During the first part of the second trimester, the developing fetus has not yet become large enough to crowd the abdomen and cause discomfort, and the risk of miscarriage has dropped significantly. For many women the time period is marked by a renewed sense of well being and happiness.
What Does the Second Trimester Mean for an Expectant Mother?
With each new week during the second trimester, a new stage of pregnancy is experienced by the mother and developing fetus. During the second trimester, an expectant mother can expect a rapid increase in the size of the uterus. At the end of the trimester, a developing fetus will be approximately four times larger than it was at the end of the first trimester.
Some expectant mothers experience discomfort and abdominal pain in the second trimester as a result of fetal and uterine growth, as organs are pushed aside to make room for the expanding uterus as the muscles of the pelvic area are being stretched. The hormones that affect a womans body during pregnancy such as estrogen, progesterone and relaxin are also responsible for physical changes.
For women who are expecting a first child, the pregnancy may not yet be obvious to other people. Clothing may be fitting a bit tighter, however maternity clothing is still too large. For women who have been pregnant before, the pregnancy may be showing by this time.
Other symptoms which can be attributed to the second trimester are food cravings, edema (swelling) in face, hands and feet, dizziness, bladder incontinence, constipation, skin tags and an increase in sex drive. Each pregnancy is different and while the symptoms and side effects of the second trimester are common, a woman may experience some, a few or absolutely none at all.
Fetal Development: Weeks 14-28
The second phase or trimester of pregnancy includes weeks fourteen through twenty-eight. During weeks thirteen through sixteen, the fetus undergoes rapid growth and begins to appear more human. However, around week seventeen, the growth begins to slow down, as the fetus starts to gain weight and fill out. The following information outlines the fetal development pattern during the second trimester of pregnancy:
- Week 14: the eyes move from the sides of the head to the front, bones are now detected on an x-ray. Nose, chin and forehead are now more defined, facial muscles attach and the fetus can smile, frown and wrinkle the brow. Unborn fetus has fingerprints, amniotic fluid regenerates itself every 3-4 hours and provides fetus with cushioning and protection. Fetus is around 3.2-4 inches in length and may weigh close to an ounce.
- Week 15: fetus is covered with lanugo (fine, downy hair covering an unborn infant), can hear maternal voice and heartbeat, colorless eyebrows and eyelashes also appear. Heart is pumping approximately 25 quarts of blood daily, scalp hair pattern develops, skin is thin and covered with vernix (greasy substance which protects skin from drying out). Fetal movements can be detected by the mother and is called quickening. Fetus is around 4-4 ½ inches long and weighs around 1-1 ½ ounces.
- Week 16: fetus becomes more active, increase movements and activity felt by mother, placenta is fully formed and functioning. Sometimes a fetus will experience hiccups, which are felt by the mother. Genitals are well-formed, gender can usually be determined via ultrasound exam. Developing fetus is drinking an average of 16 ounces of amniotic fluid per day. Fetus measures about 4.3-4 ½ inches in length and weighs approximately 3 ounces.
- Week 17: fetal activities increase even more, mother should note a drastic increase in movements. Fat deposits which helps for heat maintenance at birth are developing under the skin of fetus, loud external noises can startle fetus to move hands to cover the ears. Taste buds develop, further circulatory system development. Fetus weighs approximately 3 ½-4 ounces and is approximately 6-6 ½ inches in length.
- Week 18: fetus can now open the eyes, digestive system fully formed and active, bones are harder and stronger. Meconium appears in the bowel, if fetus is a boy, prostate gland is now functioning. Though no direct exchange of blood between the mother and fetus has occurred, the placenta is transferring nutrients and oxygen from maternal blood through the umbilical cord.
- Week 19: growing fetus has the same awake and sleep patterns as a newborn, has established a favorite sleeping position and recognizable active and restful periods. Through the fetal body, nerves are being coated with myelin, fatty insulation substance over which impulses travel. Scalp hair appears, milk teeth buds form and over the next few days the buds for permanent teeth appear behind the milk teeth. In female fetus, the uterus begins to form, if the fetus is a boy, the genitals are well formed. The baby is ingesting amniotic fluid and the kidneys are making urine. The fetus is approximately 6.3 inches long and weighs about 8.47 onces.
