP rashes. The rash occurs on the stretched areas and normally clears after birth. To manage the stretch marks and rashes, moms should frequently moisturize their skin.

13 Shortness Of Breath Can Occur

As stated earlier, a baby grows bigger and heavier during the last trimester than in the other two. This also causes the uterus to expand and rise up to the diaphragm. According to Healthline, when the diaphragm moves approximately four centimeters from its normal position it somehow compresses the lungs.

What doctors don't tell first-time moms is that this can cause shortness of breath because mom is not able to breathe in as much air. Once the brain gets wind of all these changes, it will communicate to the body to let the air inhaled stay in the lungs longer so that the body can get as much oxygen as it needs for mom and baby. To manage shortness of breath, moms should maintain a good posture, prop up while sleeping, exercise, and avoid straining their bodies.

12 Mom Will Probably Have Braxton Hicks Contractions

A lot of expectant mom’s experience Braxton Hicks contractions during their third trimester. These false labor pains can make a first-time mom head to the hospital, yet they are normal and are nothing to worry about. According to WebMD, these Braxton Hicks occur in order to prepare the woman for real labor contractions.

Unlike real contractions, Braxton Hicks are not painful they are just uncomfortable. Furthermore, Braxton Hicks do not occur at regular intervals nor do they last long. Mom can get rid of them by changing her body position. She can also take advantage of them and practice her breathing exercise.

11 Moms Can Get Hemorrhoids

Hemorrhoids occur when veins in the rectum swell and burst causing leakage. Unfortunately, they are quite common during pregnancy and sometimes doctors may not tell first-time moms about them to avoid frightening them, as they are usually very painful.

The extra pressure during pregnancy is responsible for causing these veins to expand in size. Pregnancy also exerts pressure on them causing them to swell. Straining during bowel movements and standing up for too long can finally cause them to leak. According to Everyday Health, moms can manage the pain by taking sitz baths and using stool softeners. Eating foods high in fiber also prevents hemorrhoids.

10 Moms Will Experience Pelvic Pain

Doctors sometimes do not tell first-time moms that they will experience pelvic pain because they do not want to alarm them. During the third trimester, some moms experience pelvic pain as it is the body’s way of preparing them for childbirth. The baby descending into the pelvis and pressing on to the hips and pelvic causes this pain.

According to What to Expect, even the increase in progesterone levels during pregnancy causing relaxation of the joints and muscles and this can cause pain. The relaxing helps the pelvis become sufficiently pliable to accommodate the baby’s head as it comes down during birth.

9 Prepare For Some Leakage

By the time a woman is getting to her third trimester, the girls are usually a couple of sizes bigger, fuller, and even more tender. What moms-to-be should do is make sure they wear a supportive bra to avoid backaches. However, what doctors sometimes forget to tell first-timers is that their breasts may start leaking. This is completely normal, however, the body is preparing for the arrival of the baby!

This leaking fluid is the colostrum, which is the first milk, produced to nourish the baby in the first days of life. It is usually thick and yellowish according to Net Doctor. When moms start leaking, they can put on breast pads to help absorb the leakage.

8 Mom May Have Swollen Legs

Doctors sometimes don't tell first-time moms that in addition to having a big belly, they may end up with swollen legs. During the third trimester, circulation normally increases for the sake of the growing baby.

On top of that, the growing baby will exert a lot of pressure on the legs. This pressure causes the varicose veins found on the legs to swell making them visible through the skin. There is no prevention for this but mom can avoid making it worse by sitting with her legs and feet propped up and staying active, as pointed out by WebMD. Moms may also experience mild swelling in their hands and face because of excess fluid retention.

7 A Pregnant Belly Is Not Always Round

Just like women come in all different shapes and sizes, so do baby bumps. Although as long as a baby is developing well there is no need for moms to be concerned about the shape of their growing belly. This is why doctors don't feel the need to tell first-time moms this.

Moms can have small, large, high, low, loose, or tight bumps depending on their fitness level and the number of babies they have had. It takes a little longer for a first-time mom’s uterus to move up and out of their pelvis while subsequent pregnancies show a lot sooner because the abdominal wall already has laxity according to health. The shapes might also differ depending on the position of the baby.

6 Lightheadedness And Dizziness Are Common In Pregnancy

Sometimes doctors forget to tell first-time moms that they may experience lightheadedness, dizziness or may even faint during their third trimester. This occurs due to the rising hormones that cause vessels to relax and widen. The process helps increase the flow to the baby but slows the return in the veins to the mother.

This results in mom having lower BP, which reduces the flow to the brain, temporarily causing lightheadedness or dizziness. Other things that can cause dizziness include not eating or drinking enough food and water, standing up for long durations, staying out in the sun for long, having anemia and/or exercising too much.

5 Mom Can Get Weird Cravings

Craving edible foods during pregnancy is normal. Doctors don't tell moms that in their final trimester they may start craving and eating non-food items like clay, chalk, soft stone, or sand because only a small number of women develop this. The non-food items usually have little to no nutritional value.

This condition is called PICA and the exact reason why some women develop it is unknown, but according to US pregnancy, there may be a connection to an iron deficiency or poor nutrition. Depending on what non-food item a mom ingests, she can get an infection, ingest harmful content, or begin constipating and therefore a mom must avoid such "delicacies."

4 Mom Can Get Joint Pains

Doctors hardly ever tell first-time moms that during pregnancy, women can experience increased joint and muscle pain due to the changes occurring in their bodies. Joint pain is the result of many factors like the ankles, feet, knees, and hips being under a lot of pressure, the excess fluid gain in the wrist and hands, and arthritis. In addition, the lack of enough calcium, and the release of the relaxin hormone, which loosens muscles and joints, can cause the pain.

Pregnant women in the third trimester should sleep on their left side, sleeping on any other side for a long period can make the body stiff and cause joint pains, notes parenting.

3 Mom Will Be So Tired

Many pregnant moms feel energetic during their second trimester and take advantage of this period to run important errands in preparation for the baby, like shopping for baby clothes. What they do not expect and what their doctors do not tell them is that fatigue will kick in in their third trimester.

Fatigue during the last trimester is the result of the growing bump. The growing baby normally puts physical strain on the body as pointed out by What to Expect and most of it during the last trimester. When moms get tired, they should take a nap or sit-down and relax for a few minutes.

2 There Will Be A Scale Increase

Doctors don't tell first-time moms that they will gain a few pounds during their third trimester. This is probably in their best interest because no pregnant woman wants to hear that she will get bigger than she already is. The increase on the scale is brought about by; the growing baby, the amniotic fluid, retention of fluids in the body, and the enlarging uterus, according to HealthLine.

Nutrition is key during pregnancy and moms should ensure that they eat healthy foods that will be of great benefit to the growing child. A good nutritionist can help moms manage this whole situation during this period.

1 Delivery Will Probably Take Longer Than Expected

In the third trimester, moms can start getting nervous about labor and delivery and this is probably why doctors do not tell first-time moms that their delivery might take longer as compared to second-time moms. As stated by What to Expect, labor for first-time moms can last for 12 to 18 hours and can even go on for longer.

Their first phase of labor usually lasts longer. The contractions during this period are mild so mom is able to distract herself through them. They intensify during the second phase of active labor. Moms-to-be can take Lamaze classes that can teach them how to prepare for labor.

Sources: babycenter.com, thebump.com, whattoexpect.com, netdoctor.co.uk, webmd.com, health.com, A. pregnancy.org,parenting.com, motherandbaby.co.uk, utswmed.org, motherlove.com, healthline.com, everydayhealth.com