- Week 20: by this week pregnancy is officially half over. The stage of rapid growth is almost over and things have slowed down as the focus has shifted to survival. The fetal heart is growing stronger, the legs are reaching relative size and there is a marked increase in muscle growth and development. Maternal immunities are now being passed to the fetus, and will protect against viruses for up to six months after birth. Nerve cells for taste, smell, hearing seeing and touch are developed in the specialized areas of the brain. Fetus will startle in response to stimuli, if fetus is a girl approximately 6 million eggs are in the ovaries and will decrease to 1 million after birth. The fetus is about 6.46 inches in length and weighs around 10.60 ounces.
- Week 21: white blood cells (leukocytes) are forming, helping the fetus fight infection and disease. The skin has changed from translucent and appears more opaque, tongue has fully formed. In females, the uterus and vagina have formed. Fetus swallows more amniotic fluid and absorbs water in the liquid and moves the remaining fluid into the large bowel. Length is measured from crown-to-rump, baby weights about 12.7 ounces and measures 10.51 inches in length.
- Week 22: fetus can now hear conversations outside the womb, eyelids and eyebrows are fully formed, fingernails have grown to the tips of fingers. Fetal brain has entered a phase of rapid development, with maternal assistance the liver of the fetus is breaking down bilirubin. In males, the testicles begin to drop into the scrotum and produce testosterone. Fetus is around 1 pound in weight, length is approximately 10.94 inches.
- Week 23: body proportions are similar to a newborn, though thinner because fetus has not yet begun to develop body fat. The bones of the middle ear have begun to harden, eyes are completely formed, though the iris does not yet have pigmentation. The pancreas is developing steadily and making insulin, which is integral in the breakdown of glucose. If born now, the fetus has a 15% chance of survival, with odds increasing daily. Fetus is around 11.37 inches in length and weighs about 1.1 pound
- Week 24: fetus gains approximately 6 ounces in weight during this week, the increase comes from muscle, bone mass and vital organs. Body begins to fill out and taste buds start to form. Creases appear in the palms of hands, muscle coordination has improved allowing fetus to begin sucking thumb. Over the next week, the sweat glands form and lungs are developing “branches,” of the respiratory tree, cells in lungs begin to manufacture surfactant, which allows villi sacs of lungs to inflate with air. Fetus is considered viable, length is approximately 11.8 inches and weight is 1.4 pounds.
- Week 25: structures of the spine begin to form, blood vessels of the lungs develop. Fetal nostrils begin to open, nerves around the mouth and lips are more sensitive, swallowing reflex develop. Fetus is around 14 inches in length and weighs around 1.46 pounds.
- Week 26: the spine is becoming stronger and more supple, the spine contains 150 joints, 33 rings and more than 1,000 ligaments. Air sacs of the lungs now form, lungs begin secreting surfactant, eyes begin to open and blink, retinas form and brain wave activity on a fetal scan shows marked response to touch. Fetus is approximately 14 inches in length and weighs around 1.8- 2 pounds.
- Week 27: brain continues rapid growth, response to sounds grow more consistent, network of nerves to the ear will be completely developed by the end of the month. Lungs continue to grow and prepare for life after delivery. Eyelids are now open more and fetus can differentiate between light and dark, retinas have completely formed. Fetus grows more than an inch this week, average size of 14.4 inches and weight is around 1.9-2 pounds.
- Week 28: eyebrows and eyelashes are very noticeable, hair on head is growing longer, eyes are completely formed and body is becoming plumper and more rounded. Fat is added during the third trimester and muscle tone is improving, lungs are capable of breathing now. Fetus is now around 14.8 inches and weighs around 2.2 pounds.
What Does an Expectant Mother Experience During the 2nd Trimester?
During the second trimester of pregnancy, a female will experience the following physical changes:
- Larger breasts: stimulated by estrogen and progesterone, the mammary glands begin to enlarge. Additional fat accumulation can also occur, which can result in as much as 1 pound of extra breast tissue, or an addition of up to two bra cup sizes. Nipple tenderness may continue, a support bra is now advised.
- Growing belly: as the uterus becomes larger and heavier, the abdomen will expand rapidly.
- Braxton-Hicks contractions: uterus may begin contracting in preparation for impending delivery. Braxton-Hicks are painless and come and go with no set pattern. A woman should contact a doctor is cramps become consistent or painful, as it could be an indication of pre-term labor.
- Skin changes: as blood circulation increases, many women enjoy a healthy glow to the skin associated with pregnancy. Certain areas of skin may become darker, skin of nipples, parts of the face and lines that can run from the naval (belly button) to the pubic bone in particular.
- Nasal and gum problems: (possible, not always) pregnancy increases circulation, some blood goes through mucous membranes. This can cause the lining of nose and airway to swell, which can cause congestion and nosebleeds. The gums can become soft and minor bleeding can occur when brushing and flossing teeth.
- Dizziness: blood vessels dilate in response to pregnancy hormones. Until blood volumes increase to fill vessels, a woman may experience an occasional dizzy feeling. To alleviate condition avoid standing for long periods of time and rise slowly after lying or sitting down.
- Leg cramps: uterine pressure on the veins of the legs can cause leg cramping. Stretching muscles or taking walks can help reduce pain and likelihood of cramps.
- Heartburn and constipation: the movements that push swallowed food from the esophagus into the stomach are slower. The stomach takes longer to empty, the slowdown provides more time for the fetus to absorb the nutrients. The slowdown of digestion can cause heartburn and constipation. To help the condition it is recommended to add more fiber to the diet, increase fluid intake and eat, smaller more frequent meals.
- Shortness of Breath: the maternal lungs are processing up to 40% more air, allowing blood to carry more oxygen to the fetus. This can cause shortness of breath and faster breathing.
- Vaginal discharge: many pregnant women notice a thin, whitish colored normal vaginal discharge. The acidic change is thought to help suppression of harmful bacteria or yeast. If discharge is thick, foul smelling, green or yellowish in color and accompanied by redness or itching and irritation, a woman should contact a health care provider.
- Bladder and kidney infections: hormonal changes slow down urine production and the expanding uterus may get in the way. Both conditions may increase the risk of bladder and kidney infections. If painful or burning urination occur and are accompanied by a fever, abdominal pain or backache, a woman should contact a health care provider.
Maternal Check-up During 2nd Trimester
Prenatal appointments during the second semester focus on the growth of the fetus, confirmation of due date and detecting any issues that may be affecting maternal health. The health care provider will start by checking the maternal weight, urine and blood pressure. Next, the physician may measure fundal height, which is the distance from the top of the uterus to the pelvic bone. Pelvic examination is not necessary during the second trimester, unless the physician has detected something unusual that needs to be checked.
It is also normal for a woman to undergo a glucose tolerance test during the latter part of the second trimester. The test is done to detect the presence of gestational diabetes, which occurs only during pregnancy. A glucose tolerance test is done in two parts, first female drinks a sugary solution and an hour later, the blood is tested for sugar levels. If the test is positive, further tests may be ordered to confirm a diagnosis.
During the prenatal visit, the physician may check the fetal heartbeat using a Doppler (fetal stethoscope). An ultrasound may be ordered and the following blood tests called, “multiple markers,” will be done. The multiple markers are used to determine a womans risk of having an infant born with a certain genetic condition or birth defects. Fetal blood testing for multiple markers is most commonly done during weeks 15-20 of pregnancy and include the following:
Alpha-fetoprotein screening (AFP): a blood tested used to determine levels of alpha-fetoprotein in the mothers blood during pregnancy. AFP is produced normally by the fetal liver and is detected in the amniotic fluid of the uterus and crosses the placenta into the maternal blood supply. Another name for the AFP test is maternal serum AFP (MSAFP). Abnormal AFP levels can indicate neural tube defects, Down Syndrome, chromosomal abnormalities, defects in the fetal abdominal wall, more than one fetus or a miscalculation of due date.
Human Chorionic gonadotropin hormone (HGC): hormone made by the placenta.
Estriol: hormone produced by the placenta.
Inhibin: hormone made by the placenta.
Any type of abnormal results of an AFP or other marker test may indicate a need for further, more advanced testing. An ultrasound can be performed to confirm gestational age of fetus and to view fetal spine and other body parts for defects. A physician may also order an amniocentesis (test of amniotic fluid), which can be used to make an accurate diagnosis.
Multiple marker screening is not diagnostic, is not 100% accurate, it is only a screening test to determine if a mother needs additional testing during pregnancy. There can be false-positive results which can indicate a problem in a fetus that is actually healthy. A false-negative does the opposite, it causes a healthy result when a fetus actually does have some type of problem.
When testing is done during the first and second trimester, the ability of the tests to detect an abnormality is greater than by just using one screening alone. Nearly all cases of Downs Syndrome can be detected when using both first and second trimester screening.
Recommended Weight Gain for Women During the 2nd Trimester
While weight gain during pregnancy is important for fetal growth, gaining weight at a steady rate throughout pregnancy can also lower a womans chances of developing hemorrhoids, varicose veins, back pain, fatigue, stretch marks, indigestion and shortness of breath. The extra weight provides the fetus with nourishment and is stored for breastfeeding purposes after delivery.
The amount of weight gain recommended would depend on maternal weight prior to pregnancy. For a woman who was at a healthy pre-pregnancy weight, a gain of approximately 1-2 pounds per week during the second trimester is recommended. For women who were underweight before pregnancy, a weight gain of 1-2 pounds per week is recommended. If mother was overweight before pregnancy, a weight gain of 1 pound weekly during the last six months of pregnancy is recommended.
Throughout the pregnancy, a woman should aim to keep weight gain as steady as possible to ensure the growing fetus gets the daily supply of nutrients needed. It is normal for weight to fluctuate a bit at times, but a woman should contact a health care provider if a sudden weight gain or loss is experienced at any time during pregnancy.
If a woman is expecting twins or multiples, there are special guidelines for weight gain and nutritional requirements that would need to be discussed with a physician.
General Facts About the 2nd Trimester
There are some general facts about the second trimester of pregnancy that a woman may or may not experience. Much like the first trimester, the rapid changes cause an expectant mother to experience a wide array of physical, emotional and mental changes. Throughout the second trimester, there are general facts that most women become familiar with, which could include the following:
- Morning sickness: could still be experienced and might last through the entire pregnancy.
- Backaches: back curves more to accommodate the extra weight of the uterus which can result in backaches. May need to consult with physician and get a “belly belt,” which fits around lower abdomen of a pregnant woman and takes the pressure of the enlarged uterus off of the lower back.
- Hemorrhoids: veins around rectum can become enlarged and bleed, due to pressure of fetus and straining due to constipation. Consume more fiber and increasing fluids can help prevent constipation which is common during pregnancy.
- Skin problems: skin can become freckled or a dark pregnancy mask called chloasma can occur on the face. Wearing a wide brimmed hat and using sun screen in bright sunshine can help prevent the condition.
- Mouth and gum discomfort: brushing teeth can cause bleeding and sore gums due to hormonal changes. Visit the dentist and brush teeth and tongue twice daily and floss regularly, to ensure dental health during pregnancy.
- Dizziness and faintness: could indicate hypertension or low blood sugar. Should be checked by a physician.
- Indigestion and heartburn: taking antacids, avoiding greasy, deep fried foods, eating smaller meals, avoiding or limiting caffeine and not smoking can alleviate the condition.
- Headaches: may be due to hormonal and circulatory changes. Drinking enough fluids and minimizing stress can help headaches. A pregnant woman can take a pain reliever in the amount recommended by a physician to alleviate headaches.
- Difficulty breathing: avoid overexertion, slow down and take it easy, sleep in a propped up position.
- Leg cramps: due to circulatory changes, pressure on the nerves in the legs, or low calcium and potassium levels in the blood can result in leg cramps. Wearing support hose, taking short walks, elevating feet when resting, avoid tight fitting clothing, wear low healed shoes, rest and eating foods rich in calcium and potassium can help alleviate the condition. If it persists a woman needs to consult with her physician.
- Sleep issues: towards the middle to end of pregnancy, problems with insomnia are common. Taking frequent naps, drinking warm milk, taking a warm shower, and using supportive pillows may help an expectant mother be more comfortable and sleep better.
- Braxton-Hicks or pre-term labor contractions: addressed above.
The End of the 2nd Trimester
For many expectant mothers, the second trimester is a time when the impending reality of motherhood begins to truly sink in. The female body undergoes many continuous changes, first time fetal fluttering is felt and by the end of the trimester more pronounced kicking is normal as the fetus grows larger and takes up more uterine space.
By the end of the second trimester, the fetus weighs around 2 ½-3 pounds and is approximately 13-16 inches in length. Now that all of the major organs and systems have been completely formed, the remaining weeks will be spent growing. Fetal weight will multiply more than seven times and over the remaining weeks, the fetus will develop into a baby capable of sustaining life outside the womb.
While the second trimester is the most physically enjoyable for most expectant mothers, towards the end discomfort from an enlarged uterus and weight gain is common. At the end of the second trimester, the expectant mother and developing fetus are entering the final phase of pregnancy and preparing for the momentous task of labor and delivery, which marks the end of the long and arduous journey that occurs from conception to birth